聚氯乙烯的主要分类(The main classification of polyvinyl chloride)
聚氯乙烯（PVC），是氯乙烯单体（VCM）在过氧化物、偶氮化合物等引发剂或在光、热作用下按自由基聚合反应机理聚合而成的聚合物。氯乙烯均聚物和氯乙烯共聚物统称之为氯乙烯树脂。
根据应用范围的不同，PVC可分为：通用型PVC树脂、高聚合度PVC树脂、交联PVC树脂。通用型PVC树脂是由氯乙烯单体在引发剂的作用下聚合形成的；高聚合度PVC树脂是指在氯乙烯单体聚合体系中加入链增长剂聚合而成的树脂；交联PVC树脂是在氯乙烯单体聚合体系中加入含有双烯和多烯的交联剂聚合而成的树脂。
根据氯乙烯单体的获得方法来区分，可分为电石法、乙烯法和进口（EDC、VCM)单体法（习惯上把乙烯法和进口单体法统称为乙烯法）。
根据聚合方法，聚氯乙烯可分为四大类：悬浮法聚氯乙烯、乳液法聚氯乙烯、本体法聚氯乙烯、溶液法聚氯乙烯。悬浮法聚氯乙烯是产量最大的一个品种，约占PVC总产量的80%左右。悬浮法聚氯乙烯按绝对黏度分六个型号：XS-1、XS-2……XS-6；XJ-1、XJ-2……、XJ-6。型号中各字母的意思：X-悬浮法；S-疏松型；J-紧密型。
根据增塑剂含量的多少，常将PVC塑烯塑料分为：无增塑PVC，增塑剂含量为0；硬质PVC，增塑剂含量小于10%；半硬质PVC，增塑剂含量为10-30%；软质PVC，增塑剂含量为30-70%；聚氯乙烯糊塑料，增塑剂含量为80%以上。
Polyvinyl chloride (PVC) is a polymer polymerized by vinyl chloride monomer (VCM) in peroxides, azo compounds and other initiators or under the action of light and heat according to the mechanism of free radical polymerization.Vinyl chloride homopolymers and vinyl chloride copolymers are collectively referred to as vinyl chloride resins.
According to the different application range, PVC can be divided into: general-purpose PVC resin, high polymerization degree PVC resin, cross-linked PVC resin.General-purpose PVC resin is formed by polymerization of vinyl chloride monomer under the action of initiator;High polymerization degree PVC resin refers to the resin polymerized by adding chain extender to the vinyl chloride monomer polymerization system;Crosslinked PVC resin is a resin polymerized by adding a crosslinker containing diene and polyene to a vinyl chloride monomer polymerization system.
According to the method of obtaining vinyl chloride monomer, it can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (it is customary to refer to ethylene method and imported monomer method as ethylene method).
According to the polymerization method, polyvinyl chloride can be divided into four categories: suspension polyvinyl chloride, emulsion polyvinyl chloride, bulk polyvinyl chloride, solution polyvinyl chloride. Suspended polyvinyl chloride is the largest variety, accounting for about 80% of the total PVC production. Suspended polyvinyl chloride is divided into six models according to absolute viscosity: XS-1, XS-2... XS-6； XJ-1、XJ-2......、XJ-6。 The meaning of each letter in the model number: X-suspension method; S-loose type; J-compact type.
According to the amount of plasticizer content, PVC plasticene plastics are often divided into: non-plasticized PVC, plasticizer content is 0; Rigid PVC, plasticizer content less than 10%; Semi-rigid PVC with plasticizer content of 10-30%; Flexible PVC with a plasticizer content of 30-70%; Polyvinyl chloride paste plastic, plasticizer content is more than 80%.