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Cited by 936biodegradable polymer synthesis and propertiesCarbon dioxide utilization in catalysisPolymer crystallization and properties

Catalysis as an Enabling Science for Sustainable Polymers

Open access
Zhang, Xiangyi, Fevre, Mareva, Jones, Gavin O., Waymouth, Robert M.·2018·Chemical Reviews
DOI 10.1021/acs.chemrev.7b00329
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Abstract

The replacement of current petroleum-based plastics with sustainable alternatives is a crucial but formidable challenge for the modern society. Catalysis presents an enabling tool to facilitate the development of sustainable polymers. This review provides a system-level analysis of sustainable polymers and outlines key criteria with respect to the feedstocks the polymers are derived from, the manner in which the polymers are generated, and the end-of-use options. Specifically, we define sustainable polymers as a class of materials that are derived from renewable feedstocks and exhibit closed-loop life cycles. Among potential candidates, aliphatic polyesters and polycarbonates are promising materials due to their renewable resources and excellent biodegradability. The development of renewable monomers, the versatile synthetic routes to convert these monomers to polyesters and polycarbonate, and the different end-of-use options for these polymers are critically reviewed, with a focus on recent advances in catalytic transformations that lower the technological barriers for developing more sustainable replacements for petroleum-based plastics.

AI snapshot

Written from the paper’s full text.

TL;DR

This review argues that catalysis is an enabling science for sustainable polymers, defined as renewable-feedstock-derived materials with closed-loop life cycles, and focuses on aliphatic polyesters and polycarbonates. It surveys catalytic routes from renewable feedstocks to monomers, polymerization methods, and end-of-use recycling or biodegradation, while noting incomplete sustainability metrics and economic/infrastructure barriers.

Key findings

  • Sustainable polymers are defined as materials derived from renewable feedstocks that exhibit closed-loop life cycles; aliphatic polyesters and polycarbonates are highlighted because they can be made from renewable monomers, synthesized by versatile routes, and are biodegradable or chemically recyclable.
  • Global plastics production grew from 1.65 million tons in 1950 to 311 million tons in 2014 and is expected to grow 3–4% per year; more than 300 million metric tons of plastic waste is generated annually, with 4.8–12.7 million metric tons entering the ocean.
  • Bio-derived plastics remain a small share: in 2014 only 1.7 megatons of more than 300 megatons of polymers produced globally were bio-derived, mainly PLA, biopolyethylene, and bioPET; in the United States in 2014, over 75% of plastic waste was landfilled, and plastics recycling rates are <10%.
  • Catalytic advances cited include MnCo2O4-supported Ru giving 99% FDCA yield from base-free air oxidation of HMF, zeolite-catalyzed one-step conversion of lactic acid to lactide at ~79% selectivity at full conversion, and TBD-catalyzed PLA alcoholysis reaching quantitative conversion in 2 min at room temperature with 1.5 equivalents of alcohol per ester bond.

Methods

  • This is a review and system-level analysis, not an experimental study; it considers feedstocks, monomer production, polymerization, use, and end-of-use options, focusing on polyesters and polycarbonates as representative sustainable materials.
  • It synthesizes literature on catalytic transformations from renewable feedstocks to monomers, monomers to polyesters and polycarbonates, and chemical or biological recycling/degradation, comparing routes by atom efficiency, green catalytic systems, and mild polymerization conditions.
  • It includes tabulated thermodynamic parameters for ring-opening polymerization of cyclic esters and comparison tables of polymerization methods for polyesters and polycarbonates.

Limitations

  • Stated: there is no universally recognized standard system or set of metrics for quantifying sustainability; life-cycle assessment results vary with modeling assumptions and feedstock choice, are often limited to cradle-to-gate, and switching from petroleum polymers to renewable-resource polymers does not necessarily reduce environmental impacts.
  • Stated: many biofeedstocks and biorefinery processes are costly or energy-intensive; sustainable polymers must meet cost and performance benchmarks; the existing plastics economic ecosystem is entrenched, and recovery/reuse infrastructure is underdeveloped.
  • Evident: as a review, it reports no new experimental data; its scope excludes biomedical biodegradation of aliphatic polyesters and polycarbonates and focuses on selected polymer classes, so quantitative comparisons depend on cited studies and their assumptions.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1021/acs.chemrev.7b00329

Cites

470 of 470 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

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  • Premisecitation

    The rate and time scale of CO2 sequestration for petroleum feedstocks (millions of years) is much slower than the use and release (1-10 year time frame).

    “This is in contrast to the carbon cycle for petroleum feedstocks, in which the rate and time scale of CO2 sequestration (millions of years) is much slower than the use and release (1-10 year time frame).”
    Quote in the paperNot a substantial claim
  • Premisereasoning

    LCA results are not available before production, much less during design, due to inadequate data.

    “That means, LCA results are not available before the production of a product, much less so during the design of a product as a result of inadequate data on environmental impacts.”
    Quote in the paperNot a substantial claim
  • Interpretationreasoning

    Bio-derived and biodegradable polymers are emerging as attractive alternatives to conventional petroleum-based polymers.

    “Such bio-derived and biodegradable polymers are therefore emerging * DGp° = standard free energy of polymerization as attractive alternatives to conventional petroleum-based polymers.”
    Quote in the paperNot a substantial claim
  • Interpretationreasoning

    For energetic efficiency, plastic materials should optimally be derived from polymerization reactions that are not strongly exergonic.

    “In order for this process to be energetically efficient, plastic materials should optimally be derived from polymerization reactions that are not strongly exergonic to ensure that, once generated, the materials can be catalytically depolymerized or chemically recycled with minimal energy inputs”
    Quote in the paperSubstantial claim
  • Premisereasoning

    Biodegradation requires engineering of polymer composition/formulation or degradation pathway to break down to CO2 and H2O in a reasonable time frame.

    “This requires engineering of either the polymer composition/formulation or its degradation pathway so that it can be broken down by microorganisms to primarily CO2 and H2O in a reasonable time frame.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 76
  • May combine two claims. 158
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Aliphatic polyesters and polycarbonates are promising materials due to their renewable resources and excellent biodegradability.

    “Among potential candidates, aliphatic polyesters and polycarbonates are promising materials due to their renewable resources and excellent biodegradability.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The amount of landfill space available for discarded plastic wastes is finite.

    “However, the amount of landfill space available for discarded plastic wastes is finite.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Even under optimized circular economies, some fraction of products will end up in the environment.

    “Even under the most highly optimized circular materials economies, some fraction of the products will eventually end up in the environment.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationcitation

    The point of maximum leverage is the socioeconomic system that has led to our current model of resource utilization.

    “While considerable research has focused on replacing petroleum raw materials with renewable sources and developing biodegradable or recyclable polymers that minimize waste disposal, 16 ultimately the point of maximum leverage 44 is the socioeconomic system that has led to our current model of resource utilization.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Life-cycle assessment results are variable across studies with quantification strongly tied to modeling assumptions and feedstock choice.

    “Life-cycle assessment has been used to assess the environmental impacts resulting from the production, use, and disposal of a polymer product (see section 1.5.2) but the results are variable across studies with quantification being strongly tied to modeling assumptions and feedstock choice.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Biodegradable plastics can mitigate some environmental consequences but are only one of several end-of-life strategies.

    “However, while biodegradable plastics can mitigate some of the environmental consequences of plastics that find their way into the environment, it is only one of the several end-of-life strategies to minimize the environmental impact of plastics.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Current rates of plastics recycling are exceedingly low (<10%) and are not keeping pace with increased production volumes.

    “Thus, while many petrochemically-based polymers are recyclable, the current rates of plastics recycling are exceedingly low (<10%) and, on a volume basis, are not keeping pace with the increased volumes of production.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    Plastics that end up in the environment should be biodegradable.

    “To mitigate the environmental impact of plastics that end up in the environment, these plastics should be biodegradable.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    New scientific and technological innovations are needed for efficient catalytic strategies to convert renewable resources into platform chemicals, monomers, polymers, and products economically.

    “As the chemical composition of renewable resources are quite different from those derived from petroleum-based resources, new scientific and technological innovations are needed for the development of efficient catalytic strategies for converting these resources into platform chemicals, monomers, polymers, and products that can be produced economically on a scale sufficient for commodity materials”
    Quote in the paperNot a substantial claim

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    Premisecitation

    Incineration of recovered plastic provides a potential source of energy but generates CO2 and requires purification to avoid hazardous releases.

    “Incineration of recovered plastic provides a potential source of energy, 39 but generates CO2; moreover, rigorous purification and process controls are needed to insure that the hazardous substances are not released into the atmosphere.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    LCA provides a standardized methodology to compare different product choices and identifies unintended environmental trade-offs.

    “LCA provides a standardized methodology to compare different product choices, and identifies unintended environmental trade-offs between impact categories.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Support from public and government including favorable policy and legislation is the key stimulator for technological innovations on sustainable polymers.

    “Support from public and government including favorable policy and legislation is the key stimulator for technological innovations on sustainable polymers and for businesses and customers to transition towards more sustainable products.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Several other reviews discuss sustainable polymers from the end-of-use perspective.

    “Several other reviews discuss the topic from the end-of-use perspective, covering different families of recyclable and biodegradable polymers.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    Catalysis presents an enabling tool to facilitate the development of sustainable polymers.

    “Catalysis presents an enabling tool to facilitate the development of sustainable polymers.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    Biodegradation is arguably not the optimal end-of-life option because energy invested is wasted.

    “It is arguably not the optimal end-of-life option in that the energy invested to create these materials is wasted and provides benefit only to the microbes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Many biomass-derived polymers have oxygen-rich backbones and are more readily degraded than all-carbon backbones of most petroleum-based polymers.

    “Although there is no direct correlation between a plastic's ability to biodegrade and the resource from which is derived, many biomass-derived polymers have oxygen-rich backbones and are thus more readily degraded than the all-carbon backbones of most petroleum-based polymers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    New strategies are needed for selective depolymerization of plastics to monomers or useful intermediates.

    “New strategies are needed for the selective depolymerization of plastics either to their constituent monomers or other useful intermediates that could be used as resources for other chemical processes”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    More sustainable alternatives must meet a high bar in cost and performance to be economically competitive.

    “One of the most significant challenges is that the plastics of modern society are quite remarkable materials; more sustainable alternatives will have to meet a high bar in terms of the cost and performance in order to be economically competitive.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Oilseed crops such as soybean, rapeseed, and oil palm are the major supply of oils at present.

    “Oilseed crops such as soybean, rapeseed, and oil palm are the major supply of oils at present, but algae has turned up as a cheaper alternative due to its non-food nature, fast production and recycle rate, and low use of production inputs.82”
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    Premisecitation

    Transition to non-food sources such as lignocellulosic biomass is an important direction to lower production costs and avoid resource competition with the food supply.

    “Transition to non-food sources such as lignocellulosic biomass is an important direction to lower the production costs [78][79][80] and to avoid resource competition with the food supply.”
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    Premisecitation

    Succinic acid is used in the production of bio-based PBS and is a versatile precursor for monomers such as 1,4-butanediol (BDO), g-butyrolactone (g-BL), maleic anhydride, and maleic acid.

    “Succinic acid is used in the production of bio-based PBS; it is also a versatile precursor for monomers such as 1,4-butanediol (BDO), g-butyrolactone (g-BL), maleic anhydride, and maleic acid.91”
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    • cites [91] source

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    Premisecitation

    Fatty acids obtained from transesterification of plant oils have been a long-standing biofeedstock for polymer production.

    “Fatty acids obtained from transesterification of plant oils have been a long-standing biofeedstock for polymer production.25,98”
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  • May combine two claims.

    Premisenone given

    The conversion of renewable monomers to polyesters and polycarbonates can be achieved via a variety of polymerization methods, enabling diverse backbone structures and side-chain functionalities that give rise to versatile physical properties.

    “Second, the conversion of these renewable monomers to polyesters and polycarbonates can be achieved via a variety of polymerization methods, which enables diverse backbone structures and side-chain functionalities that in turn give rise to versatile physical properties of these polymers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    In the last decade, a number of synthetic bio-derived plastics have been commercialized.

    “In the last decade, a number of synthetic bio-derived plastics have been commercialized.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Two important criteria for sustainable polymers are the use of renewable feedstock and the degradability or recyclability of the polymer.

    “While the sustainability of a polymer should be considered on a systems level that encapsulate a variety of factors in its feedstock, synthesis, and end-of-use options, two important criteria are the use of renewable feedstock and the degradability or recyclability of the polymer.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    Conversion of renewable feedstocks to monomers focuses on replacing existing petroleum-derived monomers with renewable counterparts and developing new bio-derived monomers and polymers with unique structures and properties.

    “The conversion of renewable feedstocks to monomers focuses on two directions: to replace the existing petroleum-derived monomers with their renewable counterparts, and to develop new bio-derived monomers and polymers with unique structures and properties that current commodity plastics do not have.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Although bio-based polymers save non-renewable resources and generally emit less greenhouse gases, studies have shown they may exert higher environmental impacts in eutrophication and stratospheric ozone depletion.

    “Although bio-based polymers save non-renewable resources and generally emit less greenhouse gases for their production, studies have shown that they may exert higher environmental impacts in the categories of eutrophication and stratospheric ozone depletion.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In 2014, only 1.7 megatons of more than 300 megatons of polymers produced globally were bio-derived, with the three main products being PLA, biopolyethylene, and bioPET.

    “For example, in 2014 only 1.7 megatons of more than 300 megatons of polymers produced globally were bio-derived, of which the three main products were PLA, biopolyethylene, and bioPET.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    These are attractive candidates for feedstock recycling as polymerization thermodynamics are not as exergonic as those of conventional commodity plastics.

    “Alternatively, these are attractive candidates for feedstock recycling as the polymerization thermodynamics are not as exergonic as those of conventional commodity plastics (PE, PS, PVC).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Diacids and hydroxyl acids are key monomers for various commodity polyesters and polycarbonates, and serve as a platform for high-value added products by chemical and biological transformations.

    “They are not only key monomers for various commodity polyesters and polycarbonates, but also serve as a platform for a multitude of highvalue added products by means of chemical and biological transformations.77”
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  • May combine two claims.

    Premisenone given

    Among polymers that can be both renewable and degradable, polyesters and polycarbonates have attracted the most attention and many have been used as substitutes for petroleum-based plastics.

    “Among the families of polymers that can be both renewable and degradable (upper right quadrant), polyesters and polycarbonates have attracted the most attention, with a great many of them been successfully used as substitutes for plastics of petroleum origin.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Poly(ethylene furandicarboxylate) (PEF) produced from FDCA is regarded as a renewable substitute for PET.

    “Poly(ethylene furandicarboxylate) (PEF) produced from FDCA is regarded as a renewable substitute for PET.104”
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    • cites [104] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    PLA produced from starch-rich crops is an important example, developed by Natureworks LLC under the brand name Ingeo.

    “One important example is PLA produced from starch-rich crops such as corn; for example, that developed by Natureworks LLC under the brand name Ingeo TM .60”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Adipic acid is one of the most important diacids in industry and about 2.5 million tons are produced annually from petrochemicals.

    “Adipic acid, a monomer used for the production of nylon, polyurethane, and polyesters, is one of the most important diacids in industry and ~2.5 million tons are produced annually from petrochemicals.96”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [96] Bohnet M., 2003

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The role of catalysis in these conversions is critical and many research efforts are focusing on developing green catalytic processes with high efficiency and low cost.

    “The role of catalysis in these conversions is critical and many research efforts are focusing on developing green catalytic processes with high efficiency and low cost.[84][85][86]”
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  • May combine two claims.

    Interpretationreasoning

    Polyesters and polycarbonates have met several key principles for a sustainable polymer, enabling a potentially cyclic model of resource utilization.

    “They have met several key principles outlined for a sustainable polymer (section 1.3), which enables a potentially cyclic model of resource utilization.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Traditional polymers are derived from fossil fuels and are non-degradable, whereas sustainable polymers are sourced from renewables and can readily degrade.

    “Traditional polymers are derived from fossil fuels and are non-degradable in nature (lower left quadrant), whereas sustainable polymers are sourced from renewables and can readily degrade in the environment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In Landis's analysis, biopolymers such as PLA and PHA were ranked highest based on green design metrics but in the middle of LCA rankings, whereas petroleum polymers such as PE and PP were ranked highest in LCA but in the middle of green design rankings.

    “In this analysis, biopolymers such as polylactide (PLA) and polyhydroxyalkanoate (PHA) were ranked the highest based on green design metrics but in the middle of the LCA rankings whereas petroleum polymers such as PE and PP were ranked the highest in the LCA rankings but in the middle of green design rankings.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Plant oil is converted to fatty acids and glycerol for biodiesel and oleochemical production.

    “Another common renewable resource is plant oil, which is converted to fatty acids and glycerol for biodiesel and oleochemical production.16,25,81”
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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    This allows a faster rate of resource regeneration than resource consumption.

    “This allows a faster rate of resource regeneration than resource consumption.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The two metrics focus on different aspects of sustainability, so evaluations can give different results.

    “Since the two metrics focus on different aspects of sustainability, the evaluation based on these metrics can give different results.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Synthetic plastics on the market can be classified into four categories according to feedstock renewability and polymer degradability.

    “As summarized in Figure 2, synthetic plastics on the market can be classified into four categories according to their feedstock renewability and polymer degradability.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Sugar fermentations to produce polyols such as sorbitol, mannitol, xylitol are feasible although they cannot yet compete with chemical reduction economically.

    “Sugar fermentations to produce these polyols are also feasible although it cannot yet compete with the chemical reduction economically.[149][150][151]”
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    Premisecitation

    The coupling of diols with CO2 occurred at 25 °C and ambient pressure, affording cyclic carbonates in 40-70% yields.

    “The coupling of diols with CO2 occurred at 25 °C and ambient pressure, affording cyclic carbonates in 40-70% yields.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [202] source

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  • May combine two claims.

    Interpretationcitation

    The use of halide is crucial for the conversion, highlighting the importance of the leaving group.

    “The use of halide is crucial for the conversion, highlighting the importance of the leaving group.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Lactic acid is a well-recognized bio-based chemical, currently produced from starch crops via bacteria fermentation.

    “Lactic acid is a well-recognized bio-based chemical, currently produced from starch crops via bacteria fermentation.91”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [91] source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Buchard reported an efficient two-step procedure using DBU as the base in the first step to activate the hydroxyl group toward carbonylation and NH3/TsCl in the second step to facilitate the cyclization.

    “Recently, Buchard reported an efficient two-step procedure using DBU as the base in the first step to activate the hydroxyl group toward carbonylation and NH3/TsCl in the second step to facilitate the cyclization.202”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [202] source

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  • May combine two claims.

    Interpretationcitation

    The yields of biological or chemical production of glycolic acid are typically low, which makes them hard to compete with the current petroleum-based synthesis.

    “However, the yields of these processes are typically low, which makes them hard to compete with the current petroleum-based synthesis.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [158] Dischert, W.; Colomb, C.; Soucaille, P.Fermentation Process for Producing Glycolic Acid. U.S. 20120178136A1, 2012.

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    • cites [159] source

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  • May combine two claims.

    Premisecitation

    The second step of lactide production requires the use of a selective catalyst, typically tin octoate, and continuous removal of lactide to achieve good yield.

    “This second step requires the use of a selective catalyst, typically tin octoate, 156 and continuous removal of lactide (e.g. by distillation) to achieve good yield.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [156] source

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  • May combine two claims.

    Premisenone given

    Dehydrative condensation of CO2 and alcohols is the most straightforward and green route to dialkyl carbonates but the reaction is severely limited by the unfavorable equilibrium.

    “Dehydrative condensation of CO2 and alcohols is the most straightforward and green route to dialkyl carbonates but the reaction is severely limited by the unfavorable equilibrium.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The most successful cyclic ester derived from biomass is lactide (LA), the monomer for commodity polylactides (PLAs).

    “The most successful cyclic ester derived from biomass is lactide (LA), the monomer for commodity polylactides (PLAs).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    These monomers can undergo polymerizations at both the alkene and ester site, making them potential substitutes for petroleum-based polyacrylates and polyesters.

    “These monomers can undergo polymerizations at both the alkene and ester site, making them potential substitutes for petroleum-based polyacrylates and polyesters.176,177”
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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Ethylene glycol (EG), a component for PET, is traditionally produced from petroleum-based ethylene, via the intermediate ethylene oxide.

    “Ethylene glycol (EG), a component for PET, is traditionally produced from petroleum-based ethylene, via the intermediate ethylene oxide.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Hydrogenolysis of sugar-derived polyols (glycerol, xylitol, sorbitol) catalyzed by supported transition-metal catalysts, mostly Ru, Cu, Ni, under basic conditions, provides a direct and potentially cheaper route to EG but is complicated by concurrent generation of other polyols like propylene glycol.

    “Another promising route is the hydrogenolysis of sugarderived polyols (glycerol, xylitol, sorbitol) catalyzed by supported transition-metal catalysts, mostly Ru, Cu, Ni, under basic conditions.126,127 This process provides a direct and potentially cheaper route to EG but is complicated by the concurrent generation of other polyols, like propylene glycol (PG).”
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    • cites [126] source

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  • May combine two claims.

    Premisecitation

    The shape-selective property of zeolites enables high selectivity for LA (~79% at full conversion), devoid of racemization and side-product formation.

    “The shape-selective property of zeolites enables high selectivity for LA (~79% at full conversion), devoid of racemization and side-product formation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [157] source

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  • May combine two claims.

    Interpretationreasoning

    Both steps of lactide production are time- and energy-intensive owing to their reliance on high temperatures and vacuum.

    “Both steps are time-and energy-intensive owing to their reliance on high temperatures and vacuum.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    The syntheses of cyclic esters directly from sugar precursors typically involve elaborate protecting group chemistry, which compromises the atom economy and production cost of these monomers.

    “Their syntheses typically involve elaborate protecting group chemistry, which compromises the atom economy and production cost of these monomers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Since furfural is industrially produced from lignocellulose on a scale of 400 kilotons a year, producing FDCA from furfural provides a potentially cheaper route to FDCA.

    “Since furfural is industrially produced from lignocellulose on a scale of 400 kilotons a year, this provides a potentially cheaper route to FDCA.115”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [115] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The thermodynamics of the dehydrative cyclization reaction to cyclic carbonates from CO2 is unfavorable, similar to the synthesis of dialkyl carbonate from CO2.

    “The thermodynamics of this dehydrative cyclization reaction is unfavorable, similar to the synthesis of dialkyl carbonate from CO2. 184”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [184] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    The development of petroleum-based plastics has been driven by the innovations in catalytic petrochemistry and polymerization methods.

    “The development of petroleum-based plastics has been driven by the innovations in catalytic petrochemistry and polymerization methods.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Due to the wide availability of diols, diacids or hydroxy acids, SGP provides easy access to polyesters and polycarbonates with diverse backbone structures and side-chain functionalities.

    “Due to the wide availability of diols, diacids or hydroxy acids, SGP provides easy access to polyesters and polycarbonates with diverse backbone structures and side-chain functionalities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Most bio-derived epoxides are prepared by catalytic epoxidation of alkene group present in a renewable substrate.

    “Most bio-derived epoxides are prepared by catalytic epoxidation of alkene group present in a renewable substrate.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Epichlorohydrin (ECH), an important industrial chemical produced on a 1.8 million tons scale annually, can be derived from glycerin through a two-step reaction.

    “Epichlorohydrin (ECH), an important industrial chemical produced on a 1.8 million tons scale annually, can be derived from glycerin through a two-step reaction.208,209”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [208] source

      Not checked in the free run.

    • cites [209] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The removal of by-products, water or alcohol, from polycondensation reactions necessitates the use of high temperatures and often vacuum conditions, which makes this approach very energy-intensive.

    “In addition, the removal of by-products, water or alcohol, from the polycondensation reactions necessitates the use of high temperatures and often times vacuum conditions, which makes this approach very energy-intensive.218”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [218] Odian G., 2004 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The traditional way of synthesizing polyesters and polycarbonates is by step-growth polymerization.

    “The traditional way of synthesizing polyesters and polycarbonates is by step-growth polymerization.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Although these approaches use cheap, safe, and renewable feedstocks and operate under relatively mild conditions, the generation of stoichiometric wastes and the moderate yields of these reactions limit their atomic efficiencies.

    “Although these approaches use cheap, safe, and renewable feedstocks and operate under relatively mild conditions, the generation of stoichiometric wastes and the moderate yields of these reactions limit their atomic efficiencies.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The effective uses and transformations of renewable feedstocks to sustainable polymers rely on the development of innovative and green catalytic chemistries.

    “Similarly, the effective uses and transformations of renewable feedstocks to sustainable polymers rely on the development of innovative and green catalytic chemistries.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    Because the water by-product is expelled out of the hydrophobic interior of micelles, the DBSA-mediated emulsion polycondensation can proceed effectively at low temperature (40-80 °C) and 1 atm.

    “Since the water by-product is expelled out of the hydrophobic interior of micelles, this reaction can proceed effectively at low temperature (40-80 °C) and 1 atm.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The use of a chemoselective catalyst is critical to eliminate the need for tedious and uneconomical protection chemistry and to enhance product specificity.

    “The use of a chemoselective catalyst is critical to eliminate the need for tedious and uneconomical protection chemistry 239,240 and to enhance the product specificity.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [239] source

      Not checked in the free run.

    • cites [240] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Bismuth triflate has received particular attention due to its low toxicity, low cost, and stability.

    “Among different metals, bismuth triflate (Bi(OTf)3) has received particular attention due to its low toxicity (Bi 3+ is among the least toxic heavy metal ions), low cost, and stability.234”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [234] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Organic carbonates can be produced on a large scale from CO, or potentially from CO2.

    “They can be produced on a large scale from CO, or potentially from CO2. 183,184”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [183] source

      Not checked in the free run.

    • cites [184] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The development of catalytic processes that can operate at lower temperatures will reduce the energy input and thus increase the sustainability of step-growth synthesis.

    “The development of catalytic processes that can operate at lower temperatures will reduce the energy input, and thus increase the sustainability of the step-growth synthesis.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Pendant hydroxyl groups not only enable post-polymerization functionalization but also provide a handle to tailor the crystallinity of these aliphatic polyesters.

    “The pendant hydroxyl groups not only enable post-polymerization functionalization but also provide a handle to tailor the crystallinity of these aliphatic polyesters.242”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [242] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    To date, the activity of organocatalysts for step-growth polymerization and the molecular weights of the resulting polyesters and polycarbonates are not yet comparable to the most efficient metal catalysts.

    “To date, the activity of organocatalysts for SGP and the molecular weights of the resulting polyesters and polycarbonates are not yet comparable to the most efficient metal catalysts.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    The direct coupling of CO2 and diols is severely limited by the reaction equilibrium and requires an effective dehydration system.

    “The direct coupling of CO2 and diols is severely limited by the reaction equilibrium and requires an effective dehydration system.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Further modification of the resulting unsaturated polyesters by Michael addition yielded polyesters with different substituents dangling off the backbone, which provided a means to tune the thermal property of the materials.

    “Further modification of the resulting unsaturated polyesters by Michael addition yielded polyesters with different substituents dangling of the backbone, which provided a means to tune the thermal property of the materials.233”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [233] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    For the step-growth synthesis of polycarbonates, the replacement of hazardous phosgene with more renewable and eco-friendly carbonyl reagents is a subject of intensive research.

    “For the step-growth synthesis of polycarbonates, the replacement of hazardous phosgene with more renewable and eco-friendly carbonyl reagents is a subject of intensive research.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    High yields (>90%) and high molecular weights (Mn in the range of 10-40 kDa) were achieved for a variety of diols and dihalides substrates with Feng and Gnanou's system.

    “High yields (> 90%) and high molecular weights (Mn in the range of 10-40 kDa) were achieved for a variety of diols and dihalides substrates.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [265] source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    While the ROP of five-membered cyclic carbonates is enthalpically disfavored, six- and seven-membered cyclic carbonates can undergo facile and controlled ROP under mild conditions.

    “While the ROP of fivemembered cyclic carbonates is enthalpically disfavored, six-and seven-membered cyclic carbonates (6CCs, 7CCs) can undergo facile and controlled ROP under mild conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Four-, six-, and seven-membered rings are favorable for ROP due to their large ring strains, while five-membered lactones such as γ-butyrolactone exhibit a less favorable enthalpy of polymerization and are usually considered nonpolymerizable.

    “Four-, six-, and seven-membered rings are favorable for ROP due to their large ring strains while five-membered lactones such as γ-butyrolactone (γ-BL) exhibits a less favorable enthalpy of polymerization and is usually considered as nonpolymerizable.277”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [277] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The synthetic versatility of six-membered cyclic carbonates allows the incorporation of a wide range of functional groups to the resulting polycarbonates, which has led to a versatile material platform for biomedical applications.

    “The synthetic versatility of 6CCs allows the incorporation of a wide range of functional groups to the resulting polycarbonates, which has led to a versatile material platform for biomedical applications.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [282] source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    With the proper choice of an initiating/catalytic system, ROP of cyclic esters and carbonates can be performed under mild conditions (room temperature, ambient pressure) to give high yield and 100% atom economy, making ROP a highly efficient and green route for the synthesis of polyesters and polycarbonates.

    “With the proper choice of an initiating/catalytic system, ROP of cyclic esters and carbonates can be performed under mild conditions (room temperature, ambient pressure) to give high yield and 100% atom economy, which makes ROP a highly efficient and green route for the synthesis of polyesters and polycarbonates.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Quantitative conversions of diols were achieved under 5 MPa CO2 with Tomishige's system, but the molecular weights of the obtained polycarbonates were extremely low (Mn < 1700 Da).

    “Quantitative conversions of diols were achieved under 5 MPa CO2 but the molecular weights of the obtained polycarbonates were extremely low (Mn < 1700 Da).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [263] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Similar limitations on ring size exist for cyclic carbonates.

    “Similar limitations on ring size exist for cyclic carbonates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Du employed CH2Cl2 as the dihalide and condensed it with various diols and 1 atm of CO2 to give polymers with Mn up to 11 kDa.

    “In another study, Du employed CH2Cl2 as the dihalide and condensed it with various diols and 1 atm of CO2 to give polymers with Mn up to 11 kDa (Scheme 5e).266”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [266] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    N-substitution not only enhances the ring strain but also provides a synthetic handle to introduce functionality to these polycarbonates.

    “The N-substitution not only enhances the ring strain but also provides a synthetic handle to introduce functionality to these polycarbonates.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [283] source

      Not checked in the free run.

    • cites [284] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Only moderate yields (<60%) and low molecular weights (Mn up to 6 kDa) were achieved with Kadokawa's PR3/CBr4/base system.

    “Only moderate yields (< 60%) and low molecular weights (Mn up to 6 kDa) were achieved.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [261] source

      Not checked in the free run.

    • cites [262] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    Catalytic processes performed at mild temperature, low catalyst loading, and solvent-free conditions are particularly attractive from a sustainability standpoint.

    “In addition, catalytic processes performed at mild temperature, low catalyst loading, and solvent-free conditions are particularly attractive from a sustainability standpoint.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Intramolecular chain transfer such as cyclization and backbiting of chain end onto an internal ester group leads to the formation of cyclic polyesters; intermolecular chain transfer (transesterification) results in chain scrambling and broadens the molecular weight distribution.

    “As depicted in Scheme 6, intramolecular chain transfer such as cyclization (kcy) and backbiting (kbb) of chain end onto an internal ester group leads to the formation of cyclic polyesters; intermolecular chain transfer (transesterification) results in chain scrambling (ksc) and broadens the molecular weight distribution.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [273] Duda A., 2009

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Some metal catalysts show extremely high reactivity (TOF > 1000 h-1) and high regio-/stereoselectivity for the ROP of asymmetric monomers.

    “Some of these catalysts show not only extremely high reactivity (TOF > 1000 h -1 ) but also high regio-/stereoselectivity for the ROP of asymmetric monomers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The aggregation of alkali metal salts, lithium in particular, often complicates the polymerization kinetics.

    “The aggregation of alkali metal salts, lithium in particular, often complicates the polymerization kinetics.287”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [287] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    Simple metal alkoxides and carboxylates such as tin octoate are cheap and convenient catalysts for ROPs and are used industrially to produce PLA.

    “Simple metal alkoxides and carboxylates such as tin octoate are cheap and convenient catalysts for ROPs and are used industrially to produce PLA.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The most commonly used catalysts for ROP are transition and posttransition metal complexes, which mediate ROP through a coordination-insertion type mechanism.

    “The most commonly used catalysts for ROP are transition and posttransition metal complexes, which mediate the ROP through a “coordination-insertion” type mechanism (Scheme 7).289”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [289] source

      Not checked in the free run.

  • The quote only partly states this claim.

    Premisereasoning

    When it comes to selectivity, especially stereoselectivity, well-defined single-site metal catalysts with ancillary ligands are more competent than simple metal alkoxides and carboxylates.

    “However, when it comes to selectivity, especially stereoselectivity, those well-defined single-site metal catalysts with ancillary ligands are more competent.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    The ancillary ligand has proven to be an important element in ROP catalysis to fine tune the electronic and steric properties of the metal center and to control the selectivity of polymerization.

    “The ancillary ligand has proven to be an important element in ROP catalysis to fine tune the electronic and steric properties of the metal center and to control the selectivity of polymerization.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Aluminum complexes supported by SALEN-type ligands are some of the most stereoselective catalysts for the ROP of racemic LA, but their low reactivities limit their applicability.

    “Aluminum complexes supported by SALEN-type ligands [301][302][303][304][305][306][307][308][309] are some of the most stereoselective catalysts for the ROP of racemic LA but their low reactivities (typical reaction conditions: Al loading >1 mol%, 70-130 °C, and long reaction time) limit their applicability.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [301] source

      Not checked in the free run.

    • cites [302] source

      Not checked in the free run.

    • cites [303] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Unlike the previous case, the two monomers exhibited orthogonal reactivity with one being completely inactive during the polymerization of the other.

    “Unlike the previous case, the two monomers exhibited orthogonal reactivity with one being completely inactive during the polymerization of the other.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [320] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    PHAs are naturally produced by various bacteria but only isotactic microstructures are made biologically.

    “PHAs are naturally produced by various bacteria (section 3.3) but only isotactic microstructures are made biologically.317”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [317] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisereasoning

    Among all chiral monomers, the stereoselective ROP of lactide has been most extensively studied because of the important application of PLAs.

    “Among all chiral monomers, the stereoselective ROP of lactide has been most extensively studied because of the important application of PLAs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    This provides new possibilities for engineering the properties and applications for these plastics.

    “This provides new possibilities for engineering the properties and applications for these plastics.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Rare-earth metal catalysts supported by phosphasalen ligands displayed both high reactivity and stereoselectivity (Pi up to 0.84 at 25 °C) with the ability to produce high molecular weight isotactic PLAs (Mn > 100 kDa) with extremely narrow polydispersities (Ð < 1.1).

    “Rare-earth metal catalysts supported by phosphasalen ligands (such as Ln-phosSALEN in Figure 8) displayed both high reactivity and stereoselectivity (Pi up to 0.84 at 25°C) with the ability to produce high molecular weight isotactic PLAs (Mn > 100 kDa) with extremely narrow polydispersities (Ð <1.1).310,311”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [310] source

      Not checked in the free run.

    • cites [311] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    They found that the reduced form was much more active towards LA than CL while the oxidized form had the opposite selectivity.

    “They found that the reduced form was much more active towards LA than CL while the oxidized form had the opposite selectivity.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [319] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Given that many cyclic esters and carbonates monomers derived from plants contain stereocenters, stereoselective ROP is an important aspect for the controlled synthesis of sustainable polymers.

    “Given that many cyclic esters and carbonates monomers derived from plants contain stereocenters, the stereoselective ROP is an important aspect for the controlled synthesis of sustainable polymers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    No appreciable amount of ether linkage was detected in the resulting polymers, indicating the absence of decarboxylation reaction.

    “No appreciable amount of ether linkage was detected in the resulting polymers, indicating the absence of decarboxylation reaction.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [297] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    End-group analysis revealed an imidazolium enol-like chain end of the final polymers, indicative of an intramolecular proton transfer within the zwitterionic intermediates generated from the nucleophilic addition of NHOs to the monomer.

    “End-group analysis revealed an imidazolium enol-like chain end of the final polymers, indicative of an intramolecular proton transfer within the zwitterionic intermediates generated from the nucleophilic addition of NHOs to the monomer (Scheme 11D).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [335] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Organic acids such as sulfonic or phosphoric acid can catalyze the polymerization through electrophilic activation of monomers.

    “Organic acids such as sulfonic or phosphoric acid can catalyze the polymerization through electrophilic activation of monomers.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    Typical nucleophilic organocatalytic ROP is subject to a trade-off between rate and selectivity: the most active catalysts, i.e. NHCs and TBD, tend to promote side reactions such as chain transfer and epimerization especially at high conversions while the most selective systems, such as TU/amines, suffer from slow kinetics.

    “Typical nucleophilic organocatalytic ROP is subject to a trade-off between rate and selectivity: the most active catalysts, i.e.NHCs, TBD, tend to promote side reactions such as chain transfer and epimerization especially at high conversions while the most selective systems, such as TU/amines, suffer from slow kinetics.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    While non-substituted NHOs were ineffective for ROP due to catalyst deactivation, NHO bearing dimethyl substituents proved highly active for the ROP of LA and VL.

    “While non-substituted NHOs (at the exocyclic carbon, NHO-1,3) were ineffective for ROP due to catalyst deactivation (Scheme 11C), NHO bearing dimethyl substituents (NHO-2) proved highly active for the ROP of LA and VL.334”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [334] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Under the same conditions, the ROP of VL is fast but poorly controlled due to the more significant enolate-based initiation.

    “Under the same conditions, the ROP of VL is fast but poorly controlled due to the more significant enolate-based initiation.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [334] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The high activity and the ability to operate through different polymerization mechanisms make NHO an attractive motif for future catalyst design and optimization.

    “The high activity and the ability to operate through different polymerization mechanisms make NHO an attractive motif for future catalyst design and optimization.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    They found that the dizinc acetate catalyst was an excellent catalyst for the ring-opening copolymerization of epoxide and CO2 but not for the ROP of CL.

    “They found that the dizinc acetate catalyst (Zn-OAc) was an excellent catalyst for the ring-opening copolymerization of epoxide and CO2 but not for the ROP of CL.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [322] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the presence of an alcohol initiator, the ROP of 50 equiv L-LA by as low as 0.2 mol% NHO-2 reached quantitative conversion in less than a minute, resulting in PLAs with low molecular weight distributions (Ð < 1.2).

    “In the presence of an alcohol initiator, the ROP of 50 equiv.L-LA by as low as 0.2 mol% NHO-2 reached quantitative conversion in less than a minute, resulting in PLAs with low molecular weight distributions (Ð <1.2).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [334] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Since the pioneering work of Hedrick in 2001, the application of organic catalysts to ROP has witnessed significant progress in the last 15 years and this field has grown to the point that it now provides a powerful and, in some cases, better alternative to the use of traditional metal-based catalysts.

    “Since the pioneering work of Hedrick in 2001, 324 the application of organic catalysts to ROP has witnessed significant progress in the last 15 years and this field has grown to the point that it now provides a powerful and, in some cases, better alternative to the use of traditional metal-based catalysts.325,326”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [324] source

      Not checked in the free run.

    • cites [325] source

      Not checked in the free run.

    • cites [326] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    These ionic catalysts are prepared by simple deprotonation of the neutral ureas or thioureas.

    “These ionic catalysts are prepared by simple deprotonation of the neutral ureas or thioureas.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [321] source

      Not checked in the free run.

    • cites [336] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    The diversity in mechanistic pathways not only provides new opportunities for enhancing the rate and selectivity of polymerization but also enables the synthesis of polymer architectures that are difficult to access by metal-mediated processes.

    “The diversity in mechanistic pathways not only provides new opportunities for enhancing the rate and selectivity of polymerization but also enable the synthesis of polymer architectures that are difficult to access by metal-mediated processes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    These systems have proven especially selective for chain propagation over transesterification, affording narrowly dispersed polyesters and polycarbonates.

    “These systems have proven especially selective for chain propagation over transesterification, affording narrowly dispersed polyesters and polycarbonates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    While low stereo-control at ambient temperature has been a long-standing problem for organocatalytic ROP, recent advances in catalyst design have demonstrated the potential of organocatalysts to rival the state-of-the-art metal catalysts.

    “While low stereo-control at ambient temperature has been a long-standing problem for organocatalytic ROP, recent advances in catalyst design have demonstrated the potential of organocatalysts to rival the state-of-the-art metal catalysts.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Chen developed a bifunctional catalyst that combines β-isocupreidine, a previously reported chiral ROP catalyst with low enantioselectivity (kL/kD = 4.4), and a chiral thiourea based on the binaphthyl scaffold.

    “Chen developed a bifunctional catalyst that combines b-isocupreidine, a previously reported chiral ROP catalyst with low enantioselectivity (kL/kD = 4.4), 340 and a chiral thiourea based on the binaphthyl scaffold.341”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [340] source

      Not checked in the free run.

    • cites [341] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Urea anions are more active than the corresponding thiourea anions, with the ability to polymerize all tested monomers in just seconds (<12 s) with excellent control on molecular weight distributions (Ð = 1.06-1.14).

    “The urea anions are more active than the corresponding thiourea anions, with the ability to polymerize all tested monomers in just seconds (<12s) with excellent control on molecular weight distributions (Ð =1.06 ~ 1.14).336”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [336] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The most active one, a trisurea/MTBD, is approximately 100 times faster than mono-TU/MTBD for the ROP of CL, with equally good control on molecular weights and molecular weight distributions (Ð < 1.05).

    “The most active one, a trisurea/MTBD, is approximately 100 times faster than mono-TU/MTBD for the ROP of CL, with equally good control on molecular weights and molecular weight distributions (Ð < 1.05).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [337] source

      Not checked in the free run.

    • cites [338] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    exo-PRO exhibited a strong preference for L-LA and the ROP of rac-LA by this catalyst at 50% conversion generates highly isotactic PLAs with Pm up to 0.96 at 25 °C.

    “exo-PRO exhibited a strong preference for L-LA and the ROP of rac-LA by this catalyst at 50% conversion generates a highly isotactic PLAs with Pm up to 0.96 at 25 °C.342”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [342] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Kiesewetter reported a series of bis- and tris-(thio)urea based H-bond donors, which exhibited dramatic rate acceleration compared to the mono-TU/amine systems, yet retaining the high selectivity for propagation over transesterification.

    “Kiesewetter reported a series of bis-and tris-(thio)urea based H-bond donors (Scheme 13), which exhibited dramatic rate acceleration compared to the mono-TU/amine systems, yet retaining the high selectivity for propagation over transesterification. 337,338”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [337] source

      Not checked in the free run.

    • cites [338] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The rate acceleration is proposed to arise from an "activated (thio)urea" mechanism in which each additional (thio)urea moiety enhances the acidity via intramolecular H-bond activation, supported by DFT calculations.

    “The rate acceleration is proposed to arise from an “activated (thio)urea” mechanism in which each additional (thio)urea moiety enhances the acidity via intramolecular H-bond activation (Scheme 13), supported by DFT calculations.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [337] source

      Not checked in the free run.

    • cites [338] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    While these heterogeneous catalysts can show good reactivities, they lack sufficient control on the polymerizations and the structures of the active species are ill-defined.

    “While these catalysts can show good reactivities, they lack sufficient control on the polymerizations and the structures of the active species are ill-defined.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [353] source

      Not checked in the free run.

    • cites [354] source

      Not checked in the free run.

    • cites [355] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    One obvious advantage of epoxide/CO2 copolymerization is the utilization of CO2 as a monomer.

    “One obvious advantage of epoxide/CO2 copolymerization is the utilization of CO2 as a monomer.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    While the field of epoxide/CO2 copolymerization is quite mature, with several technologies commercialized, the progress in epoxide/cyclic anhydride copolymerization is more recent.

    “While the field of epoxide/CO2 copolymerization is quite mature, with several technologies been commercialized, the progress in epoxide/cyclic anhydride copolymerization is more recent.211,343”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [211] source

      Not checked in the free run.

    • cites [343] source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Depending on the epoxide, epoxide/CO2 copolymerization enables 30-50% of a polymer's mass to be derived from CO2, with the rest derived from cheap platform petrochemicals, or potentially from renewable biomass.

    “Depending on the epoxide, this method enables 30-50% of a polymer's mass to be derived from CO2, with the rest derived from cheap platform petrochemicals, or potentially from renewable biomass.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Upcycling of waste gases such as CO2 to useful and valuable plastics has long been of interest, and the ROCP of epoxides and CO2 represents one of the most successful examples of CO2 utilization in polymer synthesis.

    “Upcycling of waste gases such as CO2 to useful and valuable plastics has long been of interest to researchers, and the ROCP of epoxides and CO2 represents one of the most successful examples of CO2 utilization in polymer synthesis.83,[344][345][346][347][348][349][350][351][352]”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [83] source

      Not checked in the free run.

    • cites [344] source

      Not checked in the free run.

    • cites [345] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Because 5CCs are thermodynamically stable and cannot be re-incorporated into the chains, this elimination causes irreversible loss of yield.

    “Because 5CCs are thermodynamically stable and cannot be re-incorporated into the chains, this elimination causes irreversible loss of yield.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    One appealing aspect of the ROCP approach is the common availability and structural diversity of epoxide and cyclic anhydride monomers, which can be easily prepared from olefins and dicarboxylic acids, respectively.

    “One appealing aspect of the ROCP approach is the common availability and structural diversity of epoxide and cyclic anhydride monomers, which can be easily prepared from olefins and dicarboxylic acids, respectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Chain propagation proceeds by the alternative insertion of epoxide and CO2 (or cyclic anhydride) to the metal-oxygen chain end, which leads to the desired formation of polycarbonate (or polyesters) backbones.

    “Chain propagation proceeds by the alternative insertion of epoxide and CO2 (or cyclic anhydride) to the metal-oxygen chain end, which leads to the desired formation of polycarbonate (or polyesters) backbones.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [344] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In most cases, a nucleophilic cocatalyst is used to increase the activity of the metal complexes, the most common ones being bis(triphenylphosphine) iminium salts and 4-dimethylaminopyridine.

    “In most cases, a nucleophilic cocatalyst is used to increase the activity of the metal complexes, the most common ones being bis(triphenylphosphine) iminium salts ([PPN]X) and 4-dimethylaminopyridine (DMAP).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [343] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The exploitation of chain transfer phenomenon enables immortal polymerization conditions, where chain transfer agents are added in large excess compared to the catalyst to increase the polymerization rate and control the molecular weight of products.

    “On the other hand, the exploitation of chain transfer phenomenon enables immortal polymerization conditions, where the chain transfer agents are added in large excess compared to the catalyst to increase the polymerization rate and control the molecular weight of products.360”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [360] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Some epoxides and anhydrides can be prepared from biomass such as limonene oxide (from terpene) and maleic anhydride (from furfuraldehyde), which are attractive monomers for fully renewable aliphatic polyesters and polycarbonates.

    “Some epoxides and anhydrides can be prepared from biomass (Figure 7) such as limonene oxide (from terpene) 365,366 and maleic anhydride (from furfuraldehyde) 138 , which are attractive monomers for fully renewable aliphatic polyesters and polycarbonates.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [365] source

      Not checked in the free run.

    • cites [366] source

      Not checked in the free run.

    • cites [138] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PHAs are produced by a variety of microorganisms as a carbon and energy storage material in times of unbalanced nutrient availability.

    “PHAs are produced by a variety of microorganisms as a carbon and energy storage material in times of unbalanced nutrient availability.376”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [376] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Collectively, heterotrophic bacteria have led to the biosynthesis of over 150 different types of PHA copolymers.

    “Collectively, these bacteria have led to the biosynthesis of over 150 different types of PHA copolymers.385”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [385] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Biological recycling is the longest path for building a circular flow of plastics, and the energy and environmental prices paid to build the chemical complexity of monomers are completely lost during the degradation processes.

    “However, this is the longest path for building a circular flow of the plastics (Scheme 17), and the energy and environmental prices paid to build the chemical complexity of monomers are completely lost during the degradation processes.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    Recycling is one of the most important end-of-use options to reduce the environmental impacts and resources depletion of plastics.

    “Recycling is one of the most important end-of-use options to reduce the environmental impacts and resources depletion of plastics.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    While efficient processes have been developed, sophisticated purification and process controls are needed to insure that hazardous substances are not released into the atmosphere during incineration.

    “In addition, while efficient processes have been developed, sophisticated purification and process controls are needed to insure that the hazardous substances are not released into the atmosphere.41”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [41] Francis R., 2017

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Depending on the organism and the conditions of growth, the molecular weight of PHBs can vary from 50,000 Da to over a million Da.

    “Depending on the organism and the conditions of growth, the molecular weight of PHBs can vary from 50,000 Da to over a million Da. 384”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [384] Bugnicourt E., 2015

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Methanotrophic bacteria that produce PHAs can be found at wastewater treatment plants, which are often geographically close to sources of waste methane.

    “The methanotrophic bacteria that produce PHAs can be found at wastewater treatment plants, which are often geographically close to sources of waste methane.375,381,382”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [375] source

      Not checked in the free run.

    • cites [381] source

      Not checked in the free run.

    • cites [382] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Many epoxides and cyclic anhydrides contain unsaturated moieties that can be utilized for post-polymerization modifications and crosslinking, which increases the range of architectures and functionalities achievable through the ROCP method.

    “Additionally, many epoxides and cyclic anhydrides contain unsaturated moieties that can be utilized for post-polymerization modifications and crosslinking, 211 which increases the range of architectures and functionalities that can be achieved through the ROCP method.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [211] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PHAs are an important class of biodegradable plastics commonly used for packaging, bottles, cutlery, furniture, biomedical implants, drug delivery vehicles, and animal food supplements.

    “PHAs are an important class of biodegradable plastics commonly used for packaging, bottles, cutlery, furniture, biomedical implants, drug delivery vehicles, and animal food supplements.[371][372][373][374]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [371][372][373][374]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Terpolymerization of epoxide, cyclic anhydride, and CO2 is a facile strategy for the one-pot synthesis of poly(ester-carbonate), a class of biodegradable polymers that have garnered considerable interest due to their possible superior properties than pure polyesters and polycarbonates.

    “Terpolymerization of epoxide, cyclic anhydride, and CO2 is a facile strategy for the onepot synthesis of poly(ester-carbonate), 211,343 a class of biodegradable polymers that have garnered considerable interest due to their possible superior properties than pure polyesters and polycarbonates.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [211] source

      Not checked in the free run.

    • cites [343] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The majority (>70%) of recycled PET (rPET) is used for production of lower-grade products, mainly polyester fibers, and only a small fraction (~10%) is used for closed-loop bottle-to-bottle recycling.

    “The majority (> 70%) of recycled PET (rPET) is used for production of lower-grade products, mainly polyester fibers, and only a small fraction (~10%) is used for closed-loop bottle-to-bottle recycling.394”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [394] Data from Noone A., Collected PET bottles, Proceedings of 13th International Polyester Recycling Forum, 2008.

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    According to the National Association for PET Container Resources (NAPCOR), ~30.1% PET plastic bottles were mechanically recycled in 2015 in the United States.

    “According to the National Association for PET Container Resources (NAPCOR), ~30.1% PET plastic bottles were mechanically recycled in 2015 in the United States.393”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [393] NAPCOR Recycling Rate Reports. http://www.napcor.com/PET/pet_reports.html(accessed May 8, 2017).

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Since the ability to substitute recycled plastic for virgin polymer depends on the purity of the recovered plastic feed, mechanical recycling of rigid plastic bottles consisting of a single polymer is much simpler and more economical than multi-layer and multi-component packages.

    “Since the ability to substitute recycled plastic for virgin polymer depends on the purity of the recovered plastic feed, mechanical recycling of rigid plastic bottles consisting of a single polymer are much simpler and more economical than those multi-layer and multi-component packages.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Since closed-loop mechanical recycling requires the polymers to be effectively separated from sources of contaminations and stable during reprocessing, the only postconsumer plastic wastes that have routinely been recycled in a closed-loop fashion are clear PET bottles and more recently HDPE bottles.

    “Since closed-loop mechanical recycling requires the polymers to be effectively separated from sources of contaminations (other plastics, metals, pigments, adhesives, etc.) and stable during reprocessing (grinding, melting), the only postconsumer plastic wastes that have routinely been recycled in a closed-loop fashion are clear PET bottles and more recently HDPE bottles.388”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [388] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    The most challenging step in mechanical recycling of PET is sorting/separation, which limits the type of polymers that can be recycled and also determines the quality of recyclates.

    “The most challenging step is sorting/ separation, which limits the type of polymers that can be recycled and also determines the quality of recyclates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    In the first step, PET was depolymerized using isosorbide to oligomers, which were chain extended by succinic acid in the second step to form a novel copolyester.

    “In the first step, PET was depolymerized using isosorbide to oligomers, which were chain extended by succinic acid in the second step to form a novel copolyester (Scheme 18).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [414] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Computational studies revealed that this reaction proceeds by the nucleophilic attack of the metal carbonate on the PC and the evolution of CO2 gas as the by-product.

    “Computational studies revealed that this reaction proceeds by the nucleophilic attack of the metal carbonate on the PC and the evolution of CO2 gas as the by-product.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [417] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The alcoholysis of PLAs have been achieved under different conditions and the efficiency of these processes is highly condition-dependent.

    “The alcoholysis of PLAs have been achieved under different conditions [433][434][435][436] and the efficiency of these processes is highly condition-dependent.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [433][434][435][436]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Monobutyltin oxide was identified as the most active catalyst for both steps and resulted in minimal discoloration.

    “Monobutyltin oxide was identified as the most active catalyst for both steps and resulted in minimal discoloration.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [415] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    These mechanisms are supported by the fact that when the OH chain end is capped via acetylation, the degradation rate significantly decreases and the relatively slow random chain scission become dominant.

    “These mechanisms are supported by the fact that when the OH chain end is capped via acetylation, the degradation rate significantly decreases and the relatively slow random chain scission become dominant.428”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [428] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Jung found that PPC was less susceptible to degradation in acidic medium than PCL and PLA, with increased degradation rate as PPC << PLA < PCL.

    “They found that PPC was less susceptible to degradation in acidic medium than PCL and PLA, with increased degradation rate as PPC << PLA < PCL.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [425] source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    Although the two mechanisms operate simultaneously during hydrolysis, several studies have found that the chain-end scission is significantly faster than the random backbone cleavage.

    “Although the two mechanisms operate simultaneously during hydrolysis, several studies have found that the chainend scission is significantly faster than the random backbone cleavage.424,426,427”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [424] source

      Not checked in the free run.

    • cites [426] source

      Not checked in the free run.

    • cites [427] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In contrast, PPC was more readily hydrolyzed in basic conditions, with increased degradation rate being PCL << PLA < PPC.

    “In contrast, PPC was more readily hydrolyzed in basic conditions, with increased degradation rate being PCL << PLA < PPC.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [425] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The rate of water diffusion depends on the hydrophobicity of the polymer and its shape or surface area while the intrinsic degradation kinetics is affected by the pH and temperature of the medium as well as the molecular weight and microstructures of the polymer.

    “The rate of water diffusion depends on the hydrophobicity of the polymer and its shape or surface area while the intrinsic degradation kinetics is affected by the pH 421 and temperature of the medium 422 as well as the molecular weight 423 and microstructures of the polymer.424”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [421] source

      Not checked in the free run.

    • cites [422] source

      Not checked in the free run.

    • cites [423] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    At acidic pH the hydrolysis proceeds through a preferential scission of the end groups and spits out one lactic acid unit at a time, while the base catalyzed hydrolysis proceeds preferentially via a backbiting process from the OH chain end leading to the formation of lactide, which is eventually hydrolyzed to lactate.

    “While at acidic pH the hydrolysis proceeds through a preferential scission of the end groups and spits out one lactic acid unit at a time, the base catalyzed hydrolysis proceeds preferentially via a backbiting process from the OH chain end leading to the formation of lactide, which is eventually hydrolyzed to lactate.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [421] source

      Not checked in the free run.

    • cites [424] source

      Not checked in the free run.

    • cites [428] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Computational investigation showed that stoichiometric amounts of metal carbonate is needed for the reaction to proceed to completion, but insights provided by investigating the mechanism also led them to develop a catalytic process using 12 mol% K2CO3 with lower reaction efficiency.

    “The computational investigation showed that stoichiometric amounts of metal carbonate is needed for the reaction to proceed to completion, but insights provided by investigating the mechanism also led them to develop a catalytic process using 12 mol% K2CO3 with lower reaction efficiency.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [417] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Acid- or base-catalyzed hydrolysis of aliphatic polyester and polycarbonates has also been widely explored, the results of which have been used to guide the design and application of these polymers for therapeutic delivery and medical implants.

    “The acid-or base-catalyzed hydrolysis of aliphatic polyester and polycarbonates has also been widely explored, the results of which have been used to guide the design and application of these polymers for therapeutic delivery and medical implants.418”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [418] Kumar M. N. V. R., 2016

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The use of Bu2Sn(OMe)2 or NaOH facilitated a nearly quantitative depolymerization to CL, while Ti(OiPr)4 gave almost equal amounts of CL and its cyclic dimer.

    “The use of Bu2Sn(OMe)2 or NaOH facilitated a nearly quantitative depolymerization to CL, while Ti(O i Pr)4 gave almost equal amounts of CL and its cyclic dimer.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [454] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    It was shown that both the depolymerization rate and selectivity increased with Sn concentration.

    “It was shown that both the depolymerization rate and selectivity increased with Sn concentration.[447][448][449]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [447][448][449]

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Acetylation of the OH chain end significantly increased the polymer stability and impeded the thermal recycling, consistent with an unzipping mechanism initiated from the OH chain end.

    “Acetylation of the OH chain end significantly increased the polymer stability and impeded the thermal recycling, consistent with an unzipping mechanism initiated from the OH chain end.444”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [444] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    For Sn < 20 ppm, the degradation proceeded mainly via random intra- and intermolecular ester exchange, generating a significant amount of diastereomers and cyclic oligomers.

    “For Sn < 20 ppm, the degradation proceeded mainly via random intra-and intermolecular ester exchange, generating a significant amount of diastereomers and cyclic oligomers.448”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [448] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Compared to the traditional bulk production of lactate esters based on the esterification of lactic acid, these catalytic alcoholyses of PLAs provide a number of advantages, including starting materials derived from PLA wastes, reduced reaction time and high yield, simple purification, and retention of stereochemistry.

    “Compared to the traditional bulk production of lactate esters based on the esterification of lactic acid 441,442 , these catalytic alcoholyses of PLAs provide a number of advantages, including starting materials derived from PLA wastes, reduced reaction time and high yield, simple purification, and retention of stereochemistry.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [441] source

      Not checked in the free run.

    • cites [442] Martino-Gauchi, G.; Teissier, R.Continuous Esterification Process for the Preparation of Ethyl Lactate from Lactic Acid and Ethanol. U.S. Patent 20060041165 A1, 2004.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    However, this method exerts little control over the chain length of each block as the insertion of the diols to the PLA is random.

    “However, this method exerts little control over the chain length of each block as the insertion of the diols to the PLA is random.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [443] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Leibfarth reported a very efficient way to recycle PLAs and PGA to small esters using TBD as the catalyst; with only 1.5 equivalents of alcohol per ester bond, quantitative alcoholysis to small esters was observed in only 2 min at room temperature with nearly complete retention of stereochemistry.

    “Leibfarth reported a very efficient way to recycle PLAs and PGA to small esters using TBD as the catalyst.439 With only 1.5 equivalents of alcohol per ester bond, quantitative alcoholysis to small esters was observed in only 2 min at room temperature with nearly complete retention of stereochemistry.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [439] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The functional group tolerance of TBD allows the introduction of different polymerizable groups (e.g. olefin) to the ester products, which provides a number of opportunities in the production of new polymer materials.

    “The functional group tolerance of TBD allows the introduction of different polymerizable groups (e.g.olefin) to the ester products (Scheme 21), which provides a number of opportunities in the production of new polymer materials.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [439] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The presence of catalyst enables milder reaction conditions and among the screened metal catalysts, magnesium and calcium alkoxides generated in situ from the metallic precursors and alcohols gave the best yields (>90%) and negligible epimerization.

    “The presence of catalyst enables milder reaction conditions and among the screened metal catalysts, magnesium and calcium alkoxides generated in situ from the metallic precursors and alcohols gave the best yields (>90%) and negligible epimerization.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [440] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In the early 1990s, Du Pont developed a method using 2-3 equiv. of alcohol per polymer unit at 150-190 °C with H2SO4 as the catalyst, achieving 69-87% conversion of high-molecular-weight PLA to lactates within 2 h.

    “In the early 1990s, Du Pont developed a method using 2-3 equiv. of alcohol (ROH for R = Me, Et, Bu) per polymer unit at 150-190 °C with H2SO4 as the catalyst.69-87% conversion of high-molecular-weight PLA to lactates is achieved within 2 h.437,438”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [437] Brake, L. D.Recovery of polyhydroxy acids. U.S. Patent 5264614 A, 1993.

      Not checked in the free run.

    • cites [438] Brake, L. D.Preparation of alkyl esters by depolymerization of poly(hydroxy acids). U.S. Patent 5264617 A, 1993.

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In contrast, for samples with Sn > 480 ppm, the degradation kinetics indicated an unzipping depolymerization mechanism along with minor bimolecular transesterification reactions, leading to the predominant production of L-LA.

    “In contrast, for samples with Sn > 480 ppm, the degradation kinetics indicated an unzipping depolymerization mechanism along with minor bimolecular transesterification reactions, leading to the predominant production of L-LA.448,449”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [448] source

      Not checked in the free run.

    • cites [449] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    In general, substituted lactones have relatively low polymerizability compared to the unsubstituted ones and are thus potential candidates for thermal recycling.

    “In general, substituted lactones have relatively low polymerizability compared to the unsubstituted ones and are thus potential candidates for thermal recycling.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [274] source

      Not checked in the free run.

    • cites [275] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The topologies of the products can be controlled by the La[N(SiMe3)2]3/ROH ratios, with excess ROH favoring the formation of linear chains.

    “The topologies of the products can be controlled by the La[N(SiMe3)2]3/ROH ratios, with excess ROH favoring the formation of linear chains.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [278] source

      Not checked in the free run.

    • cites [460] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Using similar conditions (-60 °C, Ln/ROH = 1/3) to that of γ-BL, they were able to achieve the selective ROP of MBL to produce poly(MBL) with Mn up to 21 kDa, which can be facilely recycled back to the monomer MBL by heating the polymer ≥ 100 °C for 1 h in the presence of catalysts.

    “Using similar conditions (-60 °C, Ln/ROH = 1/3) to that of γ-BL, they were able to achieve the selective ROP of MBL to produce poly(MBL) with Mn up to 21 kDa, which can be facilely recycled back to the monomer MBL by heating the polymer ≥ 100 °C for 1 h in the presence of catalysts.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [177] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Polymers made from monomers with low polymerization enthalpy are intrinsically unstable and tend to degrade under environmental stresses such as heat or moisture.

    “Second, the polymers are intrinsically unstable and tend to degrade in the environmental stresses such as heat or moisture.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    At -40 °C and ambient pressure, the ROP of γ-BL proceeded smoothly in the presence of a catalyst (La[N(SiMe3)2]3 or tert-Bu-P4) to high conversions within 24 h, generating poly(γ-BL) with Mn up to 30 kDa and Ð ~ 2.0.

    “At -40 °C and ambient pressure, the ROP of γ-BL proceeded smoothly in the presence of a catalyst (La[N(SiMe3)2]3 or tert-Bu-P4) to high conversions within 24 h, generating poly(γ-BL) with Mn up to 30 kDa and Ð ~ 2.0.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [278] source

      Not checked in the free run.

    • cites [460] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Based on this chemistry, they developed chemically recyclable thermoplastic polyurethanes and novel polyester elastomers.

    “Based on this chemistry, they developed chemically recyclable thermoplastic polyurethanes 161 and novel polyester elastomers 162 .”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [161] source

      Not checked in the free run.

    • cites [162] source

      Not checked in the free run.

  • The quote only partly states this claim.

    Interpretationreasoning

    Performing polymerization and processing at low temperature increases the energy cost of the products.

    “This increases the energy cost of the products.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The presence of catalyst allowed pyrolysis to be conducted at lower temperature than without a catalyst and suppressed the formation of oligomeric species.

    “The presence of catalyst not only allowed the pyrolysis to be conducted at lower temperature than without a catalyst, but also suppressed the formation of oligomeric species.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [466] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    The Lewis acidic nature of Ca2+ and Mg2+ facilitates activation of the six-membered transition state in the unzipping depolymerization of PHA, leading to more selective degradation than in the absence of catalysts.

    “It is proposed that the Lewis acidic nature of Ca 2+ and Mg 2+ facilitates the activation of the six-membered transition state in the unzipping depolymerization of PHA (Scheme 23), and thus leads to a more selective degradation process than in the absence of catalysts.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Catalytic pyrolysis using Mg(OH)2 as the catalyst was used to recycle a variety of short- and medium-chain length PHAs and proved the utility of the recovered monomers as feedstocks for microbial synthesis of PHAs.

    “This catalytic pyrolysis strategy (using Mg(OH)2 as the catalyst) was used to recycle a variety of short-and medium-chain length PHAs and further proved the utility of the recovered monomers as feedstocks for the microbial synthesis of PHAs.375,381”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [375] source

      Not checked in the free run.

    • cites [381] source

      Not checked in the free run.

  • May combine two claims.

    Premisereasoning

    Because most aliphatic polyesters and polycarbonates are hydrophobic, enzymes exhibit a substrate binding domain (SBD) in addition to their catalytic domain, which facilitates adsorption of the enzyme on water-insoluble polymers.

    “Since most aliphatic polyesters and polycarbonates are hydrophobic, enzymes exhibit a substrate binding domain (SBD) in addition to their catalytic domain, which facilitates the adsorption of the enzyme on the water-insoluble polymers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    When cell extracts are used to depolymerize water-insoluble polymers, only steps 2 and 3 are observed.

    “Noteworthy, when cell extracts are used to depolymerize water-insoluble polymers, only steps 2 and 3 are observed (see Figure 14).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Mineralization of PHVB was faster in fertile soil than with isolated enzymes, owing to a more diverse population of degrading enzymes in the soil.

    “For instance, the mineralization of PHVB was shown to be faster in fertile soil vs. isolated enzymes, owing to a more diverse population of degrading enzymes in the soil.484”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [484] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Overall, anaerobic microbial degradation of aliphatic polyesters and polycarbonates remains poorly studied, despite advantages such as high efficiency, especially for PLA and PHAs, and fast rates.

    “Overall, anaerobic microbial degradation of aliphatic polyesters and polycarbonates remains poorly studied, despite several advantages such as high efficiency, especially for PLA and PHAs, and fast rates.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    When chains are short enough to be soluble in the media and cross the membrane, further degradation/digestion might take place with the help of intracellular enzymes.

    “When the chains are short enough to be soluble in the media and cross the membrane, further degradation/digestion might take place with the help of intracellular enzymes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The rate of degradation was faster for PLA nanocomposites than for pure PLA, owing to the presence of hydroxyl moieties at the surface of nanoclay that can act as nucleophiles.

    “Moreover, the rate of degradation was found to be faster for PLA nanocomposites than for pure PLA, owing to the presence of hydroxyl moieties at the surface of nanoclay that can act as nucleophiles.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [488] source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    High molar mass polymers are unable to penetrate the membrane of microbial organisms and so are not susceptible to microbial attack by intracellular enzymes as such.

    “High molar masses polymers are unable to penetrate the membrane of microbial organisms, and so are not susceptible to microbial attack by intracellular enzymes as such.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisereasoning

    Because the microorganism has access to O2 in aerobic conditions, the end products of mineralization are CO2 and H2O, instead of CO2 and CH4 in anaerobic conditions.

    “Because the microorganism has access to O2 in aerobic conditions, the endproducts of mineralization are CO2 and H2O, instead of CO2 and CH4 in anaerobic conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    PCL and PHB could also be biodegraded in similar settings, up to 90% degradation after 14 days for PHB, while PBS remained mostly intact, 3% degradation after 96 days.

    “PCL and PHB could also be biodegraded in similar settings (up to 90% degradation after 14 days for PHB), while PBS remained mostly intact (3% degradation after 96 days).478”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [478] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    PLA and PLLA could be degraded by soil bacteria in aquatic conditions, up to 90% after 60 days for PLA and 50% after 40 days for PLLA.

    “showed that PLA and PLLA, respectively, could be degraded by soil bacteria in aquatic conditions (up to 90% after 60 days for PLA and 50% after 40 days for PLLA).[477][478][479]”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [477] source

      Not checked in the free run.

    • cites [478] source

      Not checked in the free run.

    • cites [479] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Considerable efforts have been focused on biodegradable polymers that can be decomposed naturally or in composting sites by microorganisms.

    “Considerable efforts have been focused on biodegradable polymers that can be decomposed naturally or in composting sites by microorganisms.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Recently, catalytic systems that enable control of polymerization on a more sophisticated level such as architectures and monomer sequences are emerging.

    “Recently, catalytic systems that enable the control of polymerization on a more sophisticated level such as architectures and monomer sequences are emerging.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    The end products of biodegradable polymers are primarily CO2, H2O, and other metabolites that can re-enter the life cycle.

    “The end products are primarily CO2, H2O, and other metabolites that can re-enter the life cycle.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Metal-based catalysts are in general more competent in tackling the aforementioned challenges.

    “While metal-based catalysts are in general more competent in tackling the aforementioned challenges, organocatalysts have emerged as an efficient alternative.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Thermally recyclable polymers can be depolymerized to their monomers in high yields and reused to produce virgin quality polymers.

    “An emerging frontier in sustainable polymers is the design and synthesis of thermally recyclable polymers that can be depolymerized to their monomers in high yields, which can then be reused to produce virgin quality polymers.23”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationnone given

    Data to assess the environmental impacts or sustainability of catalysts are incomplete.

    “While a variety of active and selective catalysts are available for converting renewable monomers into well-defined polymers, data to assess their environmental impacts or sustainability are incomplete.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    Aliphatic polyesters and aliphatic polycarbonates can be repurposed to versatile synthetic intermediates or environmentally degraded if they end up in the environment.

    “Among the potentially sustainable alternatives to current commodity plastics, aliphatic polyesters and aliphatic polycarbonates are highlighted as they can be derived from renewable resources, they can be produced by a variety of versatile synthetic methods, they exhibit a wide range of useful properties and can be repurposed to versatile synthetic intermediates or environmentally degraded if they”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    Aliphatic polyesters and aliphatic polycarbonates exhibit a wide range of useful properties.

    “Among the potentially sustainable alternatives to current commodity plastics, aliphatic polyesters and aliphatic polycarbonates are highlighted as they can be derived from renewable resources, they can be produced by a variety of versatile synthetic methods, they exhibit a wide range of useful properties and can be repurposed to versatile synthetic intermediates or environmentally degraded if they”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    Catalysis is an enabling science that impacts every step of the plastics life cycle.

    “Catalysis is an enabling science that impacts every step of the plastics life cycle.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    Addition of organic solvents is advantageous to solubilization of polymers but can have a detrimental effect on the stability of the enzyme.

    “The addition of organic solvents is advantageous to the solubilization of the polymers but can have a detrimental effect on the stability of the enzyme.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    Aliphatic polyesters and aliphatic polycarbonates can be produced by a variety of versatile synthetic methods.

    “Among the potentially sustainable alternatives to current commodity plastics, aliphatic polyesters and aliphatic polycarbonates are highlighted as they can be derived from renewable resources, they can be produced by a variety of versatile synthetic methods, they exhibit a wide range of useful properties and can be repurposed to versatile synthetic intermediates or environmentally degraded if they”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Significant progress has been made in increasing catalytic activity (turnover frequency), productivity (turnover number), selectivity toward desired product formation over side reactions, and regio- or stereoselectivity.

    “Significant progress has been made in increasing the catalytic activity (turnover frequency), productivity (turnover number), selectivity toward desired product formation over side reactions, regio-or stereoselectivity.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Use of a proper catalyst allows milder depolymerization conditions and can improve the selectivity of depolymerization reactions.

    “It will be seen from the examples below that the use of a proper catalyst not only allows milder depolymerization conditions but can also improve the selectivity of depolymerization reactions.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Lipases are thought to only trigger esterification and transesterification reactions in dry organic solvents, while the presence of water allows hydrolysis.

    “Lipases are thought to only trigger esterification and transesterification reactions in dry organic solvents, while the presence of water allows for hydrolysis.514”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [514] source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Although the biodegradable end-of-life option mitigates some issues associated with indiscriminate disposal of plastics in the environment, it is not the only or even best option for capturing value.

    “Although this end-of-life option mitigates some of the issues associated with indiscriminate disposal of plastics in the environment, it is not the only or even best option for capturing value.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisenone given

    Overall PCL degrades fastest with quantitative depolymerization obtained with Pseudomonas lipase after 4 days in aqueous media, and addition of PLA or PPC to PCL greatly decreases this rate.

    “Overall PCL degrades the fastest with quantitative depolymerization obtained with Pseudomonas lipase after 4 days in aqueous media and, the addition of PLA or PPC to PCL greatly decreases this rate.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Traces of H2O in sCO2 (18 MPa) triggered formation of dicaprolactone from PCL in yields higher than 90%, allowing a full recycling cycle.

    “In contrast, traces of H2O in sCO2 (18 MPa), triggered the formation of dicaprolactone (i.e.1,8dioxacyclotetradecane-2,9-dione) from PCL in yields higher than 90%, therefore allowing for a full recycling cycle.520”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [520] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Some sustainability metrics and indicators such as green design principles can be used to assess different catalytic methods based on their adherence to green design principles.

    “Nevertheless, some sustainability metrics and indicators such as green design principles can be used to assess different catalytic methods based on their adherence to green design principles.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Economic disincentives have contributed to the modest rates of recycling and material recovery.

    “The end-of-life options of plastics are critical for the development of circular plastics economies, but economic disincentives have contributed to the modest rates of recycling and material recovery.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Economic disincentives have contributed to the modest rates of recycling and material recovery.

  • May combine two claims.

    Premisecitation

    Wei, Li et al. showed that proteinase K degraded PLLA faster than PDLA, mostly owing to higher adsorption of the enzyme at the surface of PLLA as compared to PDLA.

    “However, Wei, Li et al. showed that proteinase K degraded PLLA faster than PDLA, mostly owing to higher adsorption of the enzyme at the surface of PLLA as compared to PDLA.527”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [527] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Vert et al. showed that Pseudomonas lipase could break down the crystalline domains of PCL within days, in contrast to hydrolytic degradation that would take several years.

    “Noteworthy, Vert et al. showed that Pseudomonas lipase could break down the crystalline domains of PCL within days in contrast to hydrolytic degradation that would take several years to do the same.504”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [504] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Acetone allowed faster degradation and DMSO was the less efficient solvent, evidencing that overall the depolymerization rate increased with higher solvent polarity and lower solvent viscosity.

    “Acetone allowed for the faster degradation and DMSO was the less efficient solvent, evidencing that overall, the depolymerization rate increased with higher solvent polarity and lower solvent viscosity.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [516] source

      Not checked in the free run.

    • cites [517] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Proteinase K is stable in the 8-8.6 pH range and is particularly efficient to degrade PLA.

    “Proteinase K is stable in the 8-8.6 pH range and is particularly efficient to degrade PLA.523,524”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [523] source

      Not checked in the free run.

    • cites [524] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Depolymerase and esterase could digest inclusion bodies of Bacillus megaterium containing PHB to produce D(-)-β-hydroxybutyric ester, with up to 90% hydrolysis after 100 min.

    “depolymerase”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [469] Merrick J. M., 1964, J. Bacteriol. source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    PHA depolymerases usually exhibit a catalytic domain containing an esterase sequence (often similar to lipase) and a substrate-binding domain (SBD) to enable adsorption of the enzyme at the surface of hydrophobic PHAs.

    “PHA depolymerases usually exhibit a catalytic domain containing an esterase sequence -often similar to lipase -and a substrate-binding domain (SBD) to enable adsorption of the enzyme at the surface of hydrophobic PHAs.493”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [493] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Several PHA depolymerases have been isolated mainly from Alcaligenes, Pseudomonas, and Comamonas, and their structures and properties have been extensively reviewed.

    “Since this first report, several PHA depolymerases have been isolated on agar plates, mainly from Alcaligenes, Pseudomonas and Comamonas and their structures and properties have been extensively reviewed.491,492”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [491] source

      Not checked in the free run.

    • cites [492] source

      Not checked in the free run.

218 of 218

  • The authors state this as an assumption.

    The definition of sustainable polymers as materials with closed-loop life cycles is adopted as an aspirational goal.

    “We have adopted this definition as an aspirational goal in the spirit of sustainable development.”

  • The paper relies on this without support.

    Cellulose and hemicellulose can provide an almost unlimited source of C5 and C6 sugars if efficient strategies are devised to recover and purify these feedstocks effectively.

    “The two major components of lignocellulose, cellulose and hemicellulose, provide an almost unlimited source of C5 and C6 sugars, provided efficient strategies can be devised to recover and purify these feedstocks effectively.”

  • The paper relies on this without support.

    Identifying the best pathway to convert a given feedstock to a given monomer is one of the first challenges for the development of sustainable polymers.

    “Identifying the best pathway to convert the aforementioned feedstock to a given monomer is one of the first challenges for the development of sustainable polymers.”

  • The paper relies on this without support.

    Economic disincentives have contributed to the modest rates of recycling and material recovery.

    “economic disincentives have contributed to the modest rates of recycling and material recovery.”

  • The paper relies on this without support.

    Direct pyrolysis cannot achieve monomer recovery for step-growth polyesters and polycarbonates.

    “While monomer recovery cannot be achieved through direct pyrolysis for step-growth polyesters and polycarbonates, this is an attractive recycling option for chain-growth polymers.”

  • The paper relies on this without support.

    Direct pyrolysis is an attractive recycling option for chain-growth polymers.

    “While monomer recovery cannot be achieved through direct pyrolysis for step-growth polyesters and polycarbonates, this is an attractive recycling option for chain-growth polymers.”

  • The paper relies on this without support.

    Plastic sorting and tolerance to contaminants in plastics feeds presents a significant challenge for chemical recycling.

    “Similar to mechanical recycling, plastic sorting and tolerance to contaminants in the plastics feeds presents a significant challenge for chemical recycling.”
7 of 7

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Cites

Flagged first, then by citations

5 of the 475 references couldn’t be matched to a known paper.

Research works printed but not linked: 17

  1. Francis R., 2017, Recycling of Polymers: Methods, Characterization and Applications
  2. Valuing Plastic: The Business Case for Measuring, Managing and Disclosing Plastic Use in the Consumer Goods Industry, 2014, United Nations Environment Programme (UNEP).http://hdl.handle.net/20.500.11822/9238(accessed August 5, 2017).
  3. Kaenzig, J.; H, G.; Rocher, M.Proceedings of the 2nd World Conference and Technology Exhibition on Biomass For Energy, Industry and Climate Change, Rome, Italy, 2004.
  4. 10.1039/c3py01213a · DOI · Paper page
  5. Werpy T., 2004, Top Value Added Chemicals from Biomass. Vol. I - Results of Screening for Potential Candidates from Sugars and Synthesis Gas
  6. Kassaian J.-M., 2002, Ullmann’s Encyclopedia of Industrial Chemistry
  7. Sivasankaran C., 2016, J. Env. Biol., 37, 1539
  8. 2008, Biodiesel from Triglycerides via Transesterification
  9. 10.1039/b922014c · DOI · Paper page
  10. Wang L. S., 2005, Chin. Chem. Lett., 16, 572
  11. 10.1002/macp.201200332 · DOI · Paper page
  12. 10.1039/c5py01843a · DOI
  13. 10.1021/ma200685u · DOI · Paper page
  14. Dove A. P., 2009, Handbook of Ring-Opening Polymerization
  15. Data from Noone A., Collected PET bottles, Proceedings of 13th International Polyester Recycling Forum, 2008.
  16. Genta, M.; Yano, F.; Kondo, Y.; Matsubara, W.; Oomoto, S.Technical Review;Mitsubishi Heavy Industries, Ltd., 2003, Vol.40, pp1–4.
  17. 10.1073/pnas.1404596111 · DOI · Paper page

Cited by

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Related

Authors
Zhang, X., Fevre, M., Jones, G. O., & Waymouth, R. M.
Affiliations
  • Stanford University (US)
  • IBM Research−Almaden, 650 Harry Road, San Jose, California 95120, United States
  • IBM Research - Almaden (US)
Corresponding author
Waymouth, Robert M.
ORCID
Venue
Chemical Reviews
Publisher
American Chemical Society (ACS)
Published
2017-10-19
Volume
118
Issue
2
Pages
839-885
ISSN
  • 0009-2665 (ISSN-L)
  • 1520-6890
DOI
10.1021/acs.chemrev.7b00329
OpenAlex
W2765471533
Semantic Scholar
cee5814ab26e29aa779b2c3b6eaac0d596cea68a
Cited by
936
References
475
Citations by year
2026: 63 · 2025: 106 · 2024: 116 · 2023: 131 · 2022: 141 · 2021: 127 · 2020: 118 · 2019: 77 · 2018: 55 · 2017: 1
FWCI
4.97
Type
journal article
Language
en
Open access
Locations
  • Chemical Reviews (publishedVersion)
  • PubMed (publishedVersion)
  • OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (submittedVersion)
Funders
  • Division of Chemistry (CHE-1607092)
  • LAM Foundation
  • Stanford University
  • U.S. Department of Energy (DE-SC0005430)
Topics
  • Physical Sciences › Materials Science › Biomaterials › biodegradable polymer synthesis and properties
  • Physical Sciences › Chemical Engineering › Process Chemistry and Technology › Carbon dioxide utilization in catalysis
  • Physical Sciences › Materials Science › Polymers and Plastics › Polymer crystallization and properties
Keywords
sustainable polymers, catalysis, renewable raw materials, aliphatic polyesters, polycarbonate, renewable monomers, biodegradable polymers, polymer synthesis, biocatalysis

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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