What is PVC?

Date:2020-06-24 16:12:46 星期三
Summary:

Polyvinyl chloride, referred to as PVC (Polyvinyl chlor […]

Polyvinyl chloride, referred to as PVC (Polyvinyl chloride) in English, is a initiator of vinyl chloride monomer (VCM) in peroxides, azo compounds, etc.; or according to the mechanism of free radical polymerization under the action of light and heat Polymerized polymer. Vinyl chloride homopolymer and vinyl chloride copolymer are collectively referred to as vinyl chloride resin.
PVC is a white powder with an amorphous structure. The degree of branching is relatively small, the relative density is about 1.4, the glass transition temperature is 77~90℃, and it begins to decompose around 170℃. [1] The stability to light and heat is poor, above 100℃ or After prolonged exposure to sunlight, it will decompose to produce hydrogen chloride, and further automatically catalyze the decomposition, causing discoloration, and the physical and mechanical properties also rapidly decline. In practical applications, stabilizers must be added to improve the stability of heat and light.
The molecular weight of industrially produced PVC is generally in the range of 50,000 to 110,000, with a large polydispersity, and the molecular weight increases with the decrease of the polymerization temperature; without a fixed melting point, it begins to soften at 80 to 85°C and becomes viscoelastic at 130°C , 160 ~ 180 ℃ began to change to viscous fluid state; has good mechanical properties, tensile strength of about 60MPa, impact strength of 5 ~ 10kJ/m2; has excellent dielectric properties.
PVC used to be the largest general-purpose plastic in the world, and it is widely used. It is widely used in construction materials, industrial products, daily necessities, floor leather, floor tiles, artificial leather, pipes, wires and cables, packaging films, bottles, foam materials, sealing materials, fibers, etc.

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