Papers by Keyword: Silk-Based Composites

Abstract: There has been a concern over many years on the usage of existing metallic and ceramicbased biomaterials for implant design and development due to the necessity of conducting operations for patients to remove and maintain implants after they complete their desired functions. Recently, the development of biodegradable polymers like poly(glycolic acid), poly(lactic acid), and their co-polymers etc. have emerged and provided an entirely new concept to tackle this problem as these polymers can be fully or partly degraded or resorbed by the human body, i.e. an extra operation for removing the implants can be avoided, which can highly alleviate the hard feeling of the patients that come from psychological and physiological pressures. Natural fibres have been well recognized as potential micro-reinforcements for the enhancement of mechanical, thermal and structural properties of biodegradable polymer composites, without generating any harmful by-products and adverse effects during their degrading process to the patients. These natural fibers can be mainly classified depending on their origin into two categories; they are (i) plant-based and (ii) animal-based natural fibers, like spider and silkworm silks. Since the last decade, silkworm silks have been used as reinforcements for fabricating biocomposites. However, no comprehensive study, particularly on the correlation between the mechanical properties of the composites, and fiber orientations and configurations has been done to date. In this paper, an in depth study on the mechanical properties of silk/epoxy composites with different fiber contents and orientations, through experimental approach and fractographic examinations will be conducted. Tensile property tests for all silk/epoxy composite samples will be performed. Failure samples will be examined by using scanning electron microscope (SEM) to investigate the failure mechanism of the composites.

Abstract: 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 microreinforcements 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.