Polytetrafluoroethylene， Abbreviated as PTFE, also known as Teflon, commonly known as the "Plastic King", it is a polymer made by polymerizing tetrafluoroethylene as a monomer. Its chemical formula is (C2F4) n, and it has excellent heat and cold resistance. It can be used for a long time at -180~260 º C. This material has the characteristics of acid and alkali resistance, resistance to various organic solvents, and is almost insoluble in all solvents. At the same time, polytetrafluoroethylene has the characteristic of high temperature resistance, and its friction coefficient is extremely low. Therefore, in addition to its lubricating effect, it has also become an ideal coating for easy cleaning of the inner layer of water pipes.

PET， The chemical formula is (C10H8O4) n, which is synthesized by exchanging dimethyl terephthalate with ethylene glycol ester or esterifying terephthalic acid with ethylene glycol to form dihydroxyethyl terephthalate, followed by condensation reaction. Belonging to crystalline saturated polyester, it is a highly crystalline polymer with a milky white or light yellow color, smooth and glossy surface. It is a common resin in daily life and can be divided into APET, RPET, and PETG.

Ethylene tetrafluoroethylene copolymer is a chemical substance, and ETFE is the strongest fluoroplastic. It maintains the good heat resistance, chemical resistance, and electrical insulation properties of PTFE, while greatly improving radiation resistance and mechanical properties. Its tensile strength can reach 50MPa, nearly twice that of polytetrafluoroethylene.