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Vinyl
(Polyvinyl Chloride or PVC):
In addition to its stable physical properties, PVC has
excellent transparency, chemical resistance, long-term
stability, good weatherability, flow characteristics
and stable electrical properties. The diverse slate
of vinyl products can be broadly divided into rigid
and flexible materials. Rigid applications, accounting
for 60 percent of total vinyl production, are concentrated
in construction markets which include pipe and fittings,
siding, carpet backing and windows. Bottles and packaging
sheet are also major rigid markets. Flexible vinyl is
used in wire and cable insulation, film and sheet, floor
coverings, synthetic-leather products, coatings, blood
bags, medical tubing and many other applications. (Adapted
from Modern Plastics Encyclopedia 1995).
Vicat softening
temperature
Vicat softening temperature shows heat softening characteristics
of thermoplastics. Flat specimen are placed in a temperature
regulated heating bath, a needle type, loaded penetrator
is set on the specimen surface and bath temperature
is raised at a constant rate. The temperature of the
bath at which the penetration of the needle has reached
a predefined level is the Vicat softening temperature
of the material.
Vitrification
Point at which a system becomes a glassy solid, and
its molecules become immobilized, except for vibrations.
At vitrification, the reaction rate (kinetics) drops
off quickly.
Vulcanization
An irreversable process during which a rubber compound,
through a change in it's chemical structure (for example,
cross-linking), becomes less plastic and more resistant
to swelling by organic liquids and elastic properties
are conferred, improved or extended over a greater range
of temperature.
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Plastic
Brief