Hydroxypropyl methylcellulose (HPMC) yog ib qho tsis-ionic dej-soluble polymer compound tau los ntawm kev hloov kho tshuaj ntawm natural cellulose. Nws yog dav siv nyob rau hauv cov zaub mov, tshuaj, tshuaj pleev ib ce thiab kev tsim kho kev lag luam, tshwj xeeb tshaj yog raws li ib tug nplaum, thickener, emulsifier thiab suspending tus neeg sawv cev nyob rau hauv cov tshuaj npaj. Hauv daim ntawv thov txheej txheem, cov yam ntxwv viscosity ntawm HPMC aqueous tov yog qhov tseem ceeb rau nws qhov kev ua tau zoo hauv ntau qhov chaw.
1. Cov qauv thiab cov khoom ntawm hydroxypropyl methylcellulose
Cov qauv molecular ntawm HPMC muaj ob pawg hloov pauv, hydroxypropyl (-CH₂CHOJ₃) thiab methyl (-OCH₃), uas ua rau nws muaj dej solubility zoo thiab muaj peev xwm hloov kho. HPMC cov saw molecular muaj cov qauv nruj, tab sis nws tseem tuaj yeem tsim cov qauv peb sab hauv cov kua dej, ua rau muaj kev nce ntxiv hauv viscosity. Nws qhov hnyav molecular, hom kev hloov pauv thiab qib kev hloov pauv (piv txwv li, qib ntawm hydroxypropyl thiab methyl hloov pauv ntawm txhua chav tsev) muaj qhov cuam tshuam tseem ceeb ntawm viscosity ntawm cov tshuaj.
2. Viscosity yam ntxwv ntawm aqueous tov
Cov yam ntxwv viscosity ntawm HPMC aqueous tov yog ze ze rau yam xws li cov concentration, molecular hnyav, kub thiab pH tus nqi ntawm cov kuab tshuaj. Feem ntau, cov viscosity ntawm HPMC aqueous tov nce nrog qhov nce ntawm nws cov concentration. Nws cov viscosity qhia tsis yog-Newtonian rheological cwj pwm, uas yog, raws li tus nqi shear nce, lub viscosity ntawm cov tshuaj maj mam txo, uas qhia ib tug shear thinning tshwm sim.
(1) Cov nyhuv ntawm concentration
Muaj qee qhov kev sib raug zoo ntawm viscosity ntawm HPMC aqueous tov thiab nws cov concentration. Raws li cov concentration ntawm HPMC nce, cov molecular kev sib cuam tshuam nyob rau hauv cov aqueous tov yog txhim khu kev qha, thiab entanglement thiab cross-linking ntawm cov molecular chains nce, uas ua rau ib tug nce nyob rau hauv lub viscosity ntawm cov tshuaj. Nyob rau hauv qis concentrations, lub viscosity ntawm HPMC aqueous tov nce linearly nrog qhov nce ntawm concentration, tab sis nyob rau hauv ntau dua concentrations, lub viscosity loj hlob ntawm cov tshuaj nyhav yuav tiaj tus thiab mus txog ib tug ruaj khov tus nqi.
(2) Cov nyhuv ntawm molecular hnyav
Qhov hnyav molecular ntawm HPMC ncaj qha cuam tshuam rau viscosity ntawm nws cov tshuaj aqueous. HPMC nrog qhov hnyav dua molecular muaj cov hlua molecular ntev dua thiab tuaj yeem tsim cov qauv peb-dimensional network ntau dua hauv cov tshuaj aqueous, ua rau muaj viscosity ntau dua. Nyob rau hauv sib piv, HPMC nrog qis molecular hnyav muaj ib tug looser network qauv thiab qis viscosity vim nws luv luv molecular chains. Yog li ntawd, thaum ua ntawv thov, nws yog ib qho tseem ceeb heev uas yuav tau xaiv HPMC nrog ib tug haum molecular hnyav kom ua tau zoo viscosity nyhuv.
(3) Qhov kub thiab txias
Qhov kub thiab txias yog qhov tseem ceeb cuam tshuam rau viscosity ntawm HPMC aqueous tov. Raws li qhov kub thiab txias, qhov txav ntawm cov dej molecules intensifies thiab viscosity ntawm cov tshuaj feem ntau txo. Qhov no yog vim hais tias thaum kub nce, kev ywj pheej ntawm HPMC molecular saw nce thiab kev sib cuam tshuam ntawm molecules tsis muaj zog, yog li txo cov viscosity ntawm cov tshuaj. Txawm li cas los xij, cov lus teb ntawm HPMC los ntawm cov khoom sib txawv lossis cov npe rau qhov kub thiab txias kuj yuav txawv, yog li qhov kub thiab txias yuav tsum tau hloov kho raws li kev thov tshwj xeeb.
(4) Cov nyhuv pH
HPMC nws tus kheej yog ib qho tsis-ionic compound, thiab viscosity ntawm nws cov kua aqueous yog rhiab heev rau cov kev hloov hauv pH. Txawm hais tias HPMC nthuav tawm cov yam ntxwv viscosity ruaj khov nyob rau hauv qhov chaw acidic lossis nruab nrab, qhov solubility thiab viscosity ntawm HPMC yuav raug cuam tshuam rau hauv ib puag ncig acidic lossis alkaline. Piv txwv li, nyob rau hauv muaj zog acid los yog muaj zog alkaline tej yam kev mob, HPMC molecules tej zaum yuav degraded ib feem, yog li txo cov viscosity ntawm nws aqueous tov.
3. Rheological tsom xam ntawm viscosity yam ntxwv ntawm HPMC aqueous tov
Tus cwj pwm rheological ntawm HPMC aqueous tov feem ntau qhia cov yam ntxwv uas tsis yog-Newtonian kua, uas txhais tau hais tias nws cov viscosity tsis tsuas yog cuam tshuam nrog cov ntsiab lus xws li kev daws teeb meem thiab qhov hnyav molecular, tab sis kuj rau shear npaum li cas. Feem ntau hais lus, ntawm tus nqi qis qis, HPMC cov tshuaj aqueous qhia tau tias muaj viscosity ntau dua, thaum lub sij hawm shear npaum li cas, cov viscosity txo. Tus cwj pwm no yog hu ua "shear thinning" lossis "shear thinning" thiab tseem ceeb heev hauv ntau qhov kev siv tswv yim. Piv txwv li, hauv thaj chaw ntawm cov txheej txheem, kev npaj tshuaj, kev ua zaub mov, thiab lwm yam, cov yam ntxwv ntawm cov shear thinning ntawm HPMC tuaj yeem ua kom ntseeg tau tias cov viscosity siab yog khaws cia thaum siv qis qis, thiab nws tuaj yeem ntws tau yooj yim dua nyob rau hauv high-speed shear tej yam kev mob.
4. Lwm yam cuam tshuam rau viscosity ntawm HPMC aqueous tov
(1) Cov nyhuv ntsev
Qhov sib ntxiv ntawm cov ntsev ntsev (xws li sodium chloride) tuaj yeem ua kom cov viscosity ntawm HPMC aqueous tov. Qhov no yog vim ntsev tuaj yeem txhim kho kev sib cuam tshuam ntawm cov molecules los ntawm kev hloov lub zog ionic ntawm cov tshuaj, kom HPMC molecules tsim cov qauv sib txuas ntau dua, yog li nce viscosity. Txawm li cas los xij, cov txiaj ntsig ntawm ntsev hom thiab concentration ntawm viscosity kuj yuav tsum tau kho raws li cov xwm txheej tshwj xeeb.
(2) Cov nyhuv ntawm lwm yam additives
Ntxiv lwm cov tshuaj ntxiv (xws li surfactants, polymers, thiab lwm yam) rau HPMC aqueous tov yuav cuam tshuam rau viscosity. Piv txwv li, surfactants yuav txo cov viscosity ntawm HPMC, tshwj xeeb tshaj yog thaum cov surfactant concentration siab. Tsis tas li ntawd, qee cov polymers lossis cov khoom tuaj yeem cuam tshuam nrog HPMC thiab hloov cov khoom rheological ntawm nws cov tshuaj.
Cov yam ntxwv viscosity ntawmHydroxypropyl methylcellulose yog tsim los ntawm cov tshuaj Cov tshuaj aqueous raug cuam tshuam los ntawm ntau yam, suav nrog cov concentration, qhov hnyav molecular, qhov kub thiab txias, pH tus nqi, thiab lwm yam HPMC aqueous tov feem ntau nthuav tawm cov khoom tsis yog-Newtonian rheological, muaj cov thickening zoo thiab shear thinning zog, thiab yog dav siv nyob rau hauv ntau yam kev lag luam thiab chaw muag tshuaj. Kev nkag siab thiab paub txog cov yam ntxwv viscosity no yuav pab txhim kho kev siv HPMC hauv ntau daim ntawv thov. Hauv kev siv cov tswv yim, HPMC hom thiab cov txheej txheem tsim nyog yuav tsum raug xaiv raws li cov kev xav tau tshwj xeeb kom tau txais qhov zoo tshaj plaws viscosity thiab rheological zog.
Post lub sij hawm: Mar-01-2025