Polysulphone
Much early space-age work in
the 1960s was aimed at the development of
thermoplastic polymers which could be processed
conveniently and produce components with some of
the properties of reinforced thermoset plastics.
Synthetic routes to polysulphones were found
independently by workers in 3Ms and Union Carbide
in the USA and the Plastics Division of ICI in
the UK. Polymer syntheses are complex and varied.
Early methods included reaction of a dihaloaryl
compound with an alkali metal diphenoxide and
also polysulphonylation processes using selected
solvents and catalysts.
Poly(phenylene sulphone) itself decomposes
before melting above 500°C but the introduction
of aryl-ether linkages in the polymer reduces the
softening temperature so that the material can
more easily be moulded.
The range of variants now available, filled
and unfilled, offers a choice of designed high
performance products with many superior long term
properties. As a class polysulphones are very
stable chemically and mechanically and have
excellent thermal, electrical and creep resistant
properties over a wide temperature range.
Weathering is poor but can be improved greatly
with selected pigments. The poly(ether sulphones)
have better stress crack resistance than poly(phenylene
sulphone). With reinforcing fibres, such as glass
and carbon, very demanding applications can be
met such as continuous performance under stress
above 200°C.
The advantages of this polymer family have
been seen in aerospace, automotive, electrical
and lighting systems, business machines and other
demanding conditions of sustained durability.
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