Polyethylene

polyethylene

[¦päl·ē′eth·ə‚lēn]

(organic chemistry)

ethylene resin

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

polyethylene

A tough, light, flexible thermoplastic used in the form of sheeting and film for packaging, damp-proofing, and as a vapor barrier.

See also: Plexiglas

Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

polyethylene

A thermoplastic material often used in electrical insulation or in sheet form for dampproofing.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Polyethylene

 

[—CH₂—CH₂—]_n, a white thermoplastic polymer. It is produced industrially by polymerization of ethylene at high pressure (low-density polyethylene) or at low or medium pressure (high-density polyethylene).

The structure and properties of polyethylene are determined by the method of preparation. The average molecular weight of the most common brands is 30,000–800,000; crystallinity and density at 20°C are 50 percent and 0.918–0.930 g/cm³, respectively, for low-density polyethylene and 75–90 percent and 0.955–0.968 g/cm³ for high-density polyethylene. An increase in density is accompanied by an increase in hardness, modulus of bending resilience, yield point, and chemical stability. Polyethylene combines high tensile strength (10–45 meganewtons per sq m, or 100–450 kilograms-force per sq cm) with elasticity (ultimate elongation, 500–1,000 percent), and it has good electrical insulation properties (loss tangent, 2 × 10^–4 to 4 × 10^–4 at –120° to 120°C and 10–50 kilohertz). It is resistant to alkalies in any concentration, and also to organic acids, concentrated hydrochloric, and hydrofluoric acids, but it is attacked by nitric acid, chlorine, and fluorine. At temperatures above 80°C, it is soluble in aliphatic and aromatic hydrocarbons and their halogen derivatives. It is relatively stable upon exposure to radioactive emissions, and it is harmless. Its working temperature range is between –80°–120° to 60°–100°C.

Polyethylene is one of the least expensive polymers, combining valuable properties with workability by all known high-productivity methods used for thermoplasts. It is first among polymer plastics in world production.

Polyethylene is used to make films, pipes (including pipes for sewage and aggressive liquids, and also mains), sectional products, insulation for wires and cables, containers (large bottles, canisters, and tanks), electrolytic baths, sanitary products, and fibers; it is also widely used in engineering and agriculture, as well as domestically. Low-density polyethylene has become the most widespread. Products manufactured by means of chlorina-tion and sulfochlorination of polyethylene have also acquired commercial importance.

Polyethylene is manufactured in the USSR (high-density, or low-pressure, and low-density, or high-pressure, polyethylene) and abroad. Foreign brands of high-density polyethylene include Marlex (USA), Hostalen and Vestolen (Federal Republic of Germany), Hi-Zex (Japan), and Eltex (Italy). Foreign low-density brands include Bakelite and Alathon (USA), Alkathene (Great Britain), and Lupolen (Federal Republic of Germany). World production of polyethylene in 1973 was about 10 million tons.

REFERENCES

See references under .

I. N. ANDREEVA

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.