Polypropylene molecules contain methyl groups, which can be divided into isotactic polypropylene, atactic polypropylene and syndiotactic polypropylene according to the arrangement of methyl groups. When the methyl groups are arranged on the same side of the main chain, it is called isotactic polypropylene; if the methyl groups are randomly distributed on both sides of the main chain, it is called atactic polypropylene; when the methyl groups are arranged alternately on both sides of the main chain, it is called syndiotactic. polypropylene. In the general production of polypropylene resin, the content of isotactic structure (called isotacticity) is about 95%, and the rest is atactic or syndiotactic polypropylene. The polypropylene resin currently produced in China is classified according to the melt index and the additives added.

Atactic polypropylene is a by-product of the production of isotactic polypropylene. Atactic polypropylene is produced in the production of isotactic polypropylene, and isotactic polypropylene is separated from atactic polypropylene by a separation method.

Atactic polypropylene is a highly elastic thermoplastic material with good tensile strength. It can also be vulcanized like ethylene-propylene rubber.