Textile science and technology: the technical direction of breaking through polyoxymethylene fiber has been set

The 12th Asian Textile Conference (ATC12) and 2013 China Textile Academic Annual Conference will be held in Shanghai from October 24 to 26. This meeting invited many well-known experts and scholars in the industry to discuss textile theory research, production practice and technology application. It is understood that Professor Wang Hua of Sichuan Institute of Textile Science will give his opinion on "Research and Application of POM" at the forum.
In the next 40 years, at least half of the global machinery will be made of various fiber reinforced composite materials, which belong to the category of industrial textiles. In recent years, China's industrial textile industry has achieved rapid development, and a number of high-performance fibers with independent intellectual property rights have been developed in China. However, the performance of some existing raw materials cannot match that of similar foreign products, and a number of raw material varieties still cannot be industrialized, requiring a large number of imports.
Polyoxymethylene (POM) is a kind of linear polymer without branched chain, with high density and high crystallinity. It has excellent mechanical and electrical properties, good wear resistance, dimensional stability, chemical resistance, especially outstanding fatigue resistance, good self-lubricating performance, strong colourability, and a wide range of application temperatures. It is one of the three general engineering plastics in the world at present, and is widely used in the automotive industry, various mechanical equipment, instruments and construction equipment and other fields. However, the research and development of polyoxymethylene fiber in China started late. Due to the influence of production equipment and special properties of polyoxymethylene, there is no large-scale production in China at present.
The key technical problem affecting the industrialization of polyoxymethylene is that its crystallization speed is too fast. It cannot be completed by ordinary melt spinning methods like polyester and polypropylene fibers. Polyoxymethylene will crystallize immediately after melting, and it is very difficult to stretch in the later stage. How to control the crystallization time of polyoxymethylene is the most important thing to solve the technical breakthrough. "We should make the more the amorphous area, the better, and the less the crystalline area, the better. In the later stage, let the crystalline part further grow and improve during the stretching process, so as to improve the orientation, thus improving the crystallinity and strength." Wang Hua said. How to control the crystallization time? This requires the design of molecules, some treatment of raw materials, and some modified equipment and processes to complete the resin synthesis. "Through a large number of experiments, we can find and solve problems. As long as we persevere, we will be able to do it and surpass them." Professor Wang Hua's words are full of determination and confidence as a researcher.
"The research and development of new materials and new products is not purely for research, but the ultimate goal of research is to realize the industrialization of new products," said Wang Hua. In fact, there is a large demand for polyoxymethylene in the building materials industry in China. As the concrete will produce original defects (small cracks) in the curing process, if these cracks expand, they will have an impact on the compressive strength, tensile strength and other mechanical properties of the concrete. After adding polyoxymethylene, these problems can be solved. Wang Hua once made an experiment. When 0.9 kg of polyoxymethylene was added to 1 cubic meter of concrete, the breaking strength of concrete could be increased by 28%. However, due to the high price of imported polyoxymethylene, polypropylene fiber is currently used most in China, but its compatibility with concrete is poor, and its dispersion is also poor. "We should not only independently develop the polyoxymethylene fiber, but also develop the relatively cheap polyoxymethylene fiber to make it truly industrialized," said Wang Hua.
At present, the price of foreign fiber grade polyformaldehyde resin is about 30000 yuan/ton, while the price of polyformaldehyde fiber jointly developed by Professor Wang Hua and Yunnan Natural Gas Chemical Co., Ltd. can be controlled within 20000 yuan/ton. "In addition to overcoming technical problems, there must be a breakthrough in price to make the products studied have vitality." Wang Hua proudly said, "As long as there are orders, we can produce." Moreover, Wang Hua has developed more brands of polyoxymethylene fiber grade resins than foreign countries, and there are corresponding independent resin brands for different fiber specifications. Now the production scale of polyoxymethylene fibers can reach the kiloton level.