Polyethylene terephthalate (PET) bụ polymer nke nwere ọkara kristal nke nwere nguzogide kemịkalụ dị mma, mgbaze ngagharị na ntụgharị.Ihe mejupụtara polymer mejupụtara nkeji ugboro ugboro dị ka egosiri na eserese 1. Nkeji ọ bụla nwere ogologo anụ ahụ nke ihe dịka 1.09 nm na ịdị arọ molecular nke ~ 200.Mgbe emepụtara ya site na mmeghachi omume nke terephthalic acid na ethylene glycol, a na-ekpuchi ya n'aka ekpe site na H- na aka nri site na-OH.Polymerization si otú a na-esonyere mmepụta mmiri nke a na-ewepụ n'okpuru okpomọkụ dị elu na oghere.N'ihi ya, ọnụnọ nke mmiri na steeti gbazere ga-ngwa ngwa depolymerize ihe owuwu nke mere na nke ọma ihicha nke polima tupu agbaze spinning nke eriri dị mkpa.

Mgbanaka na-esi ísì ụtọ jikọtara ya na obere aliphatic yinye na-eme ka polymer bụrụ molecule siri ike ma e jiri ya tụnyere polymer aliphatic ndị ọzọ dị ka polyolefin ma ọ bụ polyamide.Enweghị mmegharị nke akụkụ na ụdọ polymer na-ebute nkwụsi ike dị elu nke okpomọkụ.Polymer ọkwa akwa ga-enwe nkezi ọnụọgụ 100 ikwugharị nkeji kwa molecule nke mere na ogologo ogologo nke yinye polymer a na-ahụkarị bụ ihe dịka 100nm na ịdị arọ molekụla ihe dị ka 20,000.Ọkwa dị elu nke polymerization na-arụpụta eriri ike dị elu mana mgbaze viscosity na nkwụsi ike nke agbaze na ọbụna obere mmiri mmiri na-akpata mbibi hydrolytic.A na-eme nha nke nkezi ogo polymerization ma ọ bụ site na viscosity a wụrụ awụ (site n'ịtụ ụda nrụgide site na orifice calibrated) ma ọ bụ viscosity nke polymer diluted na ihe mgbaze kwesịrị ekwesị.Nke ikpeazụ bụ ihe atụ nke ogologo yinye polymer mara dị ka viscosity intrinsic ma ọ bụ IV na uru maka polymer ọkwa ọkwa bụ 0.6 dl/g na 60/40 w / w ngwakọta nke phenol na tetrachloroethane mgbaze.IV na mgbaze ikpeazụ metụtara Mv (Viscosity nkezi molecular arọ) nke polymer site na akara Mark Howink (Nha nhata 1).