Welding rod of PP (partially crystalline thermoplastic - group of polyolefins)
Polypropylene (abbreviation PP) is a thermoplastic produced by chain polymerization of propene. It belongs to the group of polyolefins, is semi-crystalline and non-polar. Its properties are similar to polyethylene, but it is slightly harder and more heat resistant. Polypropylene is the second most widely used standard plastic and is often used for packaging, but also in container construction. Polypropylene has good resistance to chemicals. It is resistant to greases, many solvents, acids and alkalis, and alcohol. PP hardly absorbs water. Gases diffuse through PP. There are three types of polypropylene: homopolymer has particularly good stiffness, copolymer has high impact strength and random copolymer has high transparency.