Polypropylene (PP) is a thermoplastic resin polymerized from propylene monomer. It is a colorless, odorless and non-toxic white translucent waxy granular material. Polypropylene is divided into homopolymers and copolymers, of which homopolymers are isotactic, syndiotactic and random. Homopolymer isotactic polypropylene is the most used. Polypropylene has good thermal performance.