聚氯乙烯树脂

Polyvinyl chloride (PVC) is one of the earliest industrialized plastics, and its production volume is currently second only to polyethylene. PVC has been widely used in industry, agriculture, and daily life. It is a polymer compound formed by the polymerization of vinyl chloride. It is thermoplastic. It is a white or light yellow powder with a relative density of 1.35–1.40 and a chlorine content of 56%–58%. Its melting point is approximately 70–85°C. It is soluble in or swollen by ketones, esters, tetrahydrofurans, and chlorinated hydrocarbons. It has excellent chemical resistance. However, its thermal stability and light resistance are poor; it begins to decompose and release hydrogen chloride above 100°C or after prolonged exposure to sunlight, requiring the addition of stabilizers during plastic manufacturing. It has excellent electrical insulation properties and is non-flammable. It is used in the manufacture of plastics, coatings, and synthetic fibers. Depending on the amount of plasticizer added, it can be made into soft and rigid plastics. The former can be used to make transparent films (such as raincoats, tablecloths, packaging materials, agricultural films, etc.), artificial leather, foam plastics, and wire sheathing, etc. The latter can be used to make sheets, pipes, valves, and doors and windows. Suspension polymerization yields a powdered resin. Emulsion polymerization yields a paste-like resin. Both can be used to make soft or hard plastics.