Strain-induced crystallization ntawm PTMEG mos ntu, qhov tseeb difunctionality thiab qis acidity yog tag nrho cov pab cuam rau lub superior mechanical zog ntawm cov txuam polyurethane elastomers. Cov xwm txheej no ua rau PTMEG cov khoom xaiv rau cov txheej txheem tshwj xeeb hauv cov log, siv, log tsheb, tubing, qhov chaw tsis zoo, thiab ntau lwm yam khoom.
Piv nrog polyester-hom polyurethanes, PPG-polyether polyols kuj pom zoo hydrolysis tsis kam thiab kub tsis tshua muaj zog. Txawm li cas los xij, thaum muab piv nrog PTMEG thiab polyester polyols, PPG polyols muaj cov khoom siv tsis zoo thiab muaj ntau dua rau cov thermo-oxidative degradation.
Hauv kev sib piv rau PPG polyols, polyester polyols muaj cov khoom siv zoo dua qub, xws li tensile thiab kua muag lub zog thiab flex qaug zog. Polyester polyols yog cov khoom siv tshuaj tiv thaiv ntawm dicarboxylic acids thiab diols, thiab cov ntu polyester tuaj yeem ua crystalline lossis amorphous. Cov polyesters no tiv taus cov roj, roj, cov kuab tshuaj, thiab oxidation.
Cov polycaprolactone polyols pom cov viscosities qis dua, qhov nqaim molecular hnyav faib, thiab cov kua qaub qis uas txhim kho lawv cov hydrolytic stability. Cov polycarbonate polyols yog tus cwj pwm los ntawm cov cua sov thiab noo noo tsis kam tiv thaiv polyester polyols.
Kev ua tau zoo nrog Corresponding Urethane Elastomers
Polyether thiab polyester polyols kuj muaj ntau yam kev ua tau zoo ntawm cov yam ntxwv tshwj xeeb ntawm polyurethanes, xws li hydrolytic stability, tshuaj tiv thaiv, thiab lwm yam.
Hydrolytic stability
Polyether-raws li polyurethanes muaj kev tiv thaiv zoo heev rau hydrolysis, txawm tias kub dua. Cov polyurethanes no yog cov khoom siv zoo tshaj plaws rau cov ntawv thov uas cuam tshuam rau hauv dej lossis cov ntawv thov uas xav tau cov cuab yeej zoo khaws cia hauv qhov chaw sov thiab ntub.
Thaum polyesters muab siab dua pib tensile thiab kua muag tsis kam, lawv muaj kev cuam tshuam rau hydrolytic cleavage. Tsis tas li ntawd, lub xub ntiag ntawm residual esterification catalysts tuaj yeem ua kom cov hydrolysis.
Polycaprolactone polyols thiab polycarbonate polyols muaj hydrolytically ruaj khov dua li tus qauv adipate thiab phthalate polyesters, vim lawv cov qib acid qis thiab qis qis los tsim cov kua qaub moieties thaum hydrolysis.
Tshuaj tiv thaiv
Polyester-raws li polyurethanes, tshwj xeeb tshaj yog cov semi-crystalline polyol-raws li polyurethanes, muaj ntau resistant rau tej yam tshuaj. Polyester-based polyurethanes yuav pab koj cov khoom tiv thaiv cov roj, roj, thiab cov kuab tshuaj hydrocarbon.
Yog hais tias tsis kam mus ya raws thiab me ntsis acids thiab bases yog ib qho tseem ceeb, polyether-based polyurethanes yog ib qho kev xaiv zoo heev rau koj daim ntawv thov.
Tsawg kub thiab Thermal Performance
Polyethers muaj qis dua iav hloov pauv kub (Tg) thiab zoo khaws lawv qhov yooj yim thiab cuam tshuam rau qhov kub thiab txias. Polyesters, lub sijhawm no, pom zoo dua thermo-oxidative stability thiab cov khoom tuav ntawm qhov kub siab.