Hydroxypropyl Methylcellulose (HPMC) yog ib qho tseem ceeb ntawm cov dej-soluble polymer dav siv hauv kev lag luam, zaub mov, txheej, khoom siv hauv tsev thiab lwm yam. Cov tshuaj viscosity ntawm HPMC yog qhov tseem ceeb cuam tshuam rau nws cov kev ua tau zoo thiab kev siv, thiab qhov kub thiab txias muaj qhov cuam tshuam loj rau cov viscosity ntawm HPMC aqueous tov.
1. Viscosity yam ntxwv ntawm HPMC tov
HPMC yog cov khoom siv polymer nrog thermally reversible dissolution zog. Thaum HPMC yaj nyob rau hauv dej, cov tshuaj aqueous tsim muaj cov yam ntxwv uas tsis yog-Newtonian kua, uas yog, cov tshuaj viscosity hloov nrog cov kev hloov ntawm shear npaum li cas. Ntawm qhov kub thiab txias, HPMC cov kev daws teeb meem feem ntau coj tus cwj pwm pseudoplastic kua, uas yog, lawv muaj cov viscosity ntau dua ntawm qhov qis shear, thiab cov viscosity txo qis thaum shear rate nce.
2. Cov nyhuv ntawm qhov kub thiab txias ntawm cov viscosity ntawm HPMC tov
Kev hloov pauv kub muaj ob lub ntsiab cuam tshuam rau lub viscosity ntawm HPMC aqueous daws: nce thermal zog ntawm molecular chains thiab kev hloov hauv kev sib cuam tshuam.
(1) Thermal txav ntawm molecular chains nce
Thaum qhov kub thiab txias nce, lub thermal txav ntawm HPMC molecular saw nce, uas ua rau cov hydrogen bonds thiab van der Waals rog ntawm cov molecules kom tsis muaj zog thiab fluidity ntawm cov tshuaj kom nce. Lub viscosity ntawm cov tshuaj txo qis vim qhov txo qis entanglement thiab lub cev cross-linking ntawm molecular chains. Yog li ntawd, HPMC aqueous daws teeb pom kev qis dua viscosity ntawm qhov kub siab dua.
(2) Kev hloov pauv hauv kev daws teeb meem
Kev hloov kub tuaj yeem cuam tshuam rau kev solubility ntawm HPMC molecules hauv dej. HPMC yog ib qho polymer nrog cov khoom siv thermogelling, thiab nws cov solubility hauv dej hloov pauv nrog qhov kub thiab txias. Ntawm qhov kub thiab txias, cov pab pawg hydrophilic ntawm HPMC molecular saw tsim ruaj khov hydrogen bonds nrog dej molecules, yog li tuav zoo solubility thiab siab viscosity. Txawm li cas los xij, thaum qhov kub thiab txias nce mus rau ib theem, kev sib cuam tshuam ntawm hydrophobic ntawm HPMC molecular chains yog txhim kho, ua rau muaj kev tsim ntawm peb-dimensional network qauv los yog gelation nyob rau hauv cov tshuaj, ua rau cov tshuaj viscosity dheev nce nyob rau hauv tej yam kev mob. Qhov tshwm sim no hu ua Nws yog "thermal gel" phenomenon.
3. Kev soj ntsuam ntawm qhov kub thiab txias ntawm HPMC kua viscosity
Cov kev tshawb fawb soj ntsuam tau pom tias nyob rau hauv ib qho kev ntsuas kub (piv txwv li, 20 ° C mus rau 40 ° C), viscosity ntawm HPMC aqueous daws maj mam txo nrog nce kub. Qhov no yog vim tias qhov kub siab dua ua rau lub zog kinetic ntawm cov saw hlau molecular thiab txo cov kev sib cuam tshuam hauv nruab nrab, yog li txo cov kev sib txhuam sab hauv ntawm cov tshuaj. Txawm li cas los xij, thaum qhov kub thiab txias tseem nce mus rau qhov ntsuas kub ntawm HPMC (feem ntau ntawm 60 ° C thiab 90 ° C, nyob ntawm qhov hloov pauv thiab qhov hnyav molecular ntawm HPMC), cov tshuaj viscosity dheev nce. Qhov tshwm sim ntawm qhov tshwm sim no muaj feem xyuam nrog kev sib koom ua ke thiab sib sau ua ke ntawm HPMC molecular chains.
4. Kev sib raug zoo ntawm qhov kub thiab txias thiab HPMC cov yam ntxwv tsis
Cov tshuaj viscosity ntawm HPMC tsis tsuas yog cuam tshuam los ntawm qhov kub thiab txias, tab sis kuj tseem cuam tshuam nrog nws cov qauv molecular. Piv txwv li, qib ntawm kev hloov pauv (piv txwv li, cov ntsiab lus ntawm hydroxypropyl thiab methyl substituents) thiab molecular hnyav ntawm HPMC muaj kev cuam tshuam loj rau nws tus cwj pwm thermal gel. HPMC nrog rau qib siab ntawm kev hloov pauv tswj qhov qis qis hauv qhov dav ntawm qhov kub thiab txias vim nws cov pab pawg hydrophilic ntau dua, thaum HPMC nrog cov qib qis ntawm kev hloov pauv ntau dua yuav tsim cov thermal gels. Tsis tas li ntawd, HPMC cov kev daws teeb meem nrog qhov hnyav dua molecular ntau dua yuav ua rau muaj viscosity ntawm qhov kub thiab txias.
5. Kev xav txog kev lag luam thiab kev siv tswv yim
Hauv kev siv cov tswv yim, cov hom HPMC tsim nyog yuav tsum raug xaiv raws li qhov kub thiab txias. Piv txwv li, nyob rau hauv ib puag ncig kub, HPMC nrog kub kuj yuav tsum tau xaiv kom tsis txhob thermal gelation. Nyob rau hauv qhov kub thiab txias, qhov solubility thiab viscosity stability ntawm HPMC yuav tsum xav txog.
Qhov cuam tshuam ntawm qhov kub ntawm qhov viscosity ntawm HPMC aqueous tov muaj qhov tseem ceeb ntawm kev siv. Hauv kev lag luam tshuaj, HPMC feem ntau yog siv los ua cov ntaub ntawv tso tawm rau kev npaj tshuaj, thiab nws cov yam ntxwv viscosity cuam tshuam ncaj qha rau cov tshuaj tso tawm. Hauv kev lag luam khoom noj khoom haus, HPMC yog siv los txhim kho kev ntxhib los mos thiab ruaj khov ntawm cov khoom, thiab qhov kub thiab txias ntawm nws cov tshuaj viscosity yuav tsum tau hloov kho raws li qhov ua haujlwm kub. Hauv kev tsim cov ntaub ntawv, HPMC yog siv los ua cov thickener thiab cov dej tuav, thiab nws cov yam ntxwv viscosity cuam tshuam rau kev tsim kho thiab cov khoom siv zog.
Cov nyhuv ntawm qhov kub thiab txias ntawm viscosity ntawm HPMC aqueous tov yog txheej txheem nyuaj uas cuam tshuam nrog thermal txav ntawm cov saw hlau molecular, kev daws teeb meem, thiab cov yam ntxwv ntawm cov polymer. Zuag qhia tag nrho, cov viscosity ntawm HPMC aqueous daws feem ntau txo nrog qhov kub thiab txias, tab sis nyob rau hauv tej qhov kub thiab txias, thermal gelation yuav tshwm sim. Kev nkag siab txog tus yam ntxwv no muaj qhov tseem ceeb qhia qhov tseem ceeb rau kev siv tswv yim thiab kev ua kom zoo ntawm HPMC.
Post lub sij hawm: Lub Xya hli ntuj-10-2024