Page 42 - Curriculum Visions Dynamic Book

Polyester fibre
Polyester makes up over half of all man-
made fibre production. Its most common
form is called PET or PETE (polyethene terephthalate). A considerable amount of polyester fibre is produced by recycling PET soft drink bottles and thus saving on petroleum supplies and avoiding landfill problems.
PET is made by reacting the chemical
ethylene glycol with terephthalic acid. A special chemical called a catalyst is also needed to help
form the polymer. The reaction is carried out at high temperature and in a vacuum. PET is melted and then extruded through a spinneret.
Polyester is so widely used because it is strong, it
does not change shape or shrink when washed, and
(Left) A colourful polyester fibre bobbin
used in sewing. Common or trade
names for polyester fibres include
Dacron®, Terylene®, and Trevira®.
it is easily washed and quick drying. It also does not (Below) A polyester can be
change its texture when wet, does not easily crease, does not rot, and can be permanently pressed.
produced from a reaction between a dicarboxylic acid and a glycol or dialcohol. The product is a
Polyester does not, however, absorb water, and so condensation polymer.
it cannot be dyed with water-based natural dyes.
In the example below, terephthalic acid reacts with ethylene glycol to produce a polyester with the trade name Dacron®.
Terephthalic acid
Ethylene glycol
Section of Dacron® polymer chain
Water
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