polyethylene terephthalate (aka pet, pete or the obsolete petp or pet-p) is a thermoplastic polymer resin of the polyester family. the chemical industry makes it. it is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. it is one of the most important raw materials used in man-made fibers. it is also used as the dielectric in multi-purpose capacitors (k73-16 series).