PPS plastics (polyphenylene sulfide) is a kind of thermoplastic special engineering plastics with excellent comprehensive properties. Its outstanding characteristics are high temperature resistance, corrosion resistance and superior mechanical properties. English Name: polyphenylenesulphide specific gravity: 1.36g/cm3 molding shrinkage: 0.7% molding temperature: 300-330 ℃. It is a kind of thermoplastic special engineering plastics with excellent comprehensive properties. Its outstanding characteristics are high temperature resistance, corrosion resistance and superior mechanical properties. PPS is a sulfur-containing aromatic polymer. The linear PPS is cross-linked at 350 ℃ or above to form thermosetting plastics, and the branched PPS is thermoplastic. PPS was first manufactured by Phillips in 1971. After the patent expired, Japanese enterprises began to develop and produce PPS. Japanese enterprises are typical of Toray company. At present, the output of Japan is larger than that of the United States. Other manufacturers are also concentrated in the United States, Japan and Europe.

The world's top five PPS manufacturers are Phillips, Toray, tecona, Polly and Japanese ink. China's Tianjin Institute of synthetic materials, Guangzhou Chemical Reagent No.2 factory, Sichuan Zigong chemical reagent factory, the Department of chemical engineering of Hebei Institute of technology and Guangzhou Chemical Research Institute have had a few small tests, but they are unable to produce stably and continuously. At present, the domestic sellers of PPS include Shanghai lianmo Chemical Co., Ltd. by 2000, the output of PPS in the world can reach 50000 tons / year. The largest demand for PPS is 33% in Japan, 32% in North America, 19% in Western Europe and 16% in Asia Pacific.

PPS is a white powder with an average molecular weight of 0.4-0.5 thousand and a density of 1.3-1.8 g / cm3. PPS has excellent thermal properties. After adding glass fiber, the thermal performance index is higher. After 5000 hours of thermal aging at 232 ℃, such as glass fiber, carbon fiber, filler, etc., the mechanical properties of the modified PPS can maintain high mechanical properties and dimensional stability under long-term working load and thermal load, so it can be used in high temperature stress environment.

PPS is a kind of excellent electrical insulating material, which is insensitive to the change of frequency, temperature and humidity. Besides being eroded by strong oxidizing acid, such as concentrated sulfuric acid, concentrated nitric acid and aqua regia, PPS is not eroded by the vast majority of acid and alkali salts It is close to the chemical stability of PTFE. It is insoluble in any known organic solvent when the temperature is lower than 175 ℃, and PPS will not crack when contacting with general organic solvent. Chemical resistance: at present, no solvent has been found that can dissolve polyphenylene sulfide below 200 ℃, which is very resistant to inorganic acids, bases and salts. It is not resistant to chlorinated biphenyls and oxidizing acids, oxidants, aqua regia, hydrogen peroxide, sodium hypochlorite, etc.

The radiation resistance of PPS is good, reaching Gy 1 × 108. It is a new material that other engineering plastics can't match. It is the only ideal material for radiation resistance in the fields of electronics, electrical, machinery, instruments, aviation, aerospace, military, especially in the field of atomic bombs and bullets. The chemical structure of PPS itself is quite stable, and it contains sulfur, which is a flame retardant element. Therefore, PPS has excellent flame resistance. Ignite the test piece, adjust the flow rate of oxygen and nitrogen to observe the combustion. The oxygen concentration that just makes the test piece burn continuously is the limit oxygen index. The higher the value is, the better the flame resistance is. The ultimate oxygen index of pure PPS can be as high as 44, so it has excellent flame resistance. PPS containing fillers or fiberglass has higher oxygen limit index and better flame resistance.

Pure PPS can pass UL-94 V0 when the thickness is 0.8mm. Basically, except for a few grades such as super tough series, UL94 flammability of various grades of PPS belongs to V-0 grade, which is the best grade in UL 94 flammability. The super tough PPS series contains some toughening agents, which will sacrifice some fire resistance. PPS grade with pure PPS and without added conductive material has excellent electrical insulation property. The PPS grade with carbon fiber has a very low volume resistance coefficient.

1. Electrical insulation (especially high-frequency insulation) is excellent, white hard and brittle, there is metal noise when falling on the ground, light transmittance is next to organic glass, colorability, water resistance and chemical stability are good. It has excellent flame retardant and is non combustible plastic.

2. General strength, good rigidity, but brittle, easy to produce stress embrittlement; not resistant to benzene, gasoline and other organic solvents; long-term use temperature up to 260 degrees, in 400 degrees air or nitrogen to maintain stability. By adding glass fiber or other reinforced materials, the impact strength can be greatly improved, the heat resistance and other mechanical properties can also be improved, the density can be increased to 1.6-1.9, and the molding shrinkage can be reduced to 0.15-0.25%, which is suitable for making heat-resistant parts, insulating parts, chemical instruments, optical instruments and other parts.

1. Amorphous material, moisture absorption is small, but it should be dried before forming.

2. The fluidity is between ABS and PC, the solidification is fast, the contraction is small, easy to decompose, the injection pressure and injection speed are high. Mold temperature is 100-150 ℃. The taper of main runner should be large and the runner should be short. The application scope can generally be used to manufacture PPS pipes, PPS plates and other materials, which are mostly used in construction and home furnishing.