Dab tsi yogVim Li Cas Rau Qhov Sib Txawvether tpu thiab ester tpu?
1. Polyether Polyols
Polyether Polyols yog polymers lossis oligomers nrog ether cov ntawv hauv lub ntsiab molecular saw ntawm lub terminals. Vim tias ERETHET BRABTS hauv lawv cov qauv muaj cov khoom sib zog qis, cov khoom yooj yim dua, cov khoom siv polyurethane tau npaj los ntawm lawv muaj qhov qis qis - cov dej khov kho kub thiab zoo nkauj heev. Txawm hais tias lawv cov khoom siv tshuab tsis zoo li cov polyester polyol - raws polyurethane, lawv muaj kev xav zoo dua. Lub kaw lus muaj qhov yooj yim ua tiav nrog isocyanates thiab ntxiv, thiab muaj cov khoom ua tau zoo heev.
2. Polyester Polyols
Polyester Polyols yog tsim los ntawm cov kev cuam tshuam hws ntawm dicarboxylic acids thiab dej cawv nrog ob lossis ntau pawg hydroxyl. Lawv cov qauv kev teeb tsa suav nrog cov pab pawg Es ester hauv cov pawg mole thiab hydroxyl pawg ntawm cov terminals, nrog molecular hnyav feem pua feem ntau muaj 3000.
Polyurethane cov ntaub ntawv raws li Polyester Polyols feem ntau muaj cov khoom siv zoo, cov roj ua tsis tau zoo, thiab cov kev coj zoo tshaj plaws, thiab kev hnav zoo tshaj plaws. Txawm li cas los xij, lawv muaj cov neeg txom nyem hydrolysis tsis zoo thiab tsawg - qhov ntsuas kub. Qhov kev xav ntawm lawv cov khoom, tshwj xeeb tshaj yog thaum kub tsawg, tsis yog li muag li ntawm polyether polyol - raws polyurethane. Polyester Polyols muaj lub zog cohesive loj thiab yog cov khib nyiab feem ntau ntawm chav sov. Lawv viscosity tom qab cov cua sov thiab melting yog qhov tseem ceeb, thiab lawv cov khoom ua haujlwm nrog lwm cov ntaub ntawv raw hauv polyurethane synthesis nyob deb dua rau cov polyether polyols.
3. Kev hloov pauv ntu ntu
Thaum cov tshuaj sib piv ntawm cov ntaub ntawv raw yog tas li, hloov qhov ntev ntawm cov saw ntu sib txawv ntawm cov khoom ntawm elastomers nrog cov ntu sib txawv. Nce cov molecular hnyav ntawm cov mos mos ntu txhais tau tias txo cov feem ntawm kev sib cais ntawm cov ntu nyuaj. Vim tias Ehether Bonds muaj cov hluav taws xob qis dua thiab cov qhab nia me - kev sib hloov cov teeb meem, raws li cov saw hlau loj ntxiv. Nrog rau kev nce qib ntawm cov ntu mos, lub zog txo qis, cov elasticity nce ntxiv, thiab kev tawm tsis muaj kev cuam tshuam ntev. Rau polyester diols, cov nyhuv ntawm cov mos mos ntu ntev yog tsis pom tseeb heev. Qhov no yog vim tias muaj cov pab pawg ester ester ntawm cov molecules tau hais tias raws li cov pab pawg ua haujlwm tsis zoo, txo cov pab pawg ua kom tsis zoo, txo cov ntu ntawm lub zog. Tsis tas li ntawd, cov hydrolysis ua rau ntawm polyester - hom polyurethane txo qis dua li nce qib polyester. Hauv kev sib piv, cov hydrolysis ua tsis taus ntawm polyether - hom polyurethane nce nrog nce saws saw segment ntev.