Page 41 - Curriculum Visions Dynamic Book

 Filaments of polyester fibre are wound on to drums in a modern synthetic fibre factory.
extrusion: forming a shape by pushing it through a die. For example, toothpaste is extruded through the cap (die) of the toothpaste tube.
synthetic: does not occur naturally, but has to be manufactured.
Also... Esters
The word “ester” refers to a group of organic compounds that includes many flavourings and also common solvents and plastics such as acetate (used as a backing on photographic film, for example). Esters are often made by reacting acids with alcohols.
Polyesters are polymers made with ester groups. Polymers used for coatings are made so that the polymers are cross-linked
(as are rubbers). The form of polyester used for fibres is
called polythene–terephthalate.
Polyesters can also be stretched into films such as the base of photographic films (when they are usually referred to simply as “acetate”). The
sails on boats are also usually made from
polyesters because of their strength and resistance to rotting.
 This photographic film is made from an ester, normally called acetate.
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