Polyvinyl Chloride (redirected from Polychloroethene)

polyvinyl chloride (PVC), thermoplastic that is a polymer of vinyl chloride. Resins of polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can be made. This plastic has found extensive use as an electrical insulator for wires and cables. Cloth and paper can be coated with it to produce fabrics that may be used for upholstery materials and raincoats.

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PVC

 in full polyvinyl chloride

Synthetic resin, an organic polymer made by treating vinyl chloride monomers with a peroxide. It may be blended with more rubbery polymers or copolymerized with other vinyls to obtain products with desired properties. PVC resin mixed with plasticizers (see Waldo Semon), stabilizers, and pigments is made into flexible articles (e.g., raincoats, toys, containers). Nonplasticized resin has been used for rigid products (e.g., water pipes, plumbing fittings, phonograph records). Concern over leaching of vinyl chloride into foods has resulted in restrictions on its use in food containers; its decomposition into hydrogen chloride when burned has also raised concerns. Today it is produced in larger quantities than any other plastic except polyethylene.

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polyvinyl chloride [¦päl·i′vīn·əl ′klȯr‚īd]

(organic chemistry)

(H₂CCHCl)_xPolymer of vinyl chloride; tasteless, odorless; insoluble in most organic solvents; a member of the family of vinyl resins; used in soft flexible films for food packaging and in molded rigid products such as pipes, fibers, upholstery, and bristles. Abbreviated PVC.

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polyvinyl chloride, PVC

A water-insoluble resin thermoplastic resin that is highly resistant to chemicals and corrosion; widely used for pipe fittings, piping in cold-water systems, and piping in sewage and waste lines.

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(hardware)

polyvinyl chloride - (PVC) A common plastic used for insulating and jacketing many wire and cable products.

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Polyvinyl Chloride 

(—CH₂—CHCl—)_n, a predominantly linear and thermoplastic polymer of vinyl chloride. It is a white plastic with a molecular weight of 6,000–160,000. Its degree of crystallinity is 10–35 percent, and its density at 20’C is 1.35–1.43 g/cm³. Polyvinyl chloride is physiologically harmless.

Polyvinyl chloride is rather strong, with a tensile strength of 40–60 meganewtons per sq m (MN/m²), or 400–600 kilograms-force per sq cm (kgf/cm²), and a flexural strength of 80–120 MN/m², or 800–1,200 kgf/cm². It is a good dielectric. It is limitedly soluble in ketones, esters, and chlorinated hydrocarbons and is resistant to the action of moisture, acids, alkalies, salt solutions, gasoline, kerosene, fats, alcohols, and industrial gases, such as NO₂, Cl₂, SO₃, and HF. Effective plasticizers for polyvinyl chloride include phthalates, phosphates, and sebacates. Polyvinyl chloride is resistant to oxidation and virtually incombustible. It has low heat resistance, with a Martens yield temperature of 50°-80°C. At temperatures above 100°C, it decomposes markedly and loses HC1, which may result in the polymer acquiring a color ranging from yellowish to black. Decomposition is accelerated in the presence of O₂, HCl, and some salts; it is also accelerated by strong mechanical action and by the action of ultraviolet, beta, and gamma radiation. Polyvinyl chloride is chlorinated to raise its heat resistance and improve its solubility.

In industry, polyvinyl chloride is obtained by the free-radical polymerization of a monomer in a bulk, emulsion, or suspension. Its major properties and uses are determined by the method of polymerization. Polyvinyl chloride produced by bulk or suspension polymerization is used in the production of rigid, semisoft, and soft (or plasticized) plastics, which are processed by pressing, injection molding, extrusion, or calendering. The pasty variety of emulsion polyvinyl chloride is used mainly in the production of such items as synthetic leathers and expanded plastics, which are made of plastisols and organosols.

Polyvinyl chloride is one of the most commonly used plastics. It is utilized in the production of more than 3,000 types of materials and items. It is used for various purposes in the elec-trotechnical, light, and food industries, in ship and heavy machine building, in agriculture and medicine, and in the production of construction materials.

World production of polyvinyl chloride in 1973 was about 8 million tons.

REFERENCES

See references under .

K. S. MINSKER