Green composites of polylactic acid filled with natural fiber for biodegradation application

Abstract

This research focuses on how to use natural fibers available from agricultural residues to produce biodegradable materials such as mulch films. Green composites were prepared from natural fibers (peanut shell and bagasse fiber) and polylactic acid (PLA) together with plasticizers. The presence of plasticizers improved PLA molecular mobility as seen by the reduction of glass transition, cold crystallization, and melting temperatures. The addition of natural fibers into PLA brought down decomposition temperature when compared to PLA. The morphological study of the composites showed poor interfacial adhesion between natural fibers and PLA matrix. Moreover, the loading of plasticizers improved distribution of natural fibers in PLA matrix. The composites revealed that tensile strength decreased while Young’s modulus increased with increasing natural fibers content. The added plasticizers into the composites showed increase elongation at break and impact strength. Thermo−mechanical properties revealed improvement of PLA performance at high temperature use by the addition of natural fibers together with plasticizers due to cold crystallization at a high temperature, which developed high storage modulus. The composites showed low water vapor permeability which reduced moisture loss by evaporation and increased the efficiency of water use. The enhancements in degradation of the composites were due to the presence of natural fibers. Furthermore, the study of chemical crosslinking PLA in the presence of crosslinking agent showed that the optimum of thermal, thermo–mechanical, and rheological properties were at 5 phr crosslinking agent content.