Impact of hydration on the mechanical properties and damage mechanisms of natural silk fibre reinforced composites

Silk fibres exhibit good biodegradability, biocompatibility and balanced strength and toughness, which are useful for toughness/impact-critical composites in the biomedical field. However, the impact of hydration has not been studied for silk fibre-reinforced polymers (SFRPs). In this work, SFRPs fabricated vacuum-assisted resin infusion (VARI) were treated under three hydration conditions. A hydration condition of 40 degrees C at 89% relative humidity (RH) was sufficient to induce a reduction in the tensile and flexural modulus and yield strength of SFRPs. Acoustic emission (AE) analysis showed that interface failure played a key role in the damage modes of SFRPs. Although mild hydration treatment appeared not to affect SFRPs, high hydration led to more susceptible interfacial failure. This work is intended to reveal the structural mechanisms of SRPPs under hydration, and to provide a useful reference for potential biomedical applications.