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polyolefins(pŏl'ēōl`əfən), group of plasticsplastic,
any organic material with the ability to flow into a desired shape when heat and pressure are applied to it and to retain the shape when they are withdrawn. Composition and Types of Plastic
..... Click the link for more information. that are polymerspolymer
, chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer,
..... Click the link for more information. of various alkenesalkene
, any of a group of aliphatic hydrocarbons whose molecules contain one or more carbon-carbon double bonds (see chemical bond). Alkenes with only one double bond have the general formula CnH2n.
..... Click the link for more information. , or olefins. The most important are polyethylenepolyethylene
, widely used plastic. It is a polymer of ethylene, CH2=CH2, having the formula (-CH2-CH2-)n, and is produced at high pressures and temperatures in the presence of any one of several catalysts, depending
..... Click the link for more information. and polypropylenepolypropylene
, plastic noted for its light weight, being less dense than water; it is a polymer of propylene. It resists moisture, oils, and solvents. Since its melting point is 121°C; (250°F;), it is used in the manufacture of objects that are sterilized in the course of
..... Click the link for more information. .