Dej ceev yog ib qho khoom tseem ceeb rau ntau qhov kev lag luam uas siv cov tshuaj hydrophilic xws li cov kws kho cellulose. Hydroxypropylencellulose (HPMC) yog ib qho ntawm cov cellulose cov neeg muaj kev nyab xeeb nrog dej siab khaws cov khoom. HPMC yog qhov hluav taws xob semi-hluav taws xob muab tau los ntawm cellulose thiab feem ntau siv nyob rau ntau cov ntawv thov hauv kev siv hauv kev tsim kho, chaw muag tshuaj thiab khoom noj khoom haus.
HPMC tau dav siv los ua tuab, stabilizer thiab emulsifier hauv ntau yam zaub mov noj, cov kua nplaum thiab kev hnav khaub ncaws kom txhim kho lawv lub neej thiab txee. HPMC kuj tseem siv rau hauv kev tsim cov kws tshuaj paus hauv kev lag luam kws tshuaj li cov phau ntawv qhia txog, xiam oob qhab thiab ua yeeb yam tus neeg sawv cev. Nws kuj tseem siv los ua cov dej-tuav cov neeg sawv cev hauv cov ntaub ntawv tsim tsev, feem ntau yog nyob rau xis mas thiab tshuaj khib.
Dej ceev yog ib qho khoom tseem ceeb hauv kev tsim kho vim tias nws pab ua kom freshly sib xyaw ua ke xis mas thiab tshuaj khib tawm ntawm ziab. Kev ziab khaub ncaws tuaj yeem ua rau shrinkage thiab tawg, ua rau muaj zog thiab tsis ruaj khov qauv. HPMC pab kom cov ntsiab lus hauv dej hauv cov cement thiab txoj kev khib nyiab los ntawm kev nqus dej molecules thiab maj mam tso lawv lub sijhawm, tso cai rau cov ntaub ntawv kom raug thiab tawv.
Dej tuav dej ceev ceev ntawm HPMC yog nyob ntawm nws hydrophilicity. Vim muaj cov pab pawg hydroxyl (-h) nyob rau hauv nws cov qauv molecular, HPMC muaj kev sib raug zoo rau dej. Cov pab pawg hydroxyl sib cuam tshuam nrog cov dej lwg roj los ua cov hydrogen bonds, uas ua rau tsim ntawm lub plhaub mis las ncig lub ntsej muag polymer. Lub plhaub hydrated tso cai rau cov ntaub pua npab ua kom nthuav dav, nce qhov ntim ntawm HPMC.
O ntawm HPMC yog cov txheej txheem kev sib txawv uas nyob ntawm ntau yam xws li qib degree (ds), ntsuas kub thiab ph. Cov degree ntawm kev hloov pauv yog hais txog tus naj npawb ntawm cov pab pawg hydroxyl ib pawg ntawm cov xov xwm cellule. Qhov siab dua DS tus nqi, ntau dua cov hydrophilicity thiab qhov zoo dua cov dej khaws cia. Lub particle loj ntawm HPMC kuj cuam tshuam rau kev txuag dej, raws li cov dej me muaj qhov chaw ntau dua ib qho kev nqus dej ntau ntxiv. Qhov kub thiab tus nqi cuam tshuam rau kev kawm txog qhov kub thiab dej ua haujlwm, thiab ntau dua PH tus nqi txhim kho cov khoom ntawm HPMC.
Cov dej ua kom rov ua haujlwm ntawm HPMC koom nrog ob qho txheej txheem: kev nqus thiab desorption. Thaum nqus tau, HPMC cov dej nqus dej lwg me me los ntawm ib puag ncig ib puag ncig, sib sau cov plhaub ib puag ncig hydration nyob ib ncig ntawm cov saw polymer. Cov quav dej plhaub tiv thaiv cov saw polymer los ntawm kev sib tsoo thiab ua rau lawv sib cais, coj mus rau o ntawm HPMC. Kev nqus dej Molecules tsim cov pawg hydrogen nrog cov pawg hydroxyl hauv Hydroxyl pawg hauv Hydrox, txhim kho cov dej khaws cia ua tau zoo.
Thaum lub sij hawm destorption, HPMC maj mam tso cov lwg roj, tso cai rau cov khoom tsim kho kom raug. Kev tso dej qeeb ntawm cov lwg dej kom ntseeg tau tias cov cement thiab tshuaj khib tas li hau, ua rau muaj cov qauv ruaj khov thiab ruaj khov. Kev tso dej qeeb ntawm cov lwg me me tseem muab cov dej tsis sib tov thiab tshuaj khib nyiab, txhim kho lub zog kho thiab ua kom muaj zog thiab ruaj khov ntawm cov khoom kawg.
Hauv cov ntsiab lus, cov dej tuav yog qhov khoom tseem ceeb rau ntau qhov kev lag luam uas siv cov tshuaj hydrophilic xws li cov kws kho cellulose. HPMC yog ib qho ntawm cov cellulose cov neeg muaj kev pab nrog dej siab khaws cov khoom siv thiab yog siv dav siv hauv kev tsim kho, chaw muag tshuaj thiab khoom noj khoom haus. Cov khoom siv dej ceev ceev ntawm HPMC yog nyob ntawm nws hydrophilicity, uas ua rau nqus dej lwg dej los ntawm ib puag ncig hydration nyob ib ncig ntawm cov saw polymer. Lub plhaub hydrated ua rau HPMC mus rau o, thiab qeeb tso cov roj av tseem ua kom lub tsev tseem ua kom cov khoom ruaj khov, ua rau muaj cov qauv ruaj khov thiab ruaj khov.
Lub Sijhawm Post: Lub Yim Hli 24-2023