Polypropylene (PP) is one of the four major general-purpose plastics (PE, PP, PVC, PS), and its output occupies the second place in the world, and domestic output cannot be underestimated. According to the original synthesis, polypropylene is divided into homopolypropylene (PPH) and copolymer polypropylene. The copolymer polypropylene can be divided into block copolymer polypropylene (PPB) and random copolymer polypropylene (PPR).
Homopolypropylene (PPH)
It is polymerized from a single propylene monomer, and the molecular chain does not contain other monomers. The molecular chain has high regularity, high crystallinity of the material, brittle material, and poor impact performance.
Block copolymer polypropylene (PPB)
The ethylene monomer in the molecule is inserted into the polypropylene molecular chain in the form of a chain segment. The ethylene content is relatively high, generally 7% to 15%. The material has better impact resistance and lower transparency.
Random copolymer polypropylene (PPR)
The ethylene monomers in the molecule are randomly and randomly distributed in the polypropylene molecular chain. The random addition of ethylene reduces the crystallinity and melting point of polypropylene and improves the impact resistance of the material.
The copolymer is made by co-polymerizing two or more monomers. The binary copolymer composed of two structural units A and B can be divided into random type, alternating type, block type, and graft type according to the connection mode.