Polypropylene is a polymer obtained by addition polymerization of propylene. It is a white waxy material with a transparent and light appearance. The chemical formula is (C3H6)n, the density is 0.89～0.91g/cm3, It is flammable, the melting point is 189°C, and it softens at about 155°C. The operating temperature range is -30～140°C. It is resistant to corrosion by acid, alkali, salt solution and various organic solvents below 80 °C, and can be decomposed under high temperature and oxidation.