Preliminary Effect of Dual Plasticization and Fiber Size on Cornstalk Fiber-Reinforced PLA/PBS Biocomposites Properties
Abstract
This study investigates the development of sustainable polymer composites using cornstalk (CS) fibers as reinforcement in a polylactic acid/poly(butylene succinate) (PLA/PBS) matrix plasticized with a dual system of polyethylene glycol (PEG) and triacetin (TA). The effects of CS fiber size (≤75 µm and >75 µm) and plasticizer content (5, 7.5, and 10 wt%) on thermal, mechanical, and morphological properties were systematically evaluated. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed no significant differences in thermal behavior across fiber sizes. Dual plasticization effectively increased the melt flow index (MFI) and enhanced processability, but at the expense of overall mechanical properties. Scanning electron microscopy (SEM) confirmed adequate dispersion and interfacial adhesion without chemical bonding, as supported by Fourier-transform infrared spectroscopy (FTIR). The results reveal that all CS-reinforced PLA/PBS composites exhibit low thermal conductivity, comparable to conventional gypsum board, demonstrating the potential for developing agro-waste-based polymer composites suitable for thermal insulation applications in architecture.