Polyethylene terephthalate (PET) ni polymer ya kimwe cya kabiri kristaline ifite imiti irwanya imiti, igenda ishonga kandi ikazunguruka.Polimeri igizwe nibice bisubiramo nkuko bigaragara ku gishushanyo cya 1. Buri gice gifite uburebure bwumubiri bugera kuri 1.09 nm nuburemere bwa molekile ya ~ 200.Iyo ikozwe mubisubizo bya aside terephthalic na Ethylene glycol, ifatwa ibumoso na H- n'iburyo na –OH.Polymerisation rero iherekezwa no kubyara amazi akurwa munsi yubushyuhe bwo hejuru na vacuum.Kubwibyo, kuba amazi muri leta yashongeshejwe bizahita bitesha agaciro imiterere kuburyo gukama neza polymer mbere yo gushonga kwa fibre birakenewe.

Impeta ya aromatic ifatanije nu munyururu mugufi wa alifatique ituma polymer iba molekile ikomeye ugereranije nizindi polimeri ya alifatique nka polyolefine cyangwa polyamide.Kubura kugendagenda kumurongo mumurongo wa polymer bivamo ubushyuhe buke cyane.Imyenda yo mu rwego rwa polymer izaba ifite impuzandengo yimibare 100 isubiramo kuri molekile kuburyo uburebure bwagutse bwurwego rusanzwe rwa polymer buba hafi 100nm hamwe nuburemere bwa molekile hafi 20.000.Urwego rwohejuru rwa polymerisation rutanga fibre ikomeye cyane ariko gushonga kwijimye no gushikama gushonga kugeza no ku gipimo gito cy’amazi bitera kwangirika kwa hydrolytike.Gupima impuzandengo yikigereranyo cya polymerisiyoneri bikorwa haba mubwiza bwashongeshejwe (mugupima umuvuduko wumuvuduko unyuze muri orifice ya Calibrated) cyangwa ubwiza bwa polymer uvanze mumashanyarazi akwiye.Iheruka ni igipimo cy'uburebure bwa polymer buzwi nka Intrinsic viscosity cyangwa IV kandi agaciro ka fibre isanzwe ya fibre ni 0,6 dl / g muri 60/40 w / w ivanze na fenol na tetrachloroethane solvent.IV mubisubizo byanyuma bifitanye isano na Mv (uburemere bwa Viscosity ugereranije uburemere bwa molekuline) ya polymer hamwe na Mark Howink ingero (Ikigereranyo 1).