qhia
Cellulose ethers yog cov polymers anionic uas yaj tau hauv dej los ntawm cellulose. Cov polymers no muaj ntau daim ntawv thov hauv ntau yam lag luam xws li khoom noj, tshuaj, tshuaj pleev ib ce, thiab kev tsim kho vim lawv cov khoom xws li thickening, gelling, zaj duab xis-tsim, thiab emulsifying. Ib qho ntawm cov khoom tseem ceeb tshaj plaws ntawm cellulose ethers yog lawv qhov kub thermal gelation (Tg), qhov kub uas cov polymer dhau los ntawm kev hloov pauv theem ntawm sol mus rau gel. Cov khoom no yog qhov tseem ceeb hauv kev txiav txim siab qhov kev ua tau zoo ntawm cellulose ethers hauv ntau yam kev siv. Hauv tsab xov xwm no, peb tham txog qhov kub thermal gelation ntawm hydroxypropyl methylcellulose (HPMC), ib qho ntawm cov cellulose ethers siv ntau tshaj plaws hauv kev lag luam.
Kub ntawm HPMC hauv thermal gelation
HPMC yog ib qho semi-synthetic cellulose ether siv dav hauv ntau yam kev siv vim nws cov khoom tshwj xeeb. HPMC yaj tau zoo heev hauv dej, tsim cov tshuaj viscous meej ntawm qhov concentration qis. Ntawm qhov concentration siab dua, HPMC tsim cov gels uas rov qab tau thaum cua sov thiab txias. Thermal gelation ntawm HPMC yog ob kauj ruam txheej txheem uas cuam tshuam nrog kev tsim cov micelles ua raws li kev sib sau ua ke ntawm micelles los tsim lub network gel (Daim Duab 1).
Qhov kub ntawm cov tshuaj HPMC nyob ntawm ntau yam xws li qib kev hloov pauv (DS), qhov hnyav molecular, qhov concentration, thiab pH ntawm cov tshuaj. Feem ntau, qhov siab dua DS thiab qhov hnyav molecular ntawm HPMC, qhov siab dua qhov kub ntawm cov tshuaj thermal gelation. Qhov concentration ntawm HPMC hauv cov tshuaj kuj cuam tshuam rau Tg, qhov siab dua qhov concentration, qhov siab dua Tg. Qhov pH ntawm cov tshuaj kuj cuam tshuam rau Tg, nrog rau cov tshuaj acidic ua rau Tg qis dua.
Kev ua kom sov ntawm HPMC gelation yog thim rov qab thiab tuaj yeem cuam tshuam los ntawm ntau yam sab nraud xws li lub zog shear, kub, thiab ntsev concentration. Shear rhuav tshem cov qauv gel thiab txo qis Tg, thaum nce qhov kub ua rau gel yaj thiab txo qis Tg. Ntxiv ntsev rau hauv cov tshuaj kuj cuam tshuam rau Tg, thiab qhov muaj cov cations xws li calcium thiab magnesium ua rau Tg nce.
Daim ntawv thov ntawm Tg HPMC sib txawv
Tus cwj pwm thermogelling ntawm HPMC tuaj yeem tsim kho rau ntau yam kev siv. Cov HPMCs Tg qis yog siv rau hauv cov ntawv thov uas xav tau kev gelation sai, xws li cov khoom qab zib tam sim ntawd, kua ntses thiab kua zaub. HPMC nrog Tg siab yog siv rau hauv cov ntawv thov uas xav tau kev gelation qeeb lossis ntev, xws li kev tsim cov tshuaj xa mus, cov ntsiav tshuaj tso tawm tas mus li, thiab cov ntaub qhwv qhov txhab.
Hauv kev lag luam khoom noj, HPMC siv ua cov khoom ua kom tuab, ruaj khov thiab gelling agent. Low Tg HPMC siv rau hauv cov khoom qab zib uas xav tau gelation sai kom muab cov qauv thiab qhov ncauj xav tau. HPMC nrog Tg siab siv rau hauv cov khoom noj uas muaj roj tsawg uas xav tau gelation qeeb lossis ntev kom tiv thaiv kev sib xyaw thiab tswj cov qauv nthuav dav.
Hauv kev lag luam tshuaj, HPMC siv ua tus binder, disintegrant thiab sustained release agent. HPMC nrog Tg siab siv rau hauv kev tsim cov ntsiav tshuaj ncua ntev, qhov twg xav tau kev ncua sijhawm lossis ntev gelation kom tso cov tshuaj tawm rau lub sijhawm ntev. HPMC Tg qis siv rau hauv kev tsim cov ntsiav tshuaj qhov ncauj, qhov twg xav tau kev disintegration sai thiab gelation kom muab qhov ncauj xav tau thiab yooj yim nqos.
xaus lus
Qhov kub ntawm HPMC yog ib qho tseem ceeb uas txiav txim siab nws tus cwj pwm hauv ntau yam kev siv. HPMC tuaj yeem kho nws Tg los ntawm qib kev hloov pauv, qhov hnyav molecular, concentration thiab pH tus nqi ntawm cov tshuaj kom haum rau ntau yam kev siv. HPMC nrog Tg qis yog siv rau cov ntawv thov uas xav tau gelation sai, thaum HPMC nrog Tg siab yog siv rau cov ntawv thov uas xav tau gelation qeeb lossis ntev. HPMC yog ib qho cellulose ether uas siv tau ntau yam thiab siv tau ntau yam nrog ntau yam kev siv hauv ntau yam kev lag luam.
Lub sijhawm tshaj tawm: Lub Yim Hli-24-2023