Mechanical properties and impact performance of silk-epoxy resin composites modulated by flax fibres

Silk fibres possess good biodegradability, excellent biocompatibility and moderate modulus and stiffness, whereas flax fibres are low cost, renewable natural fibres with high specific strength and modulus. Here we introduce economical flax fibres to modulate the stiffness and impact properties of natural B. mori silk reinforced epoxy composites fabricated via vacuum-assisted resin transfer moulding. Intra-and inter-hybridizations of flax and silk fibres are applied to evaluate the effect on composite mechanical properties including tensile and flexural modulus and strength. The interface properties between the fibres and matrix are investigated using dynamic mechanical thermal analysis (DMTA). Most importantly, falling weight impact experiments reveal that silks can effectively prevent crack propagation whereas flax fibres can greatly enhance the impact load. Our study could offer new solutions towards novel biocomposites with tailored modulus, strength and toughness properties based on natural biopolymer fibres.