Production of Natural Straw-Derived Sustainable Polymer Composites for a Circular Agro-Economy

In this study, attempts were made for the first time to explore the unexploited wheat straw particulates (WSP) as a reinforcement filler with concentrations up to 100% in a thermoplastic polypropylene (PP) matrix to produce a new type of wood plastic composites. The WSP-PP composites were developed by melt blending using the injection molding technique and were investigated for their mechanical, structural, and thermal properties. The present study showed low-density composites with densities varying from 0.84–1.04 gm/cc. Compared to virgin polypropylene, WSP-PP composites showed enhanced impact strength, improved flexural strength and moduli, and lower water absorption. With increasing WSP concentration, the mechanical strength increases, and at 20–30% filler concentration, the composite showed a maximum tensile strength of 27.21 ± 0.67 MPa and flexural strength of 44.48 ± 0.48 MPa. The maximum impact strength of WSP-PP composites (2.04 ± 0.11 kJ/m²) was recorded at 40% filler concentration along with lower water absorption (1.67%). The addition of WSP was found to decrease the thermal conductivity of the WSP-PP composites. The findings of this study confirmed the scope of wheat straw as a potential cellulosic reinforcing filler for manufacturing a new class of green composites of high-performance characteristics which could be explored and beneficial for electrical applications, civil infrastructure, automotive parts, etc. Further, the utilization of this inexpensive raw material for the development of composites leads to a reduction in the practice of open straw burning in fields, thereby causing a decrease in CGH emissions. Thus, the realization of this innovative work will contribute to achieving the United Nations’ sustainable development goals with a sustainable approach toward building a circular economy.

Synopsis: This study explores using wheat straw particulates in a polypropylene matrix for composites for lighter and stronger materials, aligning with sustainability goals in engineering.