HydroxyPropyyl methylcellose (HPMC) yog cov dej-soluble polymer nquag siv hauv kev lag luam, tshuaj thiab khoom noj. Ib qho ntawm cov haujlwm tseem ceeb ntawm HPMC nyob rau hauv cov khoom sib txawv yog los kho viscosity, uas yog tiav los ntawm nws cov qauv molecular thiab kev sib cuam tshuam nrog cov kuab tshuaj (feem ntau yog dej).
1. Molecular qauv ntawm HPMC thiab nws cov nyhuv ntawm viscosity
HPMC muaj ib lub cellulose caj qaum nrog metoxy thiab hydroxypropyl chaw. Nws cov saw cellulose nqa tau ntau cov pawg hydroxyl (-oh), uas tuaj yeem tsim cov lwg roj hmab, yog li txhim kho cov viscosity ntawm kev daws. Lub hydroxypropyl thiab methoxy hloov chaw nyob rau hauv HPMC molecule kuj cuam tshuam rau nws affinity thiab solubility nrog dej. Hauv dej, HPMC molecular chart tuaj yeem nthuav tawm thiab nqus tau ntau cov dej loj, yog li nce lub viscosity ntawm kev daws.
Ntau hom HPMC sib txawv yuav qhia cov yam ntxwv viscosity txawv vim lawv cov metub degrees ntawm metoxy thiab hydroxypropny hloov chaw. Feem ntau hais lus, HPMC nrog qib siab dua ntawm hydroxyprops hloov cov ntsiab lus muaj zog-nce li methoxy cov ntsiab lus txawv nyob rau hauv kev sib txawv thiab kub rhiab. Yog li ntawd, cov qauv molecular ntawm HPMC muaj qhov cuam tshuam ncaj qha rau nws cov viscosity-nce cov nyhuv.
2. Kev qhia txog cov yam ntxwv thiab viscosity ntawm HPMC
HPMC muaj cov dej ua kom zoo, uas ua rau nws nce ntxiv viscosity hauv cov kev daws teeb meem aqueous. Hauv dej, cov molecular chains ntawm hpmc nqus dej thiab tsim cov qauv network txuas ntxiv, ua rau muaj kev txo qis ntawm cov tshuaj thiab kev nce qib hauv viscosposity. Txheej txheem sib cais no yog cov kauj ruam ib qib zuj zus, thiab qhov kub thiab kub thiab ua haujlwm rau nws. Feem ntau, HPMC yws sai ntawm tsawg kub, tab sis nws viscosity nce nrog nce kub. Yog li ntawd, siab dua qhov kev sib cais kub nyob rau hauv qee yam, ntau dua cov viscosity ntawm kev daws.
Lub solubility ntawm HPMC kuj muaj feem xyuam rau tus nqi ntawm tus nqi nruab nrab. Nyob rau hauv nruab nrab rau cov tsis muaj zog alkaline ntau, hpmc dissolves zoo dua thiab nce viscosity; Thaum nyob hauv cov muaj zog acidic lossis alkaline cov xwm txheej, cov solubility thiab viscosity ntawm HPMC yog inhibited. Yog li ntawd, nyob rau hauv cov khoom sib txawv, lub viscosity hloov muaj peev xwm ntawm HPMC kuj yuav tsum xav txog PHEEJ PHEEJ PHEEJ TXOG LUB CEV.
3. Cov nyhuv ntawm HPMC concentration ntawm viscosity
Cov concentration ntawm HPMC yog ib qho tseem ceeb yam cuam tshuam rau viscosity. Raws li cov concmration ntawm HPMC nce, cov molecular saw network tsim nyob rau hauv kev daws teeb meem ua denser thiab viscosity nce siab. Ntawm cov kev sib txuam qis, kev sib cuam tshuam ntawm HPMC molecular chains tsis muaj zog, thiab lub viscosity ntawm kev daws teeb meem. Txawm li cas los xij, thaum lub HPMC concentration ncav ib theem, kev sib txuas ntawm kev sib tw ntawm cov molecular yuav ua rau viscosity los ua kom muaj exponentially.
Kev sim qhia tias thaum lub siab HPMC nyob hauv qee qhov ntau, nws viscosity nce nyob rau hauv ncaj qha rau cov siab. However, when the concentration is too high, the rheological properties of the solution will change, showing pseudoplasticity or thixotropy, and the viscosity decreases with the increase of shear rate. Yog li ntawd, hauv cov ntawv thov siv, tus nqi HPMC ntxiv kom tau tswj hwm raws li qhov xav tau kom ua tiav cov viscosity zoo tagnrho.
4. Cov nyhuv ntawm molecular hnyav ntawm viscosity
Qhov hnyav molecular ntawm HPMC kuj tseem yog qhov tseem ceeb hauv kev txiav txim siab nws viscosity. Feem ntau, qhov loj dua cov molecular qhov hnyav ntawm HPMC, ntau dua cov viscosity ntawm nws txoj kev daws teeb meem. Qhov no yog vim HPMC nrog lub cev loj molecular hnyav tuaj yeem tsim cov qauv molecular thiab ntau dua cov kev sib koom ua ke ntawm cov tshuaj thiab nce viscosity. Yog li ntawd, HPMC nrog cov hnyav molecular sib txawv tuaj yeem siv los kho cov viscosity xav tau cov khoom sib txawv ntawm cov khoom sib txawv.
Hauv qee cov ntawv thov, xaiv qhov hnyav dua molecular hnyav HPMC tuaj yeem txhim kho kev sib xws ntawm cov khoom lag luam, xws li cov ntaub ntawv tuab hauv cov ntaub ntawv hauv tsev; Thaum nyob hauv lwm cov ntawv thov, xws li lub chaw muag tshuaj, qhov hnyav molecular hnyav HPMC yuav tau raug xaiv kom hloov cov tshuaj tso tawm lossis txhim kho qhov saj.
5. Cov nyhuv ntawm cov viscosity ntawm HPMC daws
Lub viscosity ntawm HPMC hloov pauv tau yooj yim nrog kub. Feem ntau hais lus, lub viscosity ntawm HPMC kev daws teeb meem tsawg dua ntawm cov kub siab dua. Qhov no yog vim tias qhov kub kub rhuav tshem cov hydrogen bonds ntawm HPMC lwg me me thiab txo qis cov molecular charets, yog li txo lub viscosity ntawm kev daws. Txawm li cas los xij, hauv qee kis tshwj xeeb, cov neeg viscosity ntawm HPMC tuaj yeem nce nyob rau hauv ib qho kub thiab qhov uas muaj kev cuam tshuam nrog nws cov qauv molecular thiab kev daws teeb meem.
Ntawm tsawg kub, lub viscosity ntawm HPMC kev daws teeb meem yog qhov siab thiab kev txav ntawm cov molecular chains yog txwv. Cov cuab yeej no ua rau nws ua tau zoo hauv cov ntawv thov uas cov khoom ntawm cov khoom lag luam tsis tshua muaj zog yuav tsum tau nce.
6. Cov nyhuv ntawm shear tus nqi ntawm lub viscosity ntawm hpmc
HPMC cov kev daws teeb meem feem ntau yog nthuav tawm shear cov yam ntxwv, uas yog, lub viscosity txo nrog nce shear tus nqi. Ntawm cov qauv qis qis, tus qauv network ntawm HPMC molecular saw yog qhov ua tiav, uas yog li nthuav tawm viscosity. Txawm li cas los xij, ntawm High Shear cov nqi, lub entanglement thiab hla kev sib txuas ntawm cov pob zeb molecular puas tsuaj, thiab viscosity txo. Cov cuab yeej no tau siv dav hauv kev lag luam xws li cov ntaub ntawv tsim tsev, xim thiab tuaj yeem txhim kho qhov kev ua haujlwm ntawm cov khoom lag luam.
7. Cov nyhuv ntawm cov khoom ntxiv sab nraud
Nyob rau hauv ntau daim ntawv thov, HPMC feem ntau siv ua ke nrog lwm cov kev sib ntxiv. Ntau hom kev sib ntxiv, xws li salts, surfactants thiab lwm cov polymers, yuav cuam tshuam rau kev viscrosity ntawm HPMC. Piv txwv li, qee cov ntsev ntxiv tuaj yeem txo qhov viscosity ntawm HPMC cov kev daws teeb meem ntawm HPMC molecular charets thiab rhuav tshem cov hydrogen bisting network tsim. Qee cov thickeners tuaj yeem ua haujlwm Synergistically nrog HPMC kom nce cov viscosity ntawm kev daws teeb meem.
Raws li cov tuab tuab siv tuab, HPMC cov nyhuv ntawm cov qauv viscosity yog tsuas yog ua tiav los ntawm kev sib xyaw ua ke, thiab sab nraud yam ntxwv xws li kub, shear tus nqi thiab ntxiv. Los ntawm kev tsim kho cov tsis sib haum ntawm HPMC, kho kom haum ntawm cov khoom lag luam viscosity tuaj yeem ua tiav kom tau raws li cov kev xav tau ntawm cov ntawv thov sib txawv.
Lub Sijhawm Post: Feb-17-2025