What is Polyvinyl chloride?
2017-03-29 14:32:51
Polyvinyl chloride (PVC) is one of the five general plastics (PE, PP, PVC, ABS, PS). PVC is a thermoplastic resin, which is formed by the polymerization of vinyl chloride in the presence of initiator. Copolymer of vinyl chloride and vinyl chloride copolymer.
Polyvinyl chloride has good mechanical properties, tensile strength of about 60MPa, impact strength of 5 ~ 10kJ/m2, and excellent dielectric properties. But the stability of light and heat, at 100 DEG C or after long time exposure to sunlight, will decompose and produce hydrogen chloride, and further Autocatalytic Decomposition, causing discoloration, physical and mechanical properties also decreased rapidly, so the heat stabilizer must be added to provide high stability to heat and light in the production of PVC products, extend the use of life.
According to the different production methods, PVC can be divided into: General PVC resin, high polymerization degree PVC resin, crosslinked PVC resin. The general PVC resin by polymerization of vinyl chloride monomer is formed under the action of initiator; high degree of polymerization of PVC resin is resin in the polymerization of vinyl chloride monomer added to the system, the chain growth polymerization crosslinking agent; PVC resin is added to the resin crosslinking agent containing dienes and polyenes in vinyl chloride monomer polymerization polymerization system.
According to the method to distinguish the vinyl chloride monomer, can be divided into electric stone, and imported ethylene (EDC, VCM) monomer method (on the habits of the ethylene monomer and import system called ethylene method).
According to the polymerization method, polyvinyl chloride can be divided into four categories: suspension polyvinyl chloride (PVC), emulsion polyvinyl chloride (PVC), bulk polyvinyl chloride (PVC), solution method polyvinyl chloride (PVC). Suspension polyvinyl chloride (PVC) is one of the largest varieties, accounting for about 80% of the total output of PVC. The following chart lists the basic properties of these four types of pvc.