PET aka Polyethylene Terephthalate aka Polyester aka Mylar
is a hydrocarbon
based artificial plastic
and a member of the Polyester
family developed by American chemist Wallace Carothers
at Du Pont
during the 1920s and 1930s. Post-War improvements were made by British scientist
s Jon Whinfield
and J. T. Dickson
According to the US Federal Trade Commission is "at least 85% by weight of an ester of a substituted aromatic carboxylic acid, including but not restricted to substituted terephthalic units, p(-R-O-CO- C6H4-CO-O-)x and para substituted hydroxybenzoate units p(-R-O-CO- C6H4-O-)x." The para substituted hydroxybenzoate units in PET are ethylene group (CH2-- CH2).
PET is synthesized by reacting ethylene glycol (C2H6O2) and either terephthalic acid or it's metyl ester with the aid of the an antimony oxide catylyst. The reaction is carried out in a vaccum at high temperatures to achieve high molecular weight. The clear colorless molten polyester flows onto the casting wheel and forms into very small chips.
PET is a light, stable, chemical resistant material widely used as a packaging and small-scale construction material. It is widely recycled.