Nylon
Nylon
is the common name (whose origin is disputed) for
high-molecular weight polyamides - crystalline
polymers typically produced by the condensation
of a diacid and a diamine. There are several
types, numeric suffixes referring to the number
of carbon atoms present in the molecular
structures of the amine and acid respectively (or
a single suffix if the amine and acid groups are
part of the same molecule). The principal
materials for plastics are nylon 66 (derived from
hexamethylene diamine and adipic acid) and nylon
6 (from caprolactam) - more specialised nylon 11
(aminoundecanoic acid), nylon 12 (aminolauric
acid) and nylon 610 (hexamethylene diamine and
sebacic acid).
The most familiar
use for nylon is, of course, as a textile yarn
and, in thicker section as monofilaments for
brushes, etc. However, nylon 66 and 6 in
particular are very important engineering
thermoplastics. Their dominant feature is a much
higher softening temperature than other polymers
in this category. They are also exceptionally
tough and wear resistant, with low friction
characteristics.
This range of
properties makes nylon a choice for technically
demanding injection moulded components, such as
in 'under-the-bonnet' automotive parts.
The natural colour
of nylon is waxy-white. As well as injection
mouldings it is also available in stock shapes
for machining into, for example, gearwheels and
as a powder for tough coating applications such
as handrails.
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