PET(Polyethylene terephthalate)
Polyethylene Teraphthalate (PET)Polyethylene terephthalate is the most common thermoplastic polymer resin of the polyester family and is used in fibers for clothing, containers for liquids and foods, thermoforming for manufacturing, and in combination with glass fiber for engineering resins.
PET consists of polymerized units of the monomer ethylene terephthalate, with repeating (C10H8O4) units. PET is commonly recycled, and has the number 1 as its recycling symbol.
Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer. The semicrystalline material might appear transparent (particle size < 500 nm) or opaque and white (particle size up to a few micrometers) depending on its crystal structure and particle size. Its monomer bis(2-hydroxyethyl) terephthalate can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct, or by 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 water as the byproduct.
PET is mostly used to create synthetic fibers and plastic bottles. You may recognize it on clothing labels under the name “polyester.”
Application: wiper arm and gear housings, headlamp retainer, engine cover, connector housings.