Due to the increasing requirements for thermal insulation, portability and functionalization of cold-resistant clothing, the requirements for its basic material, thermal fiber, have become higher and higher. The application potential of natural fibers and traditional chemical fibers has almost been developed. Therefore, structural innovation of traditional chemical fibers is required to obtain better thermal insulation performance. In the 1950s, DuPont of the United States developed special-shaped fibers, which greatly improved the gloss and bulk properties of chemical fibers. Among the many shaped fibers, hollow fibers significantly increase the warming performance of chemical fibers because they significantly increase the content of still air inside them. In the 1970s, researchers developed ultra-fine fibers, and biomimetic materials such as artificial leather made from ultra-fine fibers made chemical fibers' thermal insulation performance on par with natural materials. The research on hollow fibers and ultrafine fibers found that the thermal insulation performance of fiber materials is directly proportional to the static air content inside the fiber materials, inversely proportional to the fiber diameter, and inversely proportional to the overall material density. Aerogel fibers have significant characteristics such as extremely high porosity and ultra-low density. In theory, they are the fiber with the best thermal insulation effect. They are expected to replace ultra-fine fibers and even subvert down. direction. However, the high porosity of aerogels also poses great challenges for its preparation.
In view of this, the aerogel team (http://www.aerogel-online.com/index.php) led by researcher Zhang Xuetong of Suzhou Institute of Nanotechnology and Nanobionics, Chinese Academy of Sciences, obtained nanofiber dispersions by dissolving DuPontTM Kevlar fibers , And then wet spinning, special drying and other processes to prepare a Kevlar aerogel fiber with high porosity (98%) and high specific surface area (240 m2 / g), as shown in the figure. The aerogel fiber has excellent mechanical properties, and can be arbitrarily bent, knotted, knitted, and the like. The aerogel fiber also has excellent thermal insulation properties. The thermal conductivity at room temperature is only 0.027 W / m · K. At low temperatures, its thermal insulation performance is 2.8 times that of cotton, and it can be used in extreme environments of -196 ~ 300oC. Play heat insulation performance for a long time. In addition, the aerogel fiber also has excellent chemical stability, and can be subjected to various modifications such as dyeing, hydrophobicization, and electroless plating without damaging the aerogel main body structure. Finally, the aerogel fiber can also be prepared as an air-conditioning fiber by filling a phase-change material, and its enthalpy value can reach 162 J / g, far exceeding the enthalpy value of the existing commercial Outlast air-conditioning fiber.