Polyethylene terephthalate (PET) wani nau'in polymer ne na kristal wanda ke da kyakkyawan juriya na sinadarai, narke motsi da iya jurewa. polymer ya ƙunshi raka'a masu maimaitawa kamar yadda aka nuna a cikin Hoto 1. Kowace naúrar tana da tsayin jiki na kusan 1.09 nm da nauyin kwayoyin ~ 200. Lokacin da aka samar da shi daga amsawar terephthalic acid da ethylene glycol, an rufe shi a hagu ta H- da dama ta -OH. Polymerization don haka yana tare da samar da ruwa wanda aka cire a ƙarƙashin matsanancin zafin jiki da injin. Saboda haka kasancewar ruwa a cikin narkakkar yanayin zai yi sauri ya lalata tsarin ta yadda bushewar polymer sosai kafin narkar da zaruruwa ya zama dole.

Zoben kamshi tare da gajeriyar sarkar aliphatic yana sa polymer ya zama taurin kwayoyin halitta idan aka kwatanta da sauran polymers na alphatic kamar polyolefin ko polyamide. Rashin motsi na yanki a cikin sarƙoƙi na polymer yana haifar da kwanciyar hankali mai girma. Polymer sa yadin zai sami matsakaicin adadin maimaita raka'a 100 a kowace kwayar halitta ta yadda tsayin tsayin sarkar polymer na yau da kullun ya kasance kusan 100nm tare da nauyin kwayoyin kusan 20,000. Matsayi mafi girma na polymerization yana samar da mafi girman ƙarfin zaruruwa amma narkewar danko da kwanciyar hankali na narkewa har ma da ɗanɗano kaɗan na danshi yana haifar da lalacewa ta hydrolytic. Ana yin ma'aunin matsakaicin matsayi na polymerization ko dai ta ɗanɗanon ɗanɗano (ta hanyar auna raguwar matsa lamba ta hanyar da aka daidaita) ko ɗanɗanon polymer ɗin da aka diluted a cikin kaushi mai dacewa. Ƙarshen shine ma'auni na tsayin sarkar polymer wanda aka sani da danko na ciki ko IV kuma ƙimar ƙimar ƙimar fiber na yau da kullun shine 0.6 dl/g a cikin 60/40 w/w cakuda phenol da tetrachloroethane. IV a cikin ƙawancen ƙarshen yana da alaƙa da Mv (Matsakaicin nauyin kwayoyin danko) na polymer ta ma'aunin Mark Howink (Equation 1).