Polyvinyl chloride, English abbreviation PVC (polyvinyl chloride), is vinyl chloride monomer (calendered chloride monomer, VCM) in peroxide, azo compounds, such as initiator, or under the light, thermal action polymerization of free radical polymerization of polymers. Vinyl chloride homopolymer and vinyl chloride copolymer are called vinyl chloride resins.
PVC is a white powder with amorphous structure, the degree of small support, relative density of about 1.4, glass temperature 77~90℃,170℃ began to decompose , light and heat stability is poor, in 100 ℃ or over a long period of sunlight exposure, will decompose and produce hydrogen chloride, and further automatic catalytic decomposition, causing discoloration , physical mechanical properties are also rapidly declining, and stabilizers must be added in practical applications to improve the stability of heat and light.
The molecular weight of PVC in industrial production is generally in the range of 50,000 ~11, it has larger dispersibility, and the molecular weight increases with the decrease of polymerization temperature. No fixed melting point, 80~85℃ began to soften, 130 ℃ into viscoelastic State, 160~180℃ began to change into viscous flow; Tensile strength of about 60MPa, impact intensity 5~10kj/m2, excellent dielectric properties.
PVC has been the world's largest production of general-purpose plastics, widely used. In the building materials, industrial products, daily necessities, flooring leather, floor tiles, imitation leather, pipe, wire and cable, packaging film, bottles, foam materials, sealing materials, fibers and other aspects are widely used.