Production, application and modification of the ho

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Research on production, application and modification of polyphenylene sulfide

1. Overview

polyphenylene sulfide is abbreviated as PPS. As a special engineering plastic with excellent performance, polyphenylene sulfide has excellent high temperature stability, flame retardancy, chemical corrosion resistance, good mechanical and electrical properties, and has high crystallinity. PPS model products also have good dimensional stability at high temperature, and can be processed by a variety of processing and molding methods, And it can be precision formed. It is widely used in automotive, electrical, electronic and mechanical fields. In recent years, new products and new uses of PPS are still developing and producing continuously. Due to its excellent performance and wide application, PPS has become the largest variety of special engineering plastics and ranks sixth in the output of general engineering plastics

2. Production status

the literature reports that there are four main synthetic routes for PPS, but the most widely used technology for industrial synthesis is the polycondensation of dichlorobenzene and sodium sulfide in polar solvents N-methyl pyrrolidone or hexamethylphosphoryl triamine. PPS was first industrialized by Phillips oil company of the United States in 1973, and was put on the market under the trade name "Ryton", which was favored by the majority of users. After the patent protection expired, many companies in Germany and Japan built PPS devices one after another. At present, the main PPS manufacturers in the world include Phillips oil company and FORTRON company of the United States. Germany and China will show a stable and progressive situation in the export growth of extruder products. Ear company, Toray Philips company of Japan, Wuyu chemical industry company, Tojo Baoshi Valley company, Greater Japan ink chemical company, Toho petrochemical industry company, etc., with a total annual production capacity of about 60000 T/A

as early as the 1970s, China's Shanghai, Tianjin, Guangzhou, Sichuan and other places carried out research and development work on the production and application of PPS. It is reported that there are many small-scale production devices in China, such as Sichuan special engineering plastic factory, Sichuan Guanghan high tech material development Co., Ltd., Gansu chemical machinery factory, Beijing Institute of chemical industry, Sichuan Neijiang polymer material factory, Zigong chemical reagent factory, Guangzhou Chemical Reagent Factory, etc Due to many factors such as cost, the units are seriously under started, and many units are closed soon after starting. Among them, the earliest and most powerful research unit is the Institute of materials of Sichuan University, which has obtained a number of national patents. The Institute has undertaken the national "863" plan of PPS synthesis research project. In 2002, domestic polyphenylene sulfide synthesis technology made a breakthrough. Sichuan Huatuo Industry Development Co., Ltd., which is controlled by Sichuan University, built a 50 ton/year pressure synthesis injection molding grade polyphenylene sulfide resin device, After examination and identification, all indicators of the product have reached the advanced level abroad. In 2003, the company started a 1000 t/a polyphenylene sulfide plant in the China patent technology industrialization demonstration park in Deyang City, Sichuan Province, marking the considerable progress of China's polyphenylene sulfide industry. At present, the production capacity of polyphenylene sulfide in China is about 2500t/a, and the annual output is about 500t/A. Although China has made breakthroughs in the synthesis of polyphenylene sulfide, there are still some aspects that need to be improved, such as raw material refining, polymerization process, solvent recovery, product post-treatment, equipment structure, product development and engineering amplification

3. application and market

pps has a good market prospect and wide application, which comes from its excellent internal quality and superior performance. PPS has excellent thermal stability, short-term heat resistance and long-term continuous use of thermal stability are better than all current engineering plastics. Chemical corrosion resistance, PPS resin chemical corrosion resistance and so-called "king of plastics" PTFE, below 200 ℃, almost no solvent can dissolve it. Physical and mechanical properties: PPS resin has very low melt viscosity, good fluidity, and is very easy to wet and contact with glass fiber. Therefore, the filler is easy. The glass fiber or glass fiber inorganic filler reinforced injection grade pellets prepared with PPS resin have extremely high tensile resistance, impact resistance, bending resistance and ductility. Dimensional stability: PPS injection molded products have good creep resistance, low coefficient of linear expansion and good dimensional stability. Bonding performance: PPS has very high bonding strength to glass, aluminum, stainless steel, etc., and the bonding strength to glass is even greater than the cohesion of glass. Due to its good corrosion resistance and bonding performance, PPS is extremely suitable for lining chemical equipment. In addition, the chemical structure of PPS makes it difficult to burn without adding flame retardants. PPS has very low dielectric constant, inductive stress rate and dielectric loss factors, and has excellent insulation and dielectric properties in high temperature, high humidity and other environments. Because fitlin said that PPS has unparalleled comprehensive performance, it has been applied as a non-metallic structural material with high temperature resistance and high performance in aerospace, nuclear industry, electronic and electrical and other high-tech fields. Moreover, it also has broad prospects in the field of civil industry. For example, PPS can be made into various high-temperature and corrosion-resistant dilute sulfuric acid hydrolysis tanks, exhaust valves and discharge valves; Reinforced PPS products are used for electrical parts, such as transformer framework, coil framework, pipe sockets, connectors and inserts with metal working under heating conditions; Pump casings, impellers, fans, blades and filters in the machinery industry; Engine piston rings, exhaust circulation valves, automobile flow valves, etc. in the automotive industry; In addition, it also has good application prospects in the field of household appliances and office automation. Especially with the trend of lightweight and low cost of automobiles, PPS with good mechanical properties, high dimensional accuracy, high temperature resistance and corrosion resistance has great application potential in the automotive industry

pps/pbt (polybutylene terephthalate)

due to the high elongation and poor impact resistance of PPS, the blending of PBT resin and PPS can not only maintain the original excellent properties of PPS, but also achieve the purpose of toughening. At present, the alloy has been studied effectively in China

pps/ptfe (polytetrafluoroethylene)

at present, the research and development of pps/ptfe alloy has received special attention. This kind of high wear-resistant lubricating materials are widely used in machinery, automobile, aerospace and military fields. Both PPS and PTFE resins are 6 The distance between the dental electromagnetic clutch yoke and the armature is not suitable for excellent high temperature resistant, corrosion-resistant and high insulation engineering plastics. In contrast, PPS resin has better formability, while PTFE has better toughness and lower friction coefficient. This kind of alloy based on PP safety technical specification for portal steel pipe scaffold in building construction JGJ 128 ⑵ 000s has higher toughness, corrosion resistance and self lubrication than pure PPS; This kind of alloy, mainly PTFE, can improve the formability, dimensional stability, creep resistance, compressive strength and reduce air permeability of PTFE, and can be used to manufacture gears, bearings and gasket materials. However, the compatibility between PPS and PTFE is very poor, and it is difficult for general compatibilizers to obtain good results, so special compatibilizers need to be developed. It is reported that tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (PFA), tetrafluoroethylene hexafluoropropylene copolymer resin (FEP) and tetrafluoroethylene propylene ether resin (EPE) developed by Daikin company in Japan can be used as compatibilizers between PTFE and PPS. In the blending modification process of PPS and PTFE, pea, FEP EPE can reduce the interfacial tension between the two phases, and the modified PPS material shows excellent friction resistance. Pps/ptfe is the most widely studied and used PPS alloy at present, and there are many new varieties, such as glass fiber reinforced pps/ptfe alloy, which is mainly used to manufacture automobile dampers; Pps/ptfe filled with alumina, as a high-performance anti-wear and anti-wear material; Carbon fiber reinforced pps/ptfe, used to manufacture high-performance sliding parts; Pps/ptfe reinforced and filled with carbon fiber and molybdenum dioxide is mainly used as a coating with high adhesion, high thermal stability and wear resistance

at present, PES (polyether sulfone), PC (polycarbonate), PEK-C (phenolphthalein polyether ketone), ppsk (polyphenylene sulfide ketone), PPO (polyphenylene oxide), PE (polyethylene), ABS and acrylic rubber elastomers are also studied and developed for blending modification with PPS. For example, pps/pc alloy can improve the impact strength of PPS and the flame retardant performance of PC, which is mainly used in machinery industry, electronic and electrical industry and automotive industry; Pps/ppo alloy has been used as battery box and battery cover; Pps/pe has been used in wire and cable and other communication and information industries

5. Conclusion

due to the good development potential and market prospect of PPS, and the use of PPS involves the military industry, foreign countries have not exported all resin products to China. The state attaches special importance to PPS research. After years of efforts and the efforts of many scientific research institutions, a breakthrough has been made in recent years, and a 1000 t/A-class device with independent intellectual property rights has been built. With the breakthrough of PPS technology in China, Moreover, domestic PPS synthetic raw material p-dichlorobenzene is of high quality, low price and sufficient supply, which indicates that China's PPS industry will usher in a rapid development stage. In view of the current situation of PPS production and application in China, the following development suggestions are put forward for China's PPS industry

although China has made some breakthroughs in PPS synthesis technology, there is still a big gap compared with foreign countries in terms of variety, quality and device scale. In the future, we should speed up the improvement and improvement of synthesis technology and develop high-performance PPS products, such as developing linear PPS to replace the current cross-linked PPS, and accelerating the research and development of PPS with impact resistance, high strength, high fluidity and blow molding grade; In addition, accelerate the development of new manufacturing processes to synthesize aromatic amorphous PPS, introduce sulfone based structure into the structure, and prepare amorphous polymer polyphenylene sulfide sulfone (PPSS) and crystalline PPS copolymers, closely following the development trend of international PPS synthesis and application

with the breakthrough of large-scale synthesis technology of PPS in China, in the future, China should speed up the research and development of filled, reinforced and co mixed gold, especially the development and application of PPS filled with glass fiber and carbon fiber, pps/ptfe, pps/pe,/pps/pa, pps/peek and other alloys, so as to meet the needs of all industries in China, especially the aerospace and automotive industries for PPS; On the other hand, expand the application field of PPS, increase the consumption of PPS, and promote and drive the healthy and orderly development of China's PPS industry. (end)

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