Thermal and Mechanical Performance of Maleic Anhidride/Benzoyl Peroxide-Modified PLA/PCL Biocomposites

This study investigated PLA/PCL blends modified with maleic anhydride (MA) via radical grafting using benzoyl peroxide (BPO) as an initiator. Different formulations with 5 and 10 wt.% of PLA-g-MA (containing 1, 3, and 5 wt.% MA) were prepared to evaluate their compatibilizing effect. Samples were characterized thermally, mechanically, and morphologically using DSC, TGA, FTIR, goniometry, SEM, and tensile, impact, and hardness tests. The results show that adding PCL significantly improves the ductility of PLA, though it reduces tensile strength and hardness. Grafting with MA partially improves phase compatibility, as seen by increased elongation at break and impact resistance, especially at intermediate MA concentrations (1–3%). However, higher MA contents lead to greater variability in thermal and mechanical results, likely due to heterogeneous phase dispersion. FTIR analysis detected residual BPO in some formulations, though below 0.1 phr. TGA indicated a slight improvement in thermal stability at 5 wt.% MA. Overall, the findings suggest that controlled use of MA as a compatibilizer enhances the balance of mechanical and thermal properties in PLA/PCL systems.