Hydroxyethylcellulose (HEC) yog cov dej-soluble polymer feem ntau siv hauv kev lag luam thiab kev tshawb fawb tshawb fawb. Nws yog tsuas yog siv los ua cov thickener, zaj duab xis-tsim tus neeg sawv cev, nplaum, emulsifier thiab stabilizer.
Basic Properties ntawm HEC
HEC yog ib qho tsis-ionic dej-soluble polymer, hydroxyethylated derivative tau los ntawm cellulose los ntawm cov tshuaj tiv thaiv ethylation. Vim nws qhov xwm txheej tsis yog-ionic, tus cwj pwm ntawm HEC hauv cov tshuaj feem ntau tsis hloov pauv los ntawm pH ntawm cov tshuaj. Nyob rau hauv sib piv, ntau ionic polymers (xws li sodium polyacrylate los yog carbomers) yog rhiab heev rau pH vim hais tias lawv lub xeev them nqi hloov pauv nrog pH, cuam tshuam rau lawv solubility thiab thickening. kev ua tau zoo thiab lwm yam khoom.
Kev ua tau zoo ntawm HEC ntawm pH sib txawv
HEC feem ntau muaj kev ruaj ntseg zoo nyob rau hauv acidic thiab alkaline tej yam kev mob. Tshwj xeeb, HEC tuaj yeem tswj hwm nws cov viscosity thiab thickening zog ntawm ntau qhov chaw pH. Kev tshawb fawb qhia tau hais tias viscosity thiab thickening muaj peev xwm ntawm HEC yog qhov ruaj khov nyob rau hauv pH ntau ntawm 3 mus rau 12. Qhov no ua rau HEC hloov tau yooj yim thickener thiab stabilizer nyob rau hauv ntau daim ntawv thov kev lag luam thiab tuaj yeem siv nyob rau hauv pH sib txawv.
Txawm li cas los xij, kev ruaj ntseg ntawm HEC tuaj yeem cuam tshuam rau qhov pH huab cua (xws li pH qis dua 2 lossis siab dua 13). Raws li cov xwm txheej no, HEC's molecular chains tuaj yeem raug hydrolysis lossis degradation, ua rau txo qis hauv nws cov viscosity lossis hloov pauv hauv nws cov khoom. Yog li ntawd, kev siv HEC nyob rau hauv cov xwm txheej huab cua no yuav tsum tau saib xyuas tshwj xeeb rau nws txoj kev ruaj ntseg.
Kev xav txog kev thov
Hauv kev siv tswv yim, pH rhiab heev ntawm HEC kuj muaj feem xyuam rau lwm yam, xws li kub, ionic zog, thiab polarity ntawm cov kuab tshuaj. Hauv qee daim ntawv thov, txawm hais tias kev hloov pauv pH muaj qhov cuam tshuam me me rau HEC, lwm yam kev cuam tshuam ib puag ncig tuaj yeem ua rau muaj kev cuam tshuam rau qhov no. Piv txwv li, nyob rau hauv qhov kub thiab txias, HEC's molecular chains yuav hydrolyze sai dua, yog li muaj kev cuam tshuam ntau dua rau nws qhov kev ua tau zoo.
Tsis tas li ntawd, nyob rau hauv ib co formulations, xws li emulsions, gels thiab coatings, HEC yog feem ntau siv ua ke nrog rau lwm cov khoom xyaw (xws li surfactants, ntsev los yog acid-base regulators). Lub sijhawm no, txawm hais tias HEC tsis nkag siab rau pH nws tus kheej, cov khoom siv no tuaj yeem cuam tshuam ncaj qha rau kev ua haujlwm ntawm HEC los ntawm kev hloov pH. Piv txwv li, lub xeev tus nqi ntawm qee cov surfactants hloov pauv ntawm cov pH sib txawv, uas tuaj yeem cuam tshuam kev cuam tshuam ntawm HEC thiab surfactants, yog li hloov cov khoom rheological ntawm cov tshuaj.
HEC yog ib qho uas tsis yog-ionic polymer uas yog qhov tsis hnov tsw rau pH thiab muaj kev ua haujlwm zoo thiab ruaj khov tshaj pH ntau yam. Qhov no ua rau nws siv dav hauv ntau daim ntawv thov, tshwj xeeb tshaj yog qhov kev ua haujlwm ruaj khov ntawm cov thickeners thiab zaj duab xis qub yuav tsum tau ua. Txawm li cas los xij, nws tseem ceeb heev uas yuav tau txiav txim siab seb qhov kev ruaj ntseg thiab kev ua tau zoo ntawm HEC yuav cuam tshuam li cas hauv pH huab cua lossis thaum siv nrog lwm cov khoom xyaw pH-sensitive. Rau cov teeb meem pH rhiab heev hauv cov ntawv thov tshwj xeeb, nws raug nquahu kom ua cov kev sim thiab kev txheeb xyuas ua ntej siv tiag tiag kom ntseeg tau tias HEC tuaj yeem ua tau zoo raws li qhov xav tau.
Post lub sij hawm: Aug-19-2024