Polypropylene, a thermoplastic resin made from the polymerization of propylene. The positions of the methyl groups are classified into isotactic polypropylene, atactic polypropylene, and syndiotactic polypropylene.
The methyl groups are arranged on the same side of the molecular backbone as isotactic polypropylene. If the methyl groups are disorderly arranged on both sides of the molecular backbone, they are called random polypropylenes. When the methyl groups alternate between the two sides of the molecular backbone, Polypropylene. In general industrial production of polypropylene resins, the isotactic structure content is about 95%, and the rest is random or syndiotactic polypropylene. Industrial products are mainly composed of isotactic substances. Polypropylene also includes copolymers of propylene and small amounts of ethylene. Usually translucent colorless solid, odorless and non-toxic. Due to the highly structured structure, the melting point can be as high as 167°C. Heat resistance, corrosion resistance, steam sterilization products is its outstanding advantages. Low density is the lightest universal plastic. The disadvantages are poor low-temperature impact resistance and easier aging, but they can be overcome by modification.
The copolymer PP material has a low heat distortion temperature (100°C), low transparency, low gloss, and low rigidity, but has a stronger impact strength, and the impact strength of PP increases as the ethylene content increases. . The Vicat softening temperature of PP is 150°C. Due to the high degree of crystallinity, this material has very good surface stiffness and scratch resistance. PP does not have the problem of environmental stress cracking.