Using Silkworm Cocoons as Reinforcements to Fabricate Impact-Resistant Composites: A Comparative Study Between B. mori and A. pernyi Silkworm Cocoons

Silkworm cocoons are distinguished by their lightweight and robust structural properties, effectively safeguarding the pupae from predators and environmental threats. They are promising candidate materials for manufacturing impact-resistant composites. However, their mechanical properties exhibited remarkable variability between wild and domesticated species. In this study, we systematically investigated and compared the mechanical performance of silkworm cocoons from Bombyx mori (B. mori) and Antheraea pernyi (A. pernyi) through a series of tests, including tension, compression, puncture, and dynamic mechanical analysis. Using these silkworm cocoons, we successfully fabricated two kinds of epoxy-based composites and evaluated their mechanical performance through tensile, flexural, and ballistic impact testing. Finally, finite element analysis was also carried out to better understand their failure mechanisms. Results indicated that the addition of silkworm cocoons improves the specific flexural strength and modulus of their reinforced composites in quasi-static tests and also greatly enhances their resistance to high-speed ballistic impact. Especially, the specific energy absorption of ACC70 has surpassed that of natural fiber composites such as flax and hemp, as well as carbon fiber composites and glass fiber composites. These composites absorb the kinetic energy of projectiles through mechanisms such as fiber fracture, matrix cracking, delamination, and “back convex” formation.