Twenty Kinds of Plastics and Their Properties—(18) PS

18.PS polystyrene

Typical application range:

Product packaging, household products (tableware, pallets, etc.), electrical (transparent container, light source scatterer, insulating film, etc.).

Injection molding process conditions:

Drying process: dry process is not usually needed unless the storage is improper. If dry, it is suggested that the drying condition is 80 °C, 2~3 hours.
Melting temperature: 180~280 °C. For the flame retardant material, the upper limit is 250 °C.
Mold temperature: 40~50 °C.
Injection pressure: 200~600bar.
Injection speed: it is recommended to use fast injection speed.
Runner and gate: all regular types of gate can be used.

Chemical and physical properties:

Most commercial PS are transparent, non crystal materials. PS has very good geometric stability, thermal stability, optical transmission characteristics, electrical insulation characteristics and very slight hygroscopic tendency. It can resist water and dilute inorganic acids, but can be corroded by strong oxidizing acid, such as concentrated sulfuric acid, and can expand and deform in some organic solvents. The typical contraction rate is between 0.4~0.7%.