A sustainable bioplastic obtained from rice straw

Abstract

Abstract A new bioplastic was produced from rice straw, an agricultural waste that generally is not recovered. For the synthesis the sample was treated by using the Naviglio extractor, then it was dissolved by trifluoroacetic acid. The material exhibits good mechanical properties, with tensile strength and elongation at break equal to 45 MPa and 6.1% and 10 MPa and 63% for dried and wet dumbbells, respectively. It results that the mechanical properties of the produced bioplastic, in its dry state, are comparable to those of polystyrene, while cast bioplastic in wet state is similar to plasticized poly(vinyl chloride). This demonstrates the high mechanical performance of the newly obtained bioplastic both in dry and wet status. The morphology of bio-based material, investigated by scanning electron microscopy, showed a uniform and compact surface structure. 2D X-ray Diffraction analysis reveals that bioplastic is essentially amorphous. Mass loss test noted that it is completely decomposed after being embedded in soil for 105 days. Industrial and environmental advantages of the newly obtained biomaterial are evaluated in terms of embodied energy and CO2 footprint production and in comparison with thermoplastic starch and other plastics. Finally, shape memory test revealed promising dual shape effects of the biomaterial, with a partial but significant shape recovery. In summary, depending on the environmental humidity, the material shows a dual mechanical behaviour that can be exploited to obtain shrink films and sheet or to drive shape memory effect. Therefore, we suggest rice straw bioplastic as a new potential eco-material for different application fields.