关键词: 青藏高原, 防护用纺织品, 力学性能, 热稳定性, 老化过程

Abstract: Protective textiles are an important part of industrial textiles. In recent years, a lot of natural disasters show the tendency of strong explosion and large spread, which increases the safety risk of operators in special environment. To protect the safety of operators, the higher requirements are proposed for protection technology. Protective textiles are inevitably aged during repeated use and become unusable because of performance degradation. At present, the research of aging of the protective textiles mainly focuses on the single atmospheric environment, and the special atmospheric environment of the Qinghai-Tibet Plateau with strong solar radiation and large temperature difference between day and night is less studied. Therefore, it is necessary to study the coupling damage mechanism of UV irradiation and temperature on protective textiles.
According to the monthly average temperature and ultraviolet radiation of three typical cities in the Qinghai-Tibet Plateau (Xining, Golmud and Rikaze) in one year, three groups of control experiments were designed. The microscopic morphology, mechanical properties, thermal properties and chemical structure of the camouflage fabric before and after indoor accelerated aging were analyzed in order to research the indoor accelerated aging process of fabrics.
The results show that the fabric structure is complete and the surface is smooth before aging. After aging, the fiber surface becomes rough and uneven, and the color becomes poor. Cracks appear in some areas and gradually expand during aging. The scale structure on the surface of the wool fibers is destroyed, and the inner cortical layer structure is exposed. The most serious is that the fiber is fractured, the fiber shape is deformed and the fiber structure is no longer complete. With the increase of aging time in three indoor accelerated environments, the breaking strength, tearing strength and bursting strength of camouflage fabrics are all decreased. After 7 h of acceleration in the third indoor environment, the warp and weft breaking strength of the fabric are decreased by 24.16% and 26.87%, respectively. The bursting strength is decreased by 21.51%. The warp tearing strength and weft tearing strength are decreased by 40.43% and 50.50%, respectively. The tear strength is more susceptible to environmental aging. Both the maximum thermal decomposition temperature and melting temperature of the aged fabric are moved to the low temperature zone. The decrease of the maximum thermal decomposition temperature indicates that the thermal stability of the fabric becomes worse and decomposition is easier to occur. The decrease of the melting temperature indicates that the irregular molecular chains in the amorphous region of fiber molecules move more violently, which leads to the decrease of crystallinity because the crystals inside the fiber is melted. The two reasons mentioned above lead to the decline of fabric mechanical properties. The absorption peak position and peak shape of the fabric are basically unchanged and no new chemical bonds are formed after aging, which indicates that no new substances are produced in the aging process. Only the strength of partial absorption peaks has some changes, which can be explained that the relatively stable oxidation products are generated during the oxidation of the fabrics aging process.
The research of this aging process and fabric properties changed can provide theoretical support for the development of protective textiles in the Qinghai-Tibet Plateau.

Key words: Qinghai-Tibet Plateau, protective textile, mechanical property, thermal stability, aging process