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Properties of Plastics:
Plastics possess a wide variety of useful
properties and are relatively inexpensive to produce. They are
lighter than many materials of comparable strength, and unlike
metals and wood, plastics do not rust or rot. Most plastics can be
produced in any color. They can also be manufactured as clear as
glass, translucent (transmitting small amounts of light), or opaque
(impenetrable to light).
Plastics have a lower density than that
of metals, so plastics are lighter. Most plastics vary in density
from 0.9 to 2.2 g/cm3 (0.45 to 1.5 oz/cu in), compared to steel’s
density of 7.85 g/cm3 (5.29 oz/cu in). Plastic can also be
reinforced with glass and other fibers to form incredibly strong
materials. For example, nylon reinforced with glass can have a
tensile strength (resistance of a material to being elongated or
pulled apart) of up to 165 Mega Pascal (24,000 psi).
Plastics have some disadvantages. When
burned, some plastics produce poisonous fumes. Although certain
plastics are specifically designed to withstand temperatures as high
as 288° C (550° F), in general plastics are not used when high heat
resistance is needed. Because of their molecular stability, plastics
do not easily break down into simpler components. As a result,
disposal of plastics creates a solid waste problem
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