Mold-Infested Damage Mechanisms and Mechanical Response of Jute/Polylactic Acid Composites

This study investigates mold damage behavior and mechanical response of jute/polylactic acid composites through integrated experiments and simulations to address mold-infested degradation of green composites. Composites with a 40% fiber volume fraction were fabricated via thermocompression molding and subjected to a 21-day mold aging at 25 °C and 85% relative humidity, with a mold-free control group established under identical conditions. Mechanical tests, scanning electron microscopy, and a three-dimensional finite element model based on the Hashin criterion were employed for characterization and simulation. Results demonstrate that mold infestation induces 51.86%, 55.35%, and 42.99% reductions in ultimate tensile strength, bending modulus, and shear strength, respectively, after 21 days, degradation magnitudes far exceeding those observed in the control group. This work clarifies a dual synergistic damage mechanism involving enzymatic hydrolysis and hyphal penetration. The established simulation model shows strong agreement with experimental data, with an average relative error below 8%. These findings provide a theoretical foundation for antimold modification of green composites.