Influence of spider silk on the mechanical performance and toughening mechanisms of PLA/Starch biocomposites

This study investigated the effect of spider silk reinforcement on the morphological and mechanical properties of PLA/thermoplastic starch (TPS) composites. PLA/TPS composites were prepared at 70:30, with spider silk incorporated at two levels. The composites were characterized using scanning electron microscopy (SEM) and tensile testing according to ASTM D638, with three specimens tested for each formulation. Incorporation of starch reduced the tensile strength of PLA from 59.0 to 29.45 MPa. Spider silk addition improved the mechanical performance, increasing tensile strength to 47.6 to 50.6 MPa, elongation at break to 5.92% and 6.2%, and toughness to 1.43 and 1.56MJ/m3, respectively. SEM observations showed comparatively fewer visible discontinuities in the spider silk-reinforced composites. The results indicate that silk can improve the mechanical performance of PLA/starch composites, particularly ductility and toughness.