2021-10-19 Polypropylene is a polymer formed 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, [1] It is flammable, with a melting point of 189℃, softening at about 155℃, and the operatin