Polyvinyl chloride (Polyvinyl chloride chloride) is an initiator of the vinyl chloride chloride monomer (VCM) in peroxides, azo compounds, etc. Or under the action of light, heat, according to the free radical polymerization reaction mechanism polymerization and become a polymer.
PVC for amorphous structure of white powder, branched degree is small, relative density 1.4, glass transition temperature of 77 ~ 90 ℃, 170 ℃ or so began to decompose, poor stability to heat and light, in more than 100 ℃ or the sun for a long time, will decompose and produce hydrogen chloride, and further automatic catalytic decomposition, cause discoloration, physical and mechanical properties also fell rapidly, must be added in the practical application of stabilizers in order to improve the stability of heat and light.
The molecular weight of PVC produced by industry is generally within the range of 50,000 ~ 110,000, and it has a relatively large polydispersity. The molecular weight increases with the decrease of polymerization temperature. Without fixed melting point, it began to soften at 80 ~ 85℃, became viscoelastic at 130℃, and became viscous at 160 ~ 180℃. Good mechanical properties, tensile strength of about 60MPa, impact strength of 5 ~ 10kJ/m2; Excellent dielectric properties.
PVC used to be the world's largest production of general plastic, the application is very wide. In building materials, industrial products, daily necessities, floor leather, floor tile, artificial leather, pipe, wire and cable, packaging film, bottle, foam materials, sealing materials, fiber and other aspects are widely used.