Polyethylene terephthalate
Polyethylene terephthalate, (C10H8O4)n (PET) – a polymer from the group of polyesters, obtained by step-growth polymerization using dimethyl terephthalate (DMT) and ethylene glycol (EG).
Melted polyethylene terephthalate, after rapid cooling, solidifies to form a glasslike, amorphous mass. Especially in elevated temperatures (100-245oC), this mass undergoes a quite rapid crystallization process and transforms into a microcrystalline body with undirected structure. Fibres or films made from polyethylene terephthalate, stretched at a temperature higher than the glass transition temperature, undergo permanent deformation coupled with orientation of both macromolecules and crystallites along the direction of the stretching force.
PET is a widely used plastic for the manufacture of containers, bottles, packages, small shapes (e.g. transparent key buttons) and housings for electronic devices. In addition, fibres are also woven to manufacture cloths such as polartec (polar). Copolymers of terephthalate also include dacron and tergal – fibres used to manufacture woven materials with cloth-like mechanical properties.
Antimony trioxide is used as a catalyst in the manufacture of the PET polymer.