Siab -Tub kub tsis kam ntawm Polyvinyl cawv
Polyvinyl cawv (PVA) yog cov khoom siv hluavtaws uas muaj qhov kub thiab txias ua haujlwm ntev li ntawm -20℃txog 120 degree. Qhov no qhia tau hais tias, nyob rau hauv ib txwm muaj xwm txheej, nws tuaj yeem tiv taus qhov kub txog li 120℃yam tsis muaj kev puas tsuaj sai lossis poob nws cov khoom tseem ceeb. Txawm li cas los xij, nws qhov tseeb thermal kuj yuav cuam tshuam los ntawm ib puag ncig yam xws li av noo, nrog rau qhov ntom thiab tuab ntawm PVA nws tus kheej. Nyob rau hauv ib puag ncig qhuav, PVA nthuav tawm cov thermal kuj siab; conversely, nyob rau hauv ib puag ncig humid, nws tsis kam mus rau tshav kub tej zaum yuav me ntsis diminished.
Qhov cuam tshuam ntawm Kub Kub ntawm Polyvinyl Cawv Viscosity
Raws li qhov kub thiab txias, qhov viscosity ntawm polyvinyl cawv daws yuav txo qis. Qhov tshwm sim no tshwm sim vim tias qhov kub siab ua kom muaj kev txav mus los ntawm PVA molecular saw ntu, yog li txo cov kev sib cuam tshuam ntawm kev nyiam. Tsis tas li ntawd, nyob rau ntawm qhov kub thiab txias, cov polymers muaj kev cuam tshuam ntau dua rau cov tshuaj tiv thaiv degradation, uas tseem ua rau txo qis hauv cov kua viscosity. Txawm hais tias qhov kub thiab txias ua rau poob qis hauv PVA lub viscosity, nyob rau hauv nws qhov kev tso cai qhov kub thiab txias, qhov kev hloov no tsis ua rau poob sai ntawm adhesiveness lossis ib qho kev hloov pauv tseem ceeb hauv nws lub cev.
Nws yog tsim nyog sau cia tias thaum lub sij hawm ntev raug rau siab - qhov kub thiab txias ib puag ncig, polyvinyl cawv yuav raug hloov ntau yam ntawm lub cev lossis tshuaj, xws li oxidation lossis hydrolysis. Cov kev hloov pauv no muaj peev xwm cuam tshuam cov khoom siv kev ua tau zoo thiab ruaj khov; Yog li ntawd, kev siv tswv yim yuav tsum muaj kev ntsuam xyuas dav dav uas siv rau hauv tus account qhov kub thiab txias, lub sijhawm raug, thiab ib puag ncig.
Yuav Ua Li Cas Xaiv Qhov Tsim Nyog Polyvinyl Cawv
Thaum xaiv polyvinyl cawv, ntxiv rau kev txiav txim siab nws qhov siab - qhov kub thiab txias, nws yog ib qho tseem ceeb uas yuav tau xaiv cov khoom uas muaj cov qib tshwj xeeb ntawm alcoholysis thiab polymerization uas ua raws li cov kev xav tau ntawm daim ntawv thov. Piv txwv li, PVA nrog rau qib ntawm alcoholysis qis dua 95% yog soluble nyob rau hauv dej ntawm chav tsev kub, whereas PVA nrog ib tug℃ntawm alcoholysis tshaj 99.5% yuav tsum tau dej kub-tshwj xeeb ntawm kub siab tshaj 95℃- kom yaj. Ntxiv mus, PVA variants nrog txawv qib ntawm polymerization yuav pom cov yam ntxwv txawv ntawm zaj duab xis- tsim muaj peev xwm, viscosity, thiab dej solubility.
Hauv cov ntsiab lus, polyvinyl cawv ua tau zoo heev -kub tsis kam thiab ruaj khov nyob rau hauv qhov kub thiab txias. Txawm hais tias qhov ntsuas kub siab tuaj yeem ua rau txo qis me ntsis hauv nws cov viscosity, raws li cov txheej txheem kev thov, qhov kev hloov pauv no tsis cuam tshuam rau cov khoom siv tag nrho. Thaum xaiv thiab siv polyvinyl cawv, ib tug yuav tsum xaiv thiab kho kom haum raws li cov kev cai tshwj xeeb thiab tej yam kev mob los xyuas kom meej tias nws ua tiav qhov kev ua tau zoo.