Green composites using bioresins from agro-wastes and modified sisal fibers

Green composites were fabricated using modified sisal fibers and agro-waste derived resins from nonedible protein and starch in a simple and cost-effective manner. Sisal fibers were modified using a novel combination of mercerization followed by heat treatment under a pre-determined tension which improved their Young's modulus by over 200% (from 5.5 to 16.7 GPa) and tensile strength by about 50% (from 300 to 450 MPa). The non-edible protein and starch were extracted from defatted karanja (Pongamia pinnata) and mango (Mangifera indica) seed cake wastes, respectively, to prepare the green resins. Composite specimens were fabricated using as-received and modified fibers and agro-waste derived resins using a hand lay-up process followed by hot-pressing. The tensile properties of the composites made with modified fibers showed significant improvement as compared to the composites made with as-received fibers as well as other edible starch or protein-based sisal composites. POLYM. COMPOS., 40:99-108, 2019. (c) 2017 Society of Plastics Engineers