Polyethylene terephtalate
| PET | |
|---|---|
| Density | 1370 kg/m3 |
| Young modulus(E) | 2800–3100 MPa |
| Tensile strength(σt) | 55–75 MPa |
| Elongation @ break | 50–150% |
| notch test | 3.6 kJ/m2 |
| Glass temperature | 75 °C |
| melting point | 260 °C |
| Vicat B | 170 °C |
| Thermal conductivity | 0.24 W/m.K |
| linear expansion coefficient (α) | 7×10−5/K |
| Specific heat (c) | 1.0 kJ/kg.K |
| Water absorption (ASTM) | 0.16 |
| Price | 0.5–1.25 €/kg |
| source: A.K. van der Vegt & L.E. Govaert, Polymeren, van keten tot kunstof, ISBN 90-407-2388-5 | |
Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family. The chemical industry makes it. It is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. It is one of the most important raw materials used in man-made fibers. It is also used as the dielectric in multi-purpose capacitors (K73-16 series).
Depending on its processing and thermal history, it may exist both as an amorphous (transparent) and as a semi-crystalline (opaque and white) material. Its monomer can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct or the transesterification reaction between ethylene glycol and dimethyl terephthalate with methanol as a byproduct. Polymerization is through a polycondensation reaction of the monomers (done immediately after esterification/transesterification) with ethylene glycol as the byproduct (the ethylene glycol is recycled in production).
The majority of the world's PET production is for man-made fibers (in excess of 60%) with bottle-making accounting for around 30% of global demand. In discussing cloth uses, PET is generally referred to as simply "polyester" while "PET" is used most often to refer to packaging applications.
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A PET bottle (containing mineral water)
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sails are often made of PET-fibers.
