Hydroxypropyl methylcellulose (HPMC) yog ib qho nonionic cellulose ether ua los ntawm cellulose los ntawm kev hloov tshuaj. Raws li cov ntaub ntawv tseem ceeb ntawm cov dej-soluble polymer, HPMC tau siv dav hauv kev tsim kho, tshuaj, khoom noj, tshuaj pleev ib ce thiab lwm yam. Tus cwj pwm ntawm HPMC hauv dej yog qhov tseem ceeb tshwj xeeb vim tias nws txiav txim siab nws cov txiaj ntsig hauv kev daws teeb meem, suav nrog kev ua kom tuab, kev ncua, kev sib txuas thiab kev ua yeeb yaj kiab muaj peev xwm.
HPMC o mechanism hauv dej
HPMC yuav o loj heev hauv dej. Qhov o no feem ntau yog vim muaj kev sib txuas ntawm hydrogen ntawm pawg hydroxyl thiab methoxy hauv HPMC cov qauv molecular thiab dej molecules. Thaum HPMC los rau hauv kev sib cuag nrog dej, dej molecules yuav nkag mus rau ntawm cov saw ntu ntawm HPMC molecules, rhuav tshem cov hydrogen bonds ntawm cov molecules, ncab cov ntu ntu thiab ua kom lub ntim molecular. Cov txheej txheem no yog qhov peb hu ua "o" tshwm sim.
Tshwj xeeb tshaj yog, thaum HPMC swells hauv dej, nws thawj zaug nqus dej thiab pib o, thiab tom qab ntawd maj mam tsim cov kua nplaum colloidal. Cov txheej txheem no suav nrog ob theem tseem ceeb: ib qho yog theem pib o sai sai, thiab lwm qhov yog theem tom qab qeeb qeeb. Nyob rau hauv thawj theem, HPMC nqus dej los tsim o hydrates, txheej txheem uas feem ntau ua tiav li ntawm ob peb feeb. Hauv theem no, cov dej molecules sai nkag mus rau hauv HPMC hais, ua rau lawv lub ntim nthuav dav. Raws li cov dej nkag mus ntxiv, HPMC cov molecules maj mam sib cais los ntawm cov khoom siv thiab nkag mus rau hauv cov tshuaj los tsim cov kua dej sib xws.
Cov yam ntxwv cuam tshuam qhov o ntawm HPMC hauv dej
Kub: Kub muaj qhov cuam tshuam loj rau tus cwj pwm o ntawm HPMC hauv dej. Feem ntau hais lus, raws li qhov kub thiab txias nce, qhov kev sib cais ntawm HPMC nrawm dua thiab qib ntawm qhov o yog pom tseeb dua. Qhov no yog vim hais tias lub zog kinetic ntawm cov dej molecules nce ntawm qhov kub thiab txias, ua kom yooj yim nkag mus rau ntawm ntu ntawm HPMC molecules thiab txhawb nqa lawv qhov nthuav dav. Txawm li cas los xij, qhov kub thiab txias heev yuav ua rau ib nrab degradation ntawm HPMC thiab cuam tshuam rau nws cov yam ntxwv solubility.
Qib viscosity: HPMC muaj ntau yam viscosity qib. Qhov siab dua qhov viscosity ntawm HPMC, qhov viscous ntau dua cov tshuaj colloidal tsim thaum nws swells hauv dej. Thaum HPMC nrog qib siab viscosity swells, cov dej molecules nkag mus qeeb dua thiab cov txheej txheem kev sib xyaw ua ke ntev dua. HPMC nrog qib qis viscosity yooj yim dua rau yaj thiab tsim cov tshuaj thinner.
pH tus nqi ntawm kev daws: HPMC muaj qee qhov kev hloov pauv rau pH tus nqi. HPMC muaj cov nyhuv o zoo dua nyob rau hauv nruab nrab lossis tsis muaj zog acid. Raws li muaj zog acid lossis muaj zog alkaline, cov qauv molecular ntawm HPMC tuaj yeem hloov pauv, yog li cuam tshuam rau nws tus cwj pwm o thiab tawg.
Kev Cuam Tshuam: Qhov concentration ntawm HPMC cov tshuaj hauv dej kuj cuam tshuam rau nws tus cwj pwm o. Ntawm qhov tsis tshua muaj siab, HPMC yooj yim dua kom yaj tag nrho thiab tsim cov tshuaj sib xyaw ntau dua. Ntawm qhov siab siab, kev sib cuam tshuam ntawm HPMC molecules nce, uas yuav ua rau qee cov molecules nyuaj rau yaj tag nrho hauv dej thiab tsim cov gel blocks.
Kev siv tswv yim ntawm HPMC o
Cov khoom o ntawm HPMC ua lub luag haujlwm tseem ceeb hauv kev siv tswv yim. Piv txwv li, hauv kev lag luam kws tshuaj, HPMC tau siv dav hauv cov ntsiav tshuaj tso tawm. Vim tias nws swells hauv dej los tsim cov yeeb yaj kiab colloidal, nws tuaj yeem tswj tau qhov tso tawm ntawm cov tshuaj, yog li ua kom lub sijhawm ntev ntawm kev siv tshuaj.
Hauv kev tsim kho kev lag luam, HPMC feem ntau yog siv los ua cov thickener thiab dej retainer rau cement thiab gypsum-based cov ntaub ntawv. Nws cov khoom o tuaj yeem txhim kho qhov adhesion thiab kev tsim kho ntawm cov ntaub ntawv, thaum tseem khaws cov dej noo, ncua sij hawm teem sijhawm ntawm cov ntaub ntawv, thiab txhim kho cov neeg kho tshuab lub zog thiab qhov smoothness ntawm cov khoom tiav.
Hauv kev lag luam khoom noj khoom haus thiab tshuaj pleev ib ce, HPMC kuj tseem ua lub luag haujlwm tseem ceeb ua cov thickener thiab stabilizer. Nws tus cwj pwm o tuaj yeem muab cov khoom noj kom saj zoo dua thiab kev ntxhib los mos, thaum nyob rau hauv cov tshuaj pleev ib ce, HPMC pab tsim cov ntawv thov zoo thiab khaws cov dej noo.
Tus cwj pwm o ntawm HPMC hauv dej yog qhov tshwm sim ntawm kev sib cuam tshuam ntawm nws cov qauv tshuaj thiab cov dej molecules. Los ntawm kev kho cov yam ntxwv xws li qhov kub thiab txias, pH tus nqi, qib viscosity thiab concentration ntawm cov tshuaj, cov txheej txheem o thiab tawg ntawm HPMC hauv dej tuaj yeem tswj tau kom ua tau raws li qhov xav tau ntawm ntau qhov chaw thov. Cov cuab yeej o ntawm HPMC no tau siv dav hauv ntau qhov kev lag luam, xav txog nws qhov tseem ceeb raws li cov khoom siv polymer.
Post lub sij hawm: Aug-29-2024