Mechanical performance of silk-based structural composites

With the strong emphasis on environmental awareness, it has brought much attention in the development of recyclable and environmentally sustainable composite materials since the last decade. Environmental legislation as well as consumer demand in many countries is increasing the pressure on manufacturers of materials and end-products to consider the environmental impact of their products at all stages of their life cycle, including recycling and ultimate disposal. Silk fibers, spun out from silkworm cocoons, consist of a fibroin core surrounded by a protein layer called "sericin", and these fibers are biodegradable and highly crystalline. It has been known that these fibers have higher tensile strength and are more predictable in failure than glass and synthetic organic fibers. Recently, few preliminary studies have reported that the use of these silks, as micro-reinforcements to replace un-recyclable carbon and glass fibers for polymeric-based structural composite materials can enhance their mechanical and thermal properties, with reducing the amount of un-decomposable wastes and pollutants. In this paper, the mechanical properties of silk-based epoxy composites formed by different controlled manufacturing parameters are elaborately studied.