Page 44 - Curriculum Visions Dynamic Book

Almost all kinds of clothing are made with polyester. It is also used in drapes, upholstery, carpets, bed linen, for ropes and nets, for thread, for tyre cord, for sails, and as fibrefill for thermal clothing, pillows, and furniture.
Polyester molecules are regular and straight, so the chains link together well. However, they can still melt. Polyester is thermoplastic material, unlike many plastics whose chains prevent this, and so they decompose or char (they are thermosetting plastics). Polyester can therefore be melted and re-formed, perhaps as transparent bottles or as more fibres.
Polyester has a high enough melting point to be untroubled by washing and warm (not hot) ironing. This is also important because it allows it to take a permanent-press finish. That is because, in order to remain in the shape made during manufacture, the fibre must not be reheated to a temperature called its “glass transition temperature.” Below this temperature the polyester will not change shape, but above this critical point it is easy to reshape. So polyester can be made into the desired
fabric at a high temperature that is still below the melting point, but the pleats or other finish will not come out during normal washing, ironing, and drying temperatures because they do not reach the glass transition temperature.
(Right) Acrylic is used as a substitute for wool – in sweaters and blankets, filters, flame-resistant awnings, tents, artificial fur, and children’s sleepwear.
(Below) In the summer of 1952 “wash and wear” was coined to describe a new blend of cotton and acrylic. Now everyone expects this as a property of the clothes they wear.
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