Hybrid effects of Bombyx Mori and Antheraea Pernyi silk fibre on the characteristics of their composites

The biocompatible and biodegradable silks, have become promising fibre reinforcements for composites owning to their high toughness and specific strength. As dozens of silk fibre type exist, comprehensive understanding and comparison of their characteristics are crucial for fibre selection, and the hybrid of different silk fibres may provide better overall characteristics and open up new opportunities for their applications. This paper focused on the properties of Bombyx (BM) and Antheraea Pernyi (AP) silk fibre hybrid composites. Their mechanical and thermal properties, as well as the temperature influence from −50–60 °C were investigated. From experimental results, more BM silk fibres provided higher modulus and strength, while higher AP silk content could improve the impact toughness for silk fibre composites (SFCs) in general. Additionally, all mechanical properties of SFCs showed greater sensitivity to temperature change as the increase of AP silks within the composites on the whole. Damage mechanism studies demonstrated the hierarchical micro-fibre slippage and dissociation of AP silk fibres during their fracture process, which could promote the energy absorption during composite mechanical testing, and these mechanisms were more notable as temperature rose. In summary, the hybrid 8AP+ 4BM SFCs exhibited more favourable performance than both pure AP and BM SFCs, with tensile strength, modulus and impact strength reaching 96 MPa, 5.4 GPa and 64 kJ/m² respectively (at 23 °C), plus the glass transition temperature of 95 °C. It is also expected that greater benefits from fibre hybrid could be achieved with optimised BM/AP ratio and the stacking sequence.