Polyethylene terephthalate is a semi-crystalline polyester, usually know with the acronym PET. Main characteristics of this material are a great dimensional stability, a very low moisture and water absorption and the excellent coefficient of friction and wear resistance. Load capacity without deformation is remarkable too.
PET is one of the most performant thermoplastic materials. Although that, it is really important to accurately know all its characteristics, to be able to analyse the application circumstances and understand strength and weakness points.
Compared to PA or POM, dimensional stability of polyethylene terephthalate results much better and higher. Stability is a result of a very low moisture and water absorption and, in addition to that, of a great crystallinity of the material which, at the same time, transform it in a very fragile material.
Main strength points of PET are for sure its rigidity and wear resistance. These two factors, linked together with a great load capacity and an excellent coefficient of friction, are the ideal characteristics to consider it really suitable for sliding applications. Lubrification is commonly not necessary anyway, if better performance are needed, an easy application of oil, grease or water would increase component life time.
Temperature range goes from 0 to 100° C, anyway you need to pay attention to hydrolysis, which begin starting from 70°C.
It is important to remind that one the worst weakness point of PET is its fragility. This polyester, due to its crystallinity, is highly breakable. Machined components made out of this material are really fragile and chipping could be common.
Polyethylene terephthalate is resistant to many chemical, such as: aliphatic and aromatic carbon hydrogen, ether, esther and aldheide as well as to oils and greases. Inorganic acids, caustic solutions, basis, hot water and steam could attack it.
Polyethylene terephthalate results suitable to come into contact to foodstuff and it complies EC 1935/2004, EC 2023/2006, EU 10/2011 and FDA.
PET is usually available in sheets, rods and tubes. Most common brand name are: