Kev tuav dej yog ib qho cuab yeej tseem ceeb rau ntau lub lag luam uas siv cov tshuaj hydrophilic xws li cellulose ethers.Hydroxypropylmethylcellulose (HPMC) yog ib qho ntawm cov cellulose ethers nrog cov dej khaws cia siab.HPMC yog ib tug semi-synthetic polymer muab los ntawm cellulose thiab feem ntau yog siv nyob rau hauv ntau yam kev siv nyob rau hauv kev tsim kho, tshuaj thiab zaub mov industries.
HPMC yog dav siv los ua cov thickener, stabilizer thiab emulsifier nyob rau hauv ntau yam khoom noj xws li ice cream, sauces thiab hnav khaub ncaws los txhim kho lawv kev ntxhib los mos, sib xws thiab txee lub neej.HPMC kuj tseem siv rau hauv kev tsim cov tshuaj hauv kev lag luam kws tshuaj raws li kev sib khi, disintegrant thiab zaj duab xis txheej.Nws kuj yog siv los ua cov dej tuav hauv cov khoom siv hauv tsev, feem ntau hauv cov cement thiab mortar.
Kev tuav dej yog ib qho cuab yeej tseem ceeb hauv kev tsim kho vim tias nws pab kom cov cement thiab mortar tshiab tsis qhuav tawm.Kev ziab tuaj yeem ua rau shrinkage thiab tawg, ua rau cov qauv tsis muaj zog thiab tsis ruaj khov.HPMC pab tswj cov dej hauv cov cement thiab mortar los ntawm absorbing dej molecules thiab maj mam tso lawv raws sij hawm, cia cov ntaub ntawv tsim kho kom zoo thiab tawv.
Lub hauv paus ntsiab lus ntawm kev tuav dej ntawm HPMC yog ua raws li nws cov hydrophilicity.Vim tias muaj cov pab pawg hydroxyl (-OH) hauv nws cov qauv molecular, HPMC muaj kev sib raug zoo rau cov dej.Cov pab pawg hydroxyl cuam tshuam nrog cov dej molecules los tsim hydrogen bonds, uas ua rau tsim cov hydration plhaub nyob ib ncig ntawm lub polymer chains.Lub plhaub hydrated tso cai rau cov saw hlau polymer kom nthuav dav, nce qhov ntim ntawm HPMC.
Kev o ntawm HPMC yog cov txheej txheem dynamic uas nyob ntawm ntau yam xws li qib kev hloov pauv (DS), qhov loj me, qhov kub thiab pH.Qib ntawm kev hloov pauv yog hais txog cov lej hloov pauv hydroxyl pawg ib chav tsev anhydroglucose hauv cov saw cellulose.Qhov siab dua tus nqi DS, qhov siab dua qhov hydrophilicity thiab qhov zoo dua qhov kev tuav dej.Qhov loj me me ntawm HPMC kuj cuam tshuam rau kev tuav dej, vim tias cov khoom me me muaj qhov loj dua ntawm thaj tsam ntawm ib chav tsev, ua rau muaj kev nqus dej ntau dua.Kub thiab pH tus nqi cuam tshuam rau qib ntawm o thiab dej tuav, thiab kub dua thiab qis pH tus nqi txhim kho qhov o thiab dej tuav cov khoom ntawm HPMC.
Lub tshuab khaws dej ntawm HPMC suav nrog ob txheej txheem: nqus thiab desorption.Thaum nqus tau, HPMC absorbs dej molecules los ntawm ib puag ncig ib puag ncig, tsim lub plhaub hydration nyob ib ncig ntawm cov saw hlau polymer.Lub plhaub hydration tiv thaiv cov saw hlau polymer los ntawm kev sib tsoo thiab ua rau lawv sib cais, ua rau o ntawm HPMC.Cov dej nqus dej molecules tsim hydrogen bonds nrog hydroxyl pawg hauv HPMC, txhim kho cov dej tuav dej.
Thaum lub sij hawm desorption, HPMC maj mam tso cov dej molecules, cia cov khoom siv hauv tsev kho kom zoo.Kev tso tawm qeeb ntawm cov dej molecules kom ntseeg tau tias cov cement thiab mortar nyob twj ywm tag nrho hydrated, ua rau cov qauv ruaj khov thiab ruaj khov.Kev tso tawm qeeb ntawm cov dej molecules tseem muab cov dej tsis tu ncua rau cov cement thiab mortar, txhim kho cov txheej txheem kho thiab ua kom lub zog thiab ruaj khov ntawm cov khoom kawg.
Hauv cov ntsiab lus, kev tuav dej yog ib qho cuab yeej tseem ceeb rau ntau lub lag luam uas siv cov tshuaj hydrophilic xws li cellulose ethers.HPMC yog ib qho ntawm cov cellulose ethers uas muaj cov dej tuav tau zoo thiab tau siv dav hauv kev tsim kho, tshuaj thiab zaub mov kev lag luam.Cov dej tuav cov khoom ntawm HPMC yog raws li nws cov hydrophilicity, uas ua rau nws nqus dej molecules los ntawm ib puag ncig ib puag ncig, tsim lub plhaub hydration nyob ib ncig ntawm cov saw hlau polymer.Lub plhaub hydrated ua rau HPMC o, thiab qhov tso tawm qeeb ntawm cov dej molecules kom ntseeg tau tias cov khoom siv hauv tsev tseem muaj dej txaus, ua rau cov qauv ruaj khov thiab ruaj khov.
Post lub sij hawm: Aug-24-2023