Hom polymer yog HPMC li cas?

HPMC, los yog hydroxypropyl methylcellulose, yog ib hom cellulose-based polymer uas tau siv dav hauv kev lag luam tshuaj, zaub mov, thiab kev tu tus kheej. Cellulose yog ib tug natural polymer uas muaj nyob rau hauv cov nroj tsuag thiab yog ib tug ntau tshaj plaws organic compound nyob rau hauv lub ntiaj teb no. Nws yog linear polymer ua los ntawm cov piam thaj monomers uas txuas los ntawm β (1 → 4) glycosidic bonds.

HPMC yog tsim los ntawm kev hloov kho cellulose nrog methyl lossis hydroxypropyl pawg. Cov kev hloov kho no tuaj yeem ua los ntawm kev ua haujlwm ntawm cellulose nrog cov reagents tsim nyog nyob rau hauv muaj cov kua qaub catalyst. Cov tshuaj tiv thaiv ntawm cellulose thiab methyl chloride los yog methyl bromide yields methylcellulose, thaum cov tshuaj tiv thaiv ntawm cellulose thiab propylene oxide yields hydroxypropyl cellulose. HPMC yog tsim los ntawm kev sib txuas ob qhov kev cuam tshuam los qhia ob pawg methyl thiab hydroxypropyl mus rau cov pob txha cellulose.

Qhov tshwm sim polymer muaj ib tug complex qauv uas yuav txawv nyob ntawm seb lub degree ntawm hloov (DS) ntawm methyl thiab hydroxypropyl pawg. DS yog hais txog tus naj npawb nruab nrab ntawm cov pab pawg hydroxyl hloov hauv ib chav tsev anhydroglucose hauv cov pob txha cellulose. Feem ntau, HPMC muaj DS ntawm 1.2 txog 2.5 rau pawg methyl thiab 0.1 txog 0.3 rau pawg hydroxypropyl. Cov qauv ntawm HPMC yog qhov nyuaj ntxiv los ntawm qhov tseeb tias pawg methyl thiab hydroxypropyl tuaj yeem muab faib ua ntu zus raws cov pob txha cellulose, uas ua rau muaj ntau yam polymer nrog ntau yam khoom.

HPMC yog cov dej-soluble polymer uas tsim cov khoom zoo li gel thaum nws hydrated. Cov khoom gelation ntawm HPMC nyob ntawm ntau yam, suav nrog DS, qhov hnyav molecular, thiab cov concentration ntawm cov polymer. Feem ntau, HPMC tsim cov gel ruaj khov ntawm ntau dua thiab nrog cov txiaj ntsig DS siab dua. Tsis tas li ntawd, cov khoom gelation ntawm HPMC tuaj yeem cuam tshuam los ntawm pH, ionic zog, thiab kub ntawm cov tshuaj.

Cov khoom tshwj xeeb ntawm HPMC ua rau nws muaj txiaj ntsig zoo hauv ntau daim ntawv thov. Hauv kev lag luam kws tshuaj, HPMC yog siv los ua ib qho kev sib khi, disintegrant, thiab zaj duab xis-ua tus neeg sawv cev hauv cov ntsiav tshuaj thiab tshuaj ntsiav. Nws kuj tuaj yeem siv los hloov kho tus nqi tso tawm ntawm cov tshuaj los ntawm daim ntawv ntau npaum. Hauv kev lag luam zaub mov, HPMC yog siv los ua cov thickener, stabilizer, thiab emulsifier. Nws yog feem ntau siv rau hauv cov khoom noj muaj roj tsawg lossis txo cov calories kom ua raws li kev ntxhib los mos thiab lub qhov ncauj ntawm cov khoom noj muaj roj ntau dua. Hauv kev lag luam saib xyuas tus kheej, HPMC yog siv los ua cov thickener, zaj duab xis-tsim tus neeg sawv cev, thiab emulsifier hauv tshuaj zawv plaub hau, tshuaj pleev, thiab lwm yam khoom.

Hauv kev xaus, HPMC yog cellulose-raws li polymer uas yog tsim los ntawm chemically modifying cellulose nrog methyl thiab hydroxypropyl pawg. Qhov tshwm sim polymer yog dej-soluble thiab muaj ib tug complex qauv uas muaj peev xwm sib txawv nyob ntawm seb lub degree ntawm kev hloov thiab kev faib ntawm methyl thiab hydroxypropyl pawg. HPMC yog ntau yam polymer uas muaj ntau yam kev siv hauv kev lag luam tshuaj, zaub mov, thiab kev saib xyuas tus kheej.