Thermoset plastics such
as amino, epoxy, phenolic, and unsaturated
polyesters, are so named because they
experience a chemical change during processing
and become "set", hard solids.
Thermosets are highly cross-linked
polymers that have a molecular mesh or
network of polymer chains like a three-dimensional
version of a net. Thermosets undergo a
chemical as well as a phase change when
they are heated. Once cured they cannot
be melted or remolded and are resistant
to solvents - that is once they are formed
they are 'set' (hence the name).
Thermoset plastics, because
of their tightly crosslinked structure,
resist higher temperatures and provide
greater dimensional stability than do
most thermoplastics. Thermosets are tough,
durable with high temperature performance,
and have found applications in a wide
variety of fields including electronic
chips, fibre-reinforced composites, polymeric
coatings, spectacle lenses and dental
fillings.
For more specific examples
of thermoset resins and their uses browse
the following pages.
