1. Animal fiber
In order to survive and develop, natural organisms have created a series of optimal compositions and structures under the promotion of the external environment, so that organisms have special structures and functions to adapt to natural environmental changes. For example, the diameter of the silk that spiders spit out in normal environments is 0.5-1.0μm, has good toughness (elongation at break of 14%), and has strong ability to withstand heavy objects or strong external impacts. It can be used to prepare bulletproof vests and body armor worn by soldiers. The protective cover of military machinery can also be used in aerospace, construction, medicine, health care and other fields, and has huge potential application value. Silk is another important natural protein fiber. It is composed of silk fibroin and sericin wrapped around the silk fibroin. Each silk is composed of two single fibers side by side. The linear density of the fiber after degumming is 1.1~1.3 dtex. The strength of silk is high, the elongation at break can reach 15%~25%, and the abrasion resistance is better than other natural fibers. It also has important applications in medicine, textile and military fields. In addition, animal fur (the microfibril diameter of wool fibers is 10-15nm) and the fibril linear density in the cortex are both less than 1.1dtex, which is the main reason for the excellent performance of natural leather, and has become the first choice for bionic research and artificial leather manufacturing.
2. plant fibres
In addition to animal fiber, plant fiber is another natural fiber with excellent performance. It is mainly distributed in the thick-walled tissue of seed plants. The basic component is cellulose, a polymer composed of 7,000 to 10,000 glucose molecules connected by glycoside chains. As an outstanding representative of ultra-fine natural plant fibers, the diameter of cotton fiber is 10-17μm, which constitutes the smallest unit of cotton fiber-the diameter of microfibril is about 6nm. It is widely distributed on the surface of plant seeds, which is the theoretical research and industrialization of the textile industry. Important raw material for application. In addition, in plant stems, some hemp herb stems. For example, ramie, jute, flax, etc., have relatively developed fiber bundles with fiber diameters between 10 and 40 μm, which are important sources of raw materials for industrial textiles.
