This project belongs to the field of textile science and technology. Par-aramid fiber is one of the three major high-performance fibers and an indispensable and important strategic material. Our country has carried out research for more than 40 years. It has not been localized so far and still relies on imports, which seriously threatens my country's military security.
The project carries out systematic research on key scientific and technical issues in the preparation of high-modulus aramid fibers, and establishes an annual output of 1000 tons of ultra-high molecular weight PPTA resin, an annual output of 1000 tons of high-modulus aramid fibers, and an annual output of 50,000 pieces of aramid fibers reinforced high-voltage power grids flexible spacer production line, and realize the localization of equipment and raw materials.
High molecular weight PPTA resin is the "bottleneck" for the localization of aramid. The project systematically studied key scientific and technical issues in the continuous preparation of PPTA resin, including polymerization-induced phase transformation, polymerization reaction rules and its influencing factors, twin-screw thread structure design and temperature distribution, solvent recovery and purification, etc.; Using domestic monomers as raw materials, a continuous polymerization production line with an annual output of 1000 tons has been established, realizing the localization of ultra-high molecular weight PPTA resin, stable production and quality, and stable concentration log viscosity of 9.2dl/g (the general level at home and abroad is 6.5dl/g).
The viscosity of PPTA crystal spinning fluid is high, making it difficult to dissolve, defoam, filter and spin. The project systematically studied the key scientific and technical issues of high-viscosity liquid crystal fluid spinning and its high modulus, including preparation of high-viscosity uniform spinning solution, liquid crystal fluid filtration and defoaming, liquid crystal spinning and high-modulus condensed state structure control, etc. An annual output of 1000 tons of liquid crystal spinning and high-modulus aramid production line has been established, achieving the localization of high-modulus aramid and stable production and quality. After testing, the product shows that its strength is 21.6 cN/dtex, its modulus is 794cN/dtex, and its performance reaches DuPont's K49 level. The product has been applied by a large number of enterprises and has responded well.
On the basis of the research and development of unit key equipment such as ultra-high molecular weight PPTA preparation, high-viscosity liquid crystal spinning and high-modulus condensed state control, system integration and automated control technology have been carried out to achieve the localization of equipment.
The resonance "dancing" of ultra-high voltage power grids caused by strong winds is a world problem. The project is the first in the world to propose a new method to use flexible spacer rods to prevent wires from resonating and "dancing" in strong winds. According to the requirements of flexible spacer rods, the project developed a special aramid grade, overcome a series of key technologies such as the design, manufacturing and testing of flexible spacer rods, and successfully developed flexible spacer rods. After more than a year of application, the power grid accident rate has been greatly reduced, and product standards have been formulated, and large-scale promotion and application are being carried out (currently there are about 2 million rigid spacer rods in use, with a market of more than 20 billion yuan).
After expert appraisal, the flexible spacer preparation technology is at the international leading level, and the overall aramid preparation is at the international advanced level. Published 8 papers and applied for 20 patents, of which 5 were authorized. High-modulus aramid and flexible spacer rods achieved sales in 2012, with an output value of 130 million yuan, a profit of 28.04 million yuan, and a tax revenue of 20.35 million yuan, with obvious economic benefits. Preparations are under way to build a 20,000-ton aramid and 200,000 spacer rods production line, with an output value of 4 - 5 billion yuan.
The localization of high-modulus aramid fiber provides localized strategic materials for national defense construction, aerospace, economic construction and scientific and technological progress, ending the situation of relying on imports. The project products are undergoing application experiments on aircraft carriers and ships, missiles, aircraft engines, large aircraft, aviation tires, bulletproof armor, personal bulletproof, vehicle lightweight, optical fiber reinforcement, etc.
The localization of ultra-high molecular weight PPTA, high modulus aramid, equipment and raw materials will contribute to the scientific and technological progress of my country's textile industry, the large-scale development of the aramid industry, and participation in the competition of the international high-tech fiber industry.
The new technology of flexible spacer rods for ultra-high voltage power grids will provide a good solution for preventing "galloping" in international ultra-high voltage power grids. It will reduce the huge losses caused by power grid accidents and be of great importance to the construction of ultra-high voltage power grids for coal-electricity conversion and transmission in my country. significance.