On August 22, 2019, Beijing Time, "Nature Communications" published online the latest research results of the Associate Professor Guan Juan's Research Group of Beijing University of Aeronautics and Astronautics, "Integrating tough Antheraea pernyi silk and strong carbon fibres for i-impact composite materials with wild tussah silk/carbon fibres hybrid structure". Mpact critical structural composites, using wild tussah silk and carbon fiber as tough phase for the first time, constructed a series of epoxy resin matrix composites with high rigidity and strength, realized the perfect combination of two kinds of high performance fibers, and opened up a new direction for the application of natural silk fibers.
The first author is Dr. Yang Kang. The first author is associate professor Guan Juan, School of Materials Science and Engineering, Center for Advanced Structural Materials and Biomaterials Research. The senior author is Robert Ritchie, Academician of the University of California, Berkeley, Professor Shao Zhengzhong, Fudan University, Keiji Numata, Institute of Physical and Chemical Research, Japan. Researchers participate in cooperation. This research is supported by the Excellence 100 Program of Beijing University of Aeronautics and Astronautics and the Young Top Talents Program.
Wild tussah silk, a gift given by nature to Chinese people
Wild tussah silk is mainly produced in Liaoning and Shandong provinces of China. After tens of millions of years of natural selection, its protein sequence structure (oligoalanine fragment), aggregation structure and nano-fiber structure are closer to spider-towed silk than mulberry silk, which can be called "spider silk in silk". In addition, although the tensile strength of tussah silk is only slightly higher than that of mulberry silk (higher than that of ordinary epoxy resin), its tensile fracture energy 150 MJ M-3 is much higher than that of mulberry silk - 70 MJ M-3 , so it is very tough. However, tussah silk is not used to strengthen and toughen composite materials. This paper focuses on improving the toughness and energy absorption properties of composites by tussah silk with excellent mechanical properties, which may provide new ideas for the selection of lightweight, high toughness and impact resistant materials in aviation and automotive fields.
Study on Natural Silk Composites Grounded in Beihang
Professor Fritz Vollrath, an expert on animal silk at Oxford University, predicts that the most likely application areas of silk fiber composites are structural materials with high energy absorption requirements, such as military helmet and wind turbine blades. In 2014, Guanjuan team carried out a systematic research on silk fiber composite materials (SFRP). The results showed that the impact properties of mulberry/tussah fiber composite materials with volume fraction higher than 50% were excellent and had low temperature toughness of -50 C. Flax plant fibers could effectively regulate the mechanical properties of silk composite materials and enhance the silk quality. Rigidity and strength of composites. Coincidentally, Youssef K. Hamidi team of Houston University on the other side of the ocean also carried out research on silk fiber composite materials, and developed a more suitable resin system for silk reinforcement.
Construction of Hybrid Fiber Composites with Strength and Toughness
Compared with most high performance structural materials, the strength and stiffness of silk fiber composites are still insufficient. In this paper, the researchers used carbon fibers and wild tussah silk fibers to mix, carbon fibers to stiffen and tussah silk to toughen, and successfully constructed interlaminar/interlaminar hybrid composites, which not only guaranteed the flexibility of silk fiber composites under bending and impact modes, but also met the requirements of strength and stiffness of engineering structural materials. The effects of classical hybrid methods (such as interlaminar and intralaminar) and hybrid ratio on the mechanical properties of composites were also studied.
Industrialization Oriented-Comprehensive Performance Assessment
In this paper, researchers believe that the research of engineering materials should ultimately be directed to industrial applications, so they have made a comprehensive evaluation of the properties of tussah silk/carbon fiber hybrid composites: tensile, bending, interlaminar shear, impact, dynamic mechanical thermal analysis, water absorption aging behavior, tensile creep, bending creep and so on. The abundant experimental data show that the alternately laminated tussah silk/carbon fiber hybrid composites have the best fiber-matrix interface among all the hybrid materials, with impact strength twice that of carbon fiber composites with the same volume fraction, and exhibit excellent comprehensive mechanical properties. Use prospects.