聚对苯二甲酸乙二醇酯Polyethylene terephthalate

主链中刚性的苯环和极性酯基使 PET 的玻璃化温度约 70–80 °C、熔点约 250–260 °C。PET 结晶速度较慢，迅速冷却可得透明的非晶态，加热拉伸可诱导取向结晶，大幅提高强度和阻隔性——饮料瓶就是用注坯后双向拉伸吹塑制成的。涤纶纤维强度高、弹性好、抗皱、易洗快干。

Rigid benzene rings and polar ester groups give PET a glass transition near 70–80 °C and a melting point near 250–260 °C. It crystallises slowly, so quenching gives clear amorphous material, while stretching when warm induces oriented crystallisation that greatly raises strength and barrier performance; bottles are made by injection-moulding a preform and stretch blow moulding it. Polyester fibre is strong, resilient, crease-resistant and quick-drying.

1941 年英国卡利科印花工人协会的温菲尔德和迪克森在卡罗瑟斯工作的基础上合成了 PET，并申请专利。ICI 以 Terylene、杜邦以 Dacron 商标生产纤维，1950 年代迅速普及。1973 年杜邦的怀斯发明 PET 拉伸吹塑饮料瓶，取代了玻璃瓶。中国是全球最大的涤纶生产国。

In 1941 Whinfield and Dickson of the Calico Printers' Association in Britain, building on Carothers's work, synthesised and patented PET. ICI made the fibre as Terylene and DuPont as Dacron, and it spread rapidly in the 1950s. In 1973 Nathaniel Wyeth at DuPont patented the stretch-blown PET drinks bottle, which displaced glass. China is the world's largest producer of polyester fibre.

PET（树脂识别码 1）是回收率最高的塑料之一，回收瓶片可重新纺丝制成服装和地毯纤维，或经固相增黏重新制成食品级瓶（瓶到瓶回收）。化学回收可通过醇解或糖酵解解聚为对苯二甲酸双羟乙酯，再重新聚合。2016 年日本科学家从回收厂分离出能降解 PET 的大阪堺菌（Ideonella sakaiensis）及其 PET 水解酶。

PET, resin code 1, is among the most recycled plastics: flakes from bottles are respun into clothing and carpet fibre or upgraded by solid-state polycondensation into food-grade bottles again. Chemical recycling depolymerises it by alcoholysis or glycolysis to bis(hydroxyethyl) terephthalate for repolymerisation. In 2016 Japanese scientists isolated Ideonella sakaiensis, a bacterium from a recycling plant that degrades PET with its own PETase enzyme.