PPS plastics (polyphenylene sulfide)

English Name: Polyphenylenesulphide, specific gravity: 1.36 g/cubic centimeter, forming shrinkage: 0.7%, forming temperature: 300-330 C. It is a special thermoplastic engineering plastics with excellent comprehensive properties. Its outstanding characteristics are high temperature resistance, corrosion resistance and excellent mechanical properties. PPS is a sulfur-containing aromatic polymer. Linear PPS crosslinks above 350 C to form thermosetting plastics. Branched-chain PPS is thermoplastic.

PPS is a white powder with an average molecular weight of 0.4-0.5 million and a density of 1.3-1.8 grams per cubic centimeter. PPS has excellent thermal properties. The thermal performance index of glass fiber reinforced is higher. After thermal aging at 232 degrees Celsius for 5000 hours, such as glass fiber, carbon fiber and filler, the mechanical properties of the modified PPS can be enhanced. The modified PPS can maintain high mechanical properties and dimensional stability under the action of long-term working load and thermal load, so it can be used in high temperature stress environment.

PPS has a very low dielectric constant and dielectric loss. Its surface resistivity and volume resistivity are insensitive to the changes of frequency, temperature and humidity. It is an excellent electrical insulating material. Its arc resistance time is longer and its chemical stability is quite good. Besides being eroded by strong oxidizing acids, such as concentrated sulfuric acid, concentrated nitric acid and aqua regia, it is not eroded by most acid-base salts. It is close to the chemical stability of PTFE. It is insoluble in any known organic solvents at temperatures below 175 degrees Celsius. When PPS is in contact with ordinary organic solvents, plastic parts will not crack.

Chemical resistance: At present, no solvent that can dissolve polyphenylene sulfide below 200 C has been found. It has strong resistance to inorganic acids, alkalis and salts. It is not resistant to chlorinated biphenyls and oxidizing acids, oxidants, Aqua regia, hydrogen peroxide and sodium hypochlorite.

PPS has good radiation resistance and radiation resistance up to Gy 1*108. It is a new material that other engineering plastics can not match. It is the only ideal material for radiation resistance in the fields of electronics, electricity, machinery, instruments, aviation, aerospace and military, especially in the field of atomic bomb and neutron bomb.

The chemical structure of PPS itself is quite stable, and it contains sulfur, the flame retardant element. Therefore, PPS has excellent flame resistance. The specimens were ignited and the flow rates of oxygen and nitrogen were adjusted to observe the combustion. The oxygen concentration that keeps the specimen burning continuously is the limit oxygen index. The higher the value, the better the flame resistance. The limit oxygen index of pure PPS can be as high as 44, so it has excellent flame resistance. PPS with filler or glass fiber has higher limiting oxygen index and better flame resistance.

Pure PPS can pass UL-94 V0 when its thickness is 0.8 mm. Basically, except for a few grades such as super toughness series, the burnability of UL94 of various grades of PPS belongs to V-0 grade, which is the best rank in UL94 burnability. Super toughening PPS series contains some toughening agents, which will sacrifice some flame resistance.

Pure PPS and non-conductive PPS have excellent electrical insulation properties. The PPS grade added with carbon fibers has a relatively low volume resistance coefficient.