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Cited by 34Hygrothermal properties of building materialsPolymer Foaming and CompositesBuilding energy efficiency and sustainability

Research of Wood Waste as a Potential Filler for Loose-Fill Building Insulation: Appropriate Selection and Incorporation into Polyurethane Biocomposite Foams

Open access
Augaitis, Nerijus, Vaitkus, Saulius, Członka, Sylwia, Kairytė, Agnė·2020·Materials
DOI 10.3390/ma13235336PMC PMC7728156
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Abstract

Currently, the recycling potential of wood waste (WW) is still limited, and in a resource efficiency approach, recycling WW in insulation materials, such as polyurethane (PUR), appears as an appropriate solution. It is known that the quality of WW is the main aspect which influences the stability of the final products. Therefore, the current study analyses different WW-based fillers as possible modifiers for polyurethane biocomposite foams for the application as loose-fill materials in building envelopes. During the study of WW-based fillers, it was determined that the most promising filler is wood scobs (WS) with a thermal conductivity of 0.0496 W/m·K, short-term water absorption by partial immersion—12.5 kg/m2, water vapour resistance—0.34 m2·h·Pa/mg and water vapour diffusion resistance factor—2.4. In order to evaluate the WS performance as a filler in PUR biocomposite foams, different ratios of PUR binder and WS filler (PURb/WS) were selected. It was found that a 0.40 PURb/WS ratio is insufficient for the appropriate wetting of WS filler while a 0.70 PURb/WS ratio produced PUR biocomposite foams with the most suitable performance: thermal conductivity reduced from 0.0523 to 0.0476 W/m·K, water absorption—from 5.6 to 1.3 kg/m2, while the compressive strength increased from 142 to 272 kPa and the tensile strength increased from 44 to 272 kPa.

AI snapshot

Written from the paper’s full text.

TL;DR

This study screened five wood-waste fillers and selected cleaned pinewood sawdust (WS) as the most promising filler for loose-fill polyurethane biocomposite foams. A 0.70 PURb/WS ratio gave the best overall insulation performance, while 0.40 was insufficient for wetting and 0.85 caused excessive blowing and cell damage.

Key findings

  • Among the WW-based fillers, WS had thermal conductivity 0.0496 W/m·K, short-term water absorption by partial immersion 12.5 kg/m², water vapour resistance 0.34 m²·h·Pa/mg, and water vapour diffusion resistance factor 2.4; WB showed the highest thermal conductivity.
  • The 0.70 PURb/WS ratio produced the most suitable foam performance: apparent density 150 kg/m³, thermal conductivity 0.0476 W/m·K, tensile strength 272 kPa, short-term water absorption 1.3 kg/m², water vapour resistance 1.66 m²·h·Pa/mg, and water vapour diffusion resistance factor 26.
  • The abstract reports that at 0.70 PURb/WS, thermal conductivity reduced from 0.0523 to 0.0476 W/m·K and water absorption from 5.6 to 1.3 kg/m², while compressive strength increased from 142 to 272 kPa and tensile strength from 44 to 272 kPa; the conclusions list the 0.70 foam’s compressive strength as 220 kPa.
  • A 0.40 PURb/WS ratio gave insufficient wetting, voids, and open pores, while 0.85 caused excessive blowing, lower closed-cell content, and on average 74% higher cell size compared with 0.70 PURb/WS.

Methods

  • Five WW-based fillers were tested: uncleaned pinewood sawdust (uWS), cleaned pinewood sawdust (WS), pinewood bark (WB), Lithuanian hemp shives (HS-LT), and French hemp shives (HS-FR); characterisation included bulk density, moisture content, thermal conductivity, SEM, long-term water absorption by partial immersion, and water vapour permeability.
  • PUR biocomposite foams were prepared with rapeseed polyol, polymeric 4,4-diphenylmethane diisocyanate, surfactant, and catalyst at PURb/WS ratios of 0.40, 0.55, 0.70, and 0.85; testing covered apparent density, thermal conductivity, compressive and tensile strength, closed-cell content, microstructure, short-term water absorption, water vapour permeability, and dimensional stability.
  • Regression equations were fitted for water absorption of the WW fillers and for apparent density and thermal conductivity of the PUR biocomposite foams.

Limitations

  • The paper states there is a lack of information about short-term water absorption by partial immersion of various polymer-based biocomposite foams, making comparison of those values difficult.
  • The paper states the dimensional stability test duration was only 2 days, although it notes similar conclusions have been reported after 14 days of exposure.
  • Evident from the text: after filler screening, only WS was incorporated into PUR foams, so the other WW-based fillers were not tested in the final biocomposite foam formulations.

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

Integrity signals

Registry

Crossref · 10.3390/ma13235336

Cites

57 of 57 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

9 of 42 cited sources checked · 6 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    The WB filler has the lowest possible porosity (~60 vol.%) compared to WS (~78 vol.%) and HS (~77 vol.%) fillers.

    “the WB filler has the lowest possible porosity (~60 vol.% [37]) compared to WS (~78 vol.% [38]) and HS (~77 vol.% [39]) fillers”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [37] Chen, 2012, A Two-stage wood chip-based biofilter system to mitigate odors from a deep-pit swine building, Appl. Eng. Agric. source
    • cites [38] Christianson, 2010, Technical Note: Hydraulic Property Derermination of Denitrifying Bioreactor Fill Media, Appl. Eng. Agric. source
    • cites [39] Jiang, 2018, Cell wall microstructure, pore size distribution and absolute density of hemp shiv, R. Soc. Open Sci. source
  • Premisecitation

    Bark is less hygroscopic than wood.

    “bark is less hygroscopic than wood”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [35] Tsalagkas, 2019, Thermal, physical and mechanical properties of surface overlaid bark-based insulation panels, Eur. J. Wood Wood Prod. source
  • Interpretationcitation

    PUR biocomposite foams may be comparable to commercially available ones only at 0.40-0.55 PURb/WS ratios (≥250 kPa).

    “This shows that the PUR biocomposite foams may be comparable to commercially available ones only at 0.40–0.55 PURb/WS ratios (≥250 kPa) [54].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [54] Borowicz, M., Paciorek-Sadowska, J., Lubczak, J., and Czupryński, B. (2020). Biodegradable, flame-retardant, and bio-based rigid polyurethane/polyisocyanurate foams for thermal insulation application. Polymers, 11. source

      Section 3.2 (page unavailable) says the studied foams had compressive strength above 250 kPa and remained satisfactory compared with commercial materials. It does not give a 0.40–0.55 PURb/WS range or say that comparability is limited to those ratios; the study concerns mustard-seed-oil-based RPU/PIR foams. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Findingown data

    For PUR biocomposite foams, tensile strength increased from 44 to 272 kPa when the PURb/WS ratio changed from 0.40 to 0.70.

    “tensile strength increased from 44 to 272 kPa”
    Quote in the paperSubstantial claim
  • Findingown data

    For PUR biocomposite foams, water absorption reduced from 5.6 to 1.3 kg/m2 when the PURb/WS ratio changed from 0.40 to 0.70.

    “water absorption—from 5.6 to 1.3 kg/m2”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 21
  • May combine two claims. 35

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

    Premisecitation

    The future potential of wood waste recycling is quite low, mainly lacking sustainable reuse or recycling applications.

    “the future potential of WW recycling is quite low, mainly lacking sustainable reuse or recycling applications”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [4] Kern, 2018, Factors influencing temporary wood waste generation in high-rise building construction, Waste Manag. source
    • cites [5] Ramage, 2017, The wood from the trees: The use of timber in construction, Renew. Sustain. Energy Rev. source

      Section 8.3.1 describes multiple reuse and recycling applications and reports that UK wood-waste recycling reached 40–45%, concluding that recycled wood can be considered a resource rather than a waste product. Section 8.3 also identifies wood-plastic composites and fibreboard panels as uses for construction timber after its first service life. These passages run contrary to the claim that recycling potential is quite low mainly because sustainable applications are lacking. (LLM, conf=0.90)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

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

    Premisecitation

    Similar observations of tensile strength improvement were reported for microcellular polyurethane with sisal fibres and waterborne polyurethane with cellulose reinforcement.

    “Similar observations were reported in Reference [55], where microcellular polyurethane with sisal fibres were investigated, and in Reference [56], where research was conducted on waterborne polyurethane with cellulose reinforcement.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [55] Abdel-Hamid, S.M.S., Al-Qabandi, O.A., Elminshawy, N.A.S., Bassyouni, M., Zoromba, M.S., Abdel-Aziz, M.H., Mira, H., and Elhenawy, Y. (2019). Fabrication and characterization of microcellular polyurethane sisal biocomposires. Molecules, 24. source
    • cites [56] Zhang, 2020, Role of cellulose-based composite materials in synergistic reinforcement of environmentally friendly waterborne polyurethane, Prog. Org. Coat. source

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

    Premisecitation

    The water vapour diffusion resistance factor of wood-based products increased with increasing density.

    “the water vapour diffusion resistance factor of the wood-based products increased with increasing density”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [36] Sonderegger, 2009, Thermal conductivity and water vapour transmission properties of wood-based materials, Eur. J. Wood Wood Prod. source

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

    Premisecitation

    The European Union generates more than 50 million m3 of wood waste each year.

    “the European Union generates more than 50 million m3 of WW each year”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [2] Bergeron, 2016, Energy and climate impact assessment of waste wood recovery in Switzerland, Biomass Bionenergy source
    • cites [3] Berger, 2020, The recycling potential of wood waste into wood-wool/cement composite, Constr. Build. Mater. source

      The Introduction (page not provided) reports an estimate of 50 million cubic meters of wood waste generated each year in the European Union. It does not say the amount is more than 50 million cubic meters. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

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

    Premisecitation

    Alkaline treatment at an 8% concentration improved interfacial adhesion between hemp fibre and the PUR matrix.

    “Alkaline treatment was shown to be successful for hemp fibres, an 8% concentration showed an improvement in interfacial adhesion between the hemp fibre and the PUR matrix [11].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [11] Sair, 2017, Effect of surface modification on morphological, mechanical and thermal conductivity of hemp fiber: Characterization of the interface of hemp–polyurethane composite, Case Stud. Therm. Eng. source

  • May combine two claims.

    Findingnone given

    The pore sizes of uWS and WS are 10-20 μm with approximately ~2 μm-sized pits located in the tracheid walls.

    “The pore sizes of uWS and WS are of 10–20 μm with approximately ~2 μm-sized pits located in the tracheid’s walls.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    uWS and WS particles show the traditional structure of wood with hollow lumen spaces visible in cross-section and numerous pits across longitudinal areas.

    “uWS and WS particles show the traditional structure of wood with hollow lumen spaces which are visible in the cross-section, and numerous pits across longitudinal areas.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingreasoning

    For 0.85 PURb/WS, some cell walls cannot withstand the pressure during excessive blowing, thus reducing the overall closed cell content and the thermal conductivity by approximately 19% and 13%, compared to 0.70 PURb/WS.

    “some of the cell walls cannot withstand the pressure during excessive blowing, thus reducing the overall closed cell content and the thermal conductivity by approximately 19% and 13%, as compared to 0.70 PURb/WS”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The determination coefficients for apparent density and thermal conductivity are 0.959 and 0.966, respectively.

    “The obtained data show that the determination coefficients for apparent density and thermal conductivity are 0.959 and 0.966, respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The use of a 0.85 PURb/WS ratio determines on average a 74% higher cell size compared to a 0.70 PURb/WS ratio and shifts the cell size distribution curve towards higher sizes.

    “the use of a 0.85 PURb/WS ratio determines by, on average, a 74% higher cell size compared to a 0.70 PURb/WS ratio and shifts cell size distribution curve towards higher sizes”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The lowest tensile strength is obtained at 0.40 PURb/WS while 0.70 PURb/WS gives the highest value of tensile strength.

    “It can be seen that the lowest tensile strength is obtained at 0.40 PURb/WS while 0.70 PURb/WS gives the highest value of the parameter”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    In the case of 0.40-0.70 PURb/WS ratios, the cellular structure is quite well preserved, and the reduction in cell size is visible.

    “In the case of 0.40–0.70 PURb/WS ratios, the cellular structure is quite well preserved, and the reduction in cell size is visible”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    With the addition of PURb, the tensile strength increased by 621% compared to 0.40 PURb/WS, giving an average value of 272 kPa.

    “with the addition of PURb, the tensile strength increased by 621% compared to 0.40 PURb/WS, giving an average value of 272 kPa”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The lowest and the highest ratios of PURb/WS determined PUR biocomposite foams with the lowest volumetric content of closed cells, approximately 50 vol.%, while 0.70 PURb/WS biocomposite foam reached almost 70 vol.%.

    “the lowest and the highest ratios of PURb/WS determined the PUR biocomposite foams with the lowest volumetric content of closed cells, i.e., approximately 50 vol.%, while 0.70 PURb/WS biocomposite foam reached almost 70 vol.%”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    With increasing ratio of PURb/WS, the overall cell structure becomes less uniform and the number of broken cells is increased.

    “With the increasing ratio of PURb/WS, the overall cell structure becomes less uniform and the number of broken cells is increased.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The interface interaction between the porous polyurethane matrix and WS particles is not even, is full of voids and flaws, which increases the percentage of open pores and reduces the percentage of closed ones.

    “the interface interaction between the porous polyurethane matrix and WS particles is not even, it is full of voids and flaws which increases the percentage of open pores and reduces the percentage of closed ones”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    PUR biocomposite foams at a 0.70 PURb/WS ratio are characterised by a more regular structure with a lower content of open cells compared to PUR biocomposite foams at a 0.40 PURb/WS ratio.

    “PUR biocomposite foams at a 0.70 PURb/WS ratio are characterised by a more regular structure with a lower content of open cells compared to PUR biocomposite foams at a 0.40 PURb/WS ratio.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Compared to 0.40 PURb/WS, water absorption reduces by 20% for 0.55 PURb/WS, by 77% for 0.75 PURb/WS and by 90% for 0.85 PURb/WS ratios.

    “Compared to 0.40 PURb/WS, the parameter reduces by 20% for 0.55 PURb/WS, by 77% for 0.75 PURb/WS and by 90% for 0.85 PURb/WS ratios.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    WB particles have ~37-40% lignin, while WS has ~25%.

    “WB particles have ~37–40% lignin, while, e.g., WS has ~25% [34]”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [34] Revilla, 2015, Chemical characterization and fuel properties of wood and bark of two oaks from Oaxaca, Mexico, Ind. Crop. Prod. source

  • May combine two claims.

    Interpretationown data

    The increase in tensile strength indicates improved interfacial adhesion and improved stress transfer during the stretching process between WS particles and PURb.

    “indicating an improved interfacial adhesion and improved stress transfer during the stretching process between WS particles and PURb.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    A further increase in PURb/WS ratio leads to a more effective blowing efficiency due to an increase in the PURb amount, which produces a higher reaction ability and CO2 emission as the -OH groups from polyol and -NCO groups from isocyanate react with each other.

    “a further increase in PURb/WS ratio leads to a more effective blowing efficiency due to an increase in the PURb amount, which produces a higher reaction ability and CO2 emission as the –OH groups from polyol and –NCO groups from isocyanate react with each other”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Chemical treatment changes the ratio between open and closed pores, thus improving the sound resistance ability of flexible polyurethane foams.

    “They found out that chemical treatment changes the ratio between open and closed pores, thus improving the sound resistance ability of the obtained products.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [8] Choe, 2018, Chemical treatment of wood fibers to enhance the sound absorption coefficient of flexible polyurethane composite foams, Compos. Sci. Technol. source

  • May combine two claims.

    Interpretationreasoning

    In the case of 0.40 PURb/WS, the excessive amount of WS particles, or the insufficient amount of PURb, disrupts the foaming process and results in the formation of a more defective microstructure, which determines a higher average value of thermal conductivity, which is 0.0523 W/m·K.

    “In the case of 0.40 PURb/WS, the excessive amount of WS particles, or the insufficient amount of PURb, disrupts the foaming process and results in the formation of a more defective microstructure, which determines a higher average value of thermal conductivity, which is 0.0523 W/m·K.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    For pineapple leaves-based cellulose fibres, chemical treatment did not enhance mechanical performance and reduced the cross-link ability between the filler and polymer matrix.

    “It was observed that the chemical treatment did not enhance the mechanical performance and on the contrary, it reduced the cross-link ability between the filler and polymer matrix.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Jabber, L.J.Y., Grumo, J.C., Alguno, A.C., Lubguban, A.A., and Capangpangan, R.Y. (2020). Influence of cellulose fibers extracted from pineapple (Ananas comosus) leaf to the mechanical properties of rigid polyurethane foam. Mater. Today Proceed., in press. source

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

    Premisecitation

    Wood chips produced brighter foams with a better photodegradation effect compared to darker ones.

    “wood chips produced brighter foams with a better photodegradation effect compared to darker ones [14]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [14] Delucis, 2019, Surface response and photodegradation performance of bio-based polyurethane-forest derivatives foam composites, Polym. Test. source

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

    Premisecitation

    The addition of hemp fibres improved the tensile and flexural behaviour of PUR biocomposite foams.

    “Authors in References [12,13] demonstrated that the addition of hemp fibres improved the tensile and flexural behaviour of PUR biocomposite foams.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [12] Sair, 2018, Mechanical and thermal conductivity properties of hemp fiber reinforced polyurethane composites, Case Stud. Constr. Mater. source
    • cites [13] Haghighatnia, 2017, Hemp fiber reinforced thermoplastic polyurethane composite: An investigation in mechanical properties, Ind. Crop. Prod. source

  • May combine two claims.

    Premisecitation

    The addition of filler may change the nucleation mode from homogeneous to heterogeneous, and reduce the nucleation energy, thus promoting the formation of a higher number of smaller cells.

    “the addition of filler may change the nucleation mode from homogeneous to heterogeneous, and reduce the nucleation energy, thus promoting the formation of a higher number of smaller cells [51,52]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [51] Sienkiewicz, 2019, Curcumin as a natural compound in the synthesis of rigid polyurethane foams with enhanced mechanical, antibacterial and anti-ageing properties, Polym. Test. source
    • cites [52] Silva, 2020, Evaluation of rubber powder waste as reinforcement of the polyurethane derived from castor oil, Waste Manag. source

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

    Premisecitation

    Contaminants in wood waste are a real issue in waste management which can impact health, the environment, and further reuse in specific applications.

    “Such contaminants are a real issue in waste management which can impact not only on health and the environment, but also on their further reuse in specific applications [6].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Xing, 2020, Microbial remediation for the removal of inorganic contaminants from treated wood: Recent trends and challenges, Chemosphere source

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

    Interpretationnone given

    All the reviewed studies show that WW-based fillers or aggregates have a great potential to be used in PUR biocomposite foams.

    “All these studies show that WW-based fillers or aggregates have a great potential to be used in PUR biocomposite foams.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    A lower ratio of PURb/WS indicates a lower amount of PURb, which hinders the foaming process of PUR biocomposite foams.

    “a lower ratio of PURb/WS indicates a lower amount of PURb, which hinders the foaming process of PUR biocomposite foams”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductreasoning

    The same raw materials and conditions were adopted in the tests, and therefore the impact of moisture content and phase composition is not prominent.

    “However, the same raw materials and conditions were adopted in the tests, and therefore, the impact of moisture content and phase composition is not prominent.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Silanisation of walnut shells produced PUR biocomposite foams with improved physical and mechanical properties such as compressive and flexural strength, as well as thermal conductivity.

    “The authors of Reference [10] showed that the silanisation of walnut shells produced PUR biocomposite foams with improved physical and mechanical properties such as compressive and flexural strength, as well as thermal conductivity.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] 2020, Effect of wallnut shells and silanized wallnut shells on the mechanical and thermal properties of rigid polyurethane foams, Polym. Test. source

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

    Premisenone given

    The decrease in environmental temperature may impact changes in linear dimensions.

    “Moreover, the decrease in environmental temperature may impact the changes in linear dimensions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    According to dimensional stability results, 0.70 PURb/WS ratio-based PUR biocomposite foams are highly stable in various environmental conditions and conform to DS (70, 90) level 4 for 70 °C/90% environmental conditions, and DS (−20) level 2 for −20 °C environmental conditions.

    “According to dimensional stability (DS) results, 0.70 PURb/WS ratio-based PUR biocomposite foams are highly stable in various environmental conditions and conform to DS (70, 90) level 4 for 70 °C/90% environmental conditions, and DS (−20) level 2 for −20 °C environmental conditions.”
    Quote in the paperSubstantial claim

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

    Premisenone given

    The size of fillers/aggregates and the production technology with its parameters are of great importance as well.

    “Additionally, the size of fillers/aggregates and the production technology with its parameters are of great importance as well.”
    Quote in the paperNot a substantial claim

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

    Interpretationreasoning

    It is hard to compare the obtained numerical values in Table 8 with the percentage values obtained in the current study.

    “Therefore, it is hard to compare the obtained numerical values in Table 8 with the percentage values obtained in a current study.”
    Quote in the paperNot a substantial claim

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

    Premisenone given

    The performance of biocomposite foams independently on the foamed matrix used is determined by the interface between fibre/aggregate and polymer binder.

    “The performance of biocomposite foams independently on the foamed matrix used is determined by the interface between fibre/aggregate and polymer binder.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Pure synthetic matrices are inert to water absorption, which is the main reason for their long period of degradation, while WW-based products are more attractive to microorganisms due to their capability to absorb water.

    “Pure synthetic matrices are inert to water absorption, which is the main reason for their long period of degradation, while WW-based products are more attractive to microorganisms which is due to their capability to absorb water [58].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [58] Czaja, 2017, Evaluation of wood-polyethylene composites biodegrability caused by filamentous fungi, Int. Biodeter. Biodegrad. source

  • May combine two claims.

    Interpretationcitation

    According to the factory-made polyurethane foam harmonised product standard, the obtained biocomposite foams with 0.55-0.85 PURb/WS ratios fall into the fourth stability level and are characterised as extremely stable foams.

    “According to the factory-made polyurethane foam harmonised product standard [61], the obtained biocomposite foams with 0.55–0.85 PURb/WS ratios fall into the fourth stability level and are characterised as extremely stable foams.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [61] EN 13165 (2016). Thermal Insulation Products for Buildings–Factory Made Rigid Polyurethane Foam (PU) products–Specification, European Standardization Committee.

      Not checked in the free run.

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

    Premisecitation

    Similar water absorption phenomena were reported for pre-hydrolysed banana fibre-based polyurethane foam composites and porous polyurethane filled with cellulose fibres from water hyacinth.

    “This phenomenon has also been reported by other authors [59,60] who tested 24 h water immersion of pre-hydrolysed banana fibres-based polyurethane foam composites, and the contact angle of porous polyurethane filled with cellulose fibres from water hyacinth, respectively.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [59] Mohamed, 2010, Study mechanical, swelling and dielectric properties of prehydrolysed banana fiber–Waste polyurethane foam composites, Carbohydr. Polym. source
    • cites [60] Sittinun, 2020, Improving the oil sorption capability of porous polyurethane composites by the incorporation of cellulose fibers extracted from water hyacinth, Compos. Commun. source

  • May combine two claims.

    Interpretationown data

    PUR biocomposite foams tested at −20 °C can be described as extremely stable and fall into the highest level indicated by the product standard.

    “Additionally, according to the results presented in Table 7, PUR biocomposite foams when tested at −20 °C can be described as extremely stable and fall into the highest level indicated by the product standard.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [61] EN 13165 (2016). Thermal Insulation Products for Buildings–Factory Made Rigid Polyurethane Foam (PU) products–Specification, European Standardization Committee.

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    At 0.70 PURb/WS, WS particles are sufficiently covered with the PU matrix, leading to better interfacial interaction and greater tensile strength values.

    “In this case, WS particles are sufficiently covered with the PU matrix, thus leading to a better interfacial interaction and greater tensile strength values.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    The slight dimensional changes might be attributed to WS particles in such PUR biocomposite foams being more exposed to a humid environment, which has a slightly negative effect on the final product.

    “These slight changes might be attributed to the fact that WS particles in such PUR biocomposite foams are more exposed to a humid environment, which has a slightly negative effect on the final product.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    A 0.40 PURb/WS ratio was considered insufficient for even wetting of the WS filler, creating a path which can be easily accessed by water molecules penetrating through the specimens.

    “As a 0.40 PURb/WS ratio was considered insufficient for even wetting of the WS filler, it creates a path which can be easily accessed by water molecules penetrating through the specimens.”
    Quote in the paperSubstantial claim

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

    Premisereasoning

    The diffusion of gases accelerates with an increase in temperature.

    “It known that the diffusion of gases accelerates with an increase in temperature.”
    Quote in the paperNot a substantial claim

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

    Premisereasoning

    Higher values of compressive and tensile strengths are mostly obtained for PUR biocomposites used for structural, decorative, furniture, etc., applications, while lower strength results are attributed to thermal insulation and sound-absorbing foams.

    “Higher values of compressive and tensile strengths are mostly obtained for PUR biocomposites used, e.g., for structural, decorative, furniture, etc., applications, while lower strength results are attributed to thermal insulation and sound-absorbing foams.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The most efficient ratio is 0.70 PURb/WS, which gave stable products with the best properties for loose-fill building insulations.

    “It was found that the most efficient ratio is 0.70 PURb/WS, which gave stable products with the best properties for loose-fill building insulations”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The loose and pulled-out WS particles at 0.40 PURb/WS indicate poor interfacial adhesion and insufficient wetting between the WS surface and the PU matrix, which leads to voids and formation of open pores in the foam structure.

    “This indicates poor interfacial adhesion and insufficient wetting between the WS surface and the PU matrix at a 0.40 PURb/WS ratio, which in turn leads to voids and the formation of open pores in the foam structure (Table 4).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    WS filler is sufficiently water vapour permeable, therefore the obtained PUR biocomposite foams are characterised by a lower water vapour resistance and water vapour diffusion resistance factor compared to commercial ones.

    “It is obvious from Figure 4 that WS filler is sufficiently water vapour permeable, therefore, the obtained PUR biocomposite foams are characterised by a lower water vapour resistance and water vapour diffusion resistance factor compared to commercial ones.”
    Quote in the paperSubstantial claim

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

    Premisenone given

    There is a lack of information about short-term absorption by partial immersion of various polymers-based biocomposite foams.

    “However, there is a lack of information about short-term absorption by partial immersion of various polymers-based biocomposite foams.”
    Quote in the paperNot a substantial claim
50 of 50

  • The paper relies on this without support.

    The quality of wood waste is the main aspect influencing the stability of the final products.

    “It is known that the quality of WW is the main aspect which influences the stability of the final products.”

  • The paper relies on this without support.

    Wood waste-based fillers contain free hydroxyl groups that can link to isocyanate groups, conferring sufficient compatibility with polyurethane.

    “the presence of free hydroxyl (–OH) groups susceptible to link to isocyanate (–NCO) groups, which confers a sufficient compatibility with the polyurethane (PUR)”
2 of 2

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?

  • Different composite materials and thermal and noise insulating products are made using CDWW.

    “Moreover, different composite materials and thermal and noise insulating products are made using CDWW [49,64,65,67].”

    From Circular Economy of Construction and Demolition Wood Waste—A Theoretical Framework Approach (2022) · cites this paper as [67]

    Section 3.6 discusses wood-waste-based biocomposite foams for thermal insulation and sound absorption. But Section 2.1 identifies this study’s wood fillers as sawdust and bark from a forest region, not construction-and-demolition wood waste (CDWW). The paper therefore supports the product types, but not the claim that they are made using CDWW. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Abstract reverses the compressive-strength trend

    Minor

    The abstract says compressive strength increased from 142 to 272 kPa as the PURb/WS ratio rose to 0.70. The results instead say compressive strength decreases as the ratio increases, and the conclusion reports 220 kPa-not 272 kPa-at 0.70.

  • Water-absorption results refer to an untested 0.75 ratio

    Minor

    The water-absorption discussion assigns a result to 0.75 PURb/WS, but the four ratios identified for the prepared foams include 0.70, not 0.75.

  • Two different reductions are given for WS versus uWS thermal conductivity

    Minor

    The results give both 3.0% and 2.2% for the difference in thermal conductivity between WS and uWS.

3 of 3

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.1016/j.mtcomm.2020.101110

    Major

    The cited work was retracted on 2020-04-24 (notice 10.1016/j.mtcomm.2020.101110), before this paper was published (2020-11-25). Its authors could have known.

    Cited work 10.1016/j.mtcomm.2020.101110 · retracted 2020-04-24 · notice 10.1016/j.mtcomm.2020.101110 · this paper published 2020-11-25

1 of 1

Cites

1 retracted

Flagged first, then by citations

Cited by

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Related

Authors
Augaitis, N., Vaitkus, S., Członka, S., & Kairytė, A.
Affiliations
  • Vilnius Gediminas Technical University (LT)
  • Lodz University of Technology (PL)
Corresponding author
Vaitkus, Saulius
ORCID
Venue
Materials
Publisher
MDPI AG
Published
2020-11-25
Volume
13
Issue
23
Pages
5336
ISSN
1996-1944 (ISSN-L)
DOI
10.3390/ma13235336
PMC
PMC7728156
OpenAlex
W3108940594
Semantic Scholar
5772e63fae6317da6fab8d7ed93197bfa46c0666
Cited by
34
References
57
Citations by year
2026: 3 · 2025: 8 · 2024: 5 · 2023: 5 · 2022: 10 · 2021: 3
FWCI
2.34
Type
journal article
Language
en
Open access
Licence
Locations
  • Materials (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Topics
  • Physical Sciences › Engineering › Building and Construction › Hygrothermal properties of building materials
  • Physical Sciences › Materials Science › Polymers and Plastics › Polymer Foaming and Composites
  • Physical Sciences › Engineering › Building and Construction › Building energy efficiency and sustainability
Keywords
wood waste, loose-fill insulation, building insulation, waste recycling, thermal conductivity, water absorption, water vapor resistance, compressive strength, tensile strength, filler incorporation

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 2026-10-21.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-21.

Cited sources are checked by gpt-6-sol.

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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