Poly(ethy1ene terephthalate), PET, is a semicrystalline thermoplastic polymer which has proven to be extremely valuable as a raw material for the production of fibers and oriented film products. Yarns and fabrics manufactured from PET polyester fibers are used in everything from clothing to heavy-duty industrial fabrics and load-bearing reinforcements. PET films are widely used for food packaging, and PET bottles for carbonated beverages have become commonplace.