Hydroxypropyl methylcellulose (HPMC) yog ib qho tshuaj polymer uas tsis yaj hauv dej uas tau los ntawm kev hloov kho tshuaj ntawm cov cellulose ntuj. Nws yog siv dav hauv kev lag luam khoom noj, tshuaj, tshuaj pleev ib ce thiab kev tsim kho, tshwj xeeb tshaj yog ua cov nplaum, cov khoom ua kom tuab, cov khoom ua kom emulsifier thiab cov neeg sawv cev rau kev npaj tshuaj. Hauv cov txheej txheem thov, cov yam ntxwv viscosity ntawm HPMC aqueous kua yog qhov tseem ceeb rau nws cov kev ua tau zoo hauv ntau qhov chaw sib txawv.
1. Cov qauv thiab cov khoom ntawm hydroxypropyl methylcellulose
Cov qauv molecular ntawm HPMC muaj ob pawg hloov pauv, hydroxypropyl (-CH₂CHOHCH₃) thiab methyl (-OCH₃), uas ua rau nws muaj cov dej zoo solubility thiab hloov pauv tau. Lub HPMC molecular saw muaj qee qhov qauv nruj, tab sis nws kuj tseem tuaj yeem tsim cov qauv network peb-seem hauv cov kua dej, ua rau muaj kev nce ntxiv ntawm viscosity. Nws qhov hnyav molecular, hom substituent thiab degree ntawm kev hloov pauv (piv txwv li, degree ntawm hydroxypropyl thiab methyl hloov pauv ntawm txhua chav tsev) muaj kev cuam tshuam tseem ceeb rau viscosity ntawm cov kua.
2. Cov yam ntxwv ntawm viscosity ntawm cov kua dej
Cov yam ntxwv ntawm viscosity ntawm HPMC aqueous kua muaj feem cuam tshuam nrog cov yam xws li qhov concentration, qhov hnyav molecular, kub thiab pH tus nqi ntawm cov kuab tshuaj. Feem ntau, qhov viscosity ntawm HPMC aqueous kua nce nrog rau qhov nce ntawm nws qhov concentration. Nws viscosity qhia txog tus cwj pwm rheological tsis-Newtonian, uas yog, thaum tus nqi shear nce, qhov viscosity ntawm cov kua maj mam txo qis, qhia txog qhov tshwm sim shear thinning.
(1) Cov nyhuv ntawm kev sib sau ua ke
Muaj qee qhov kev sib raug zoo ntawm qhov viscosity ntawm HPMC aqueous kua thiab nws qhov concentration. Raws li qhov concentration ntawm HPMC nce, qhov kev sib cuam tshuam molecular hauv cov kua aqueous tau txhim kho, thiab qhov kev sib txuas thiab kev sib txuas ntawm cov saw hlau molecular nce, ua rau muaj kev nce ntxiv ntawm qhov viscosity ntawm cov kua. Ntawm qhov concentration qis dua, qhov viscosity ntawm HPMC aqueous kua nce linearly nrog qhov nce ntawm qhov concentration, tab sis ntawm qhov concentration siab dua, qhov kev loj hlob ntawm viscosity ntawm cov kua feem ntau yog tiaj tus thiab ncav cuag tus nqi ruaj khov.
(2) Cov nyhuv ntawm qhov hnyav molecular
Qhov hnyav molecular ntawm HPMC cuam tshuam ncaj qha rau qhov viscosity ntawm nws cov kua dej. HPMC nrog qhov hnyav molecular siab dua muaj cov saw molecular ntev dua thiab tuaj yeem tsim cov qauv network peb-seem nyuaj dua hauv cov kua dej, ua rau muaj viscosity siab dua. Hauv kev sib piv, HPMC nrog qhov hnyav molecular qis dua muaj cov qauv network xoob dua thiab viscosity qis dua vim nws cov saw molecular luv dua. Yog li ntawd, thaum thov, nws yog ib qho tseem ceeb heev uas yuav tsum xaiv HPMC nrog qhov hnyav molecular tsim nyog kom ua tiav qhov viscosity zoo tagnrho.
(3) Qhov cuam tshuam ntawm qhov kub thiab txias
Kub yog ib qho tseem ceeb uas cuam tshuam rau qhov viscosity ntawm HPMC aqueous kua. Thaum qhov kub nce ntxiv, kev txav ntawm cov dej molecules nce ntxiv thiab qhov viscosity ntawm cov kua feem ntau txo qis. Qhov no yog vim tias thaum qhov kub nce ntxiv, kev ywj pheej ntawm HPMC molecular saw nce ntxiv thiab kev sib cuam tshuam ntawm cov molecules tsis muaj zog, yog li txo qhov viscosity ntawm cov kua. Txawm li cas los xij, cov lus teb ntawm HPMC los ntawm ntau pawg lossis hom rau qhov kub kuj tseem yuav txawv, yog li cov xwm txheej kub yuav tsum tau kho raws li cov kev xav tau ntawm daim ntawv thov tshwj xeeb.
(4) Cov nyhuv ntawm tus nqi pH
HPMC nws tus kheej yog ib qho tshuaj tsis-ionic, thiab qhov viscosity ntawm nws cov kua dej yog rhiab heev rau kev hloov pauv hauv pH. Txawm hais tias HPMC qhia txog cov yam ntxwv viscosity ruaj khov hauv cov chaw acidic lossis nruab nrab, qhov solubility thiab viscosity ntawm HPMC yuav raug cuam tshuam hauv cov chaw acidic lossis alkaline heev. Piv txwv li, nyob rau hauv cov kua qaub muaj zog lossis cov xwm txheej alkaline muaj zog, cov molecules HPMC yuav raug rhuav tshem ib feem, yog li txo qhov viscosity ntawm nws cov kua dej.
3. Kev tshuaj xyuas rheological ntawm cov yam ntxwv viscosity ntawm HPMC aqueous kua
Tus cwj pwm rheological ntawm HPMC aqueous kua feem ntau qhia txog cov yam ntxwv tsis yog Newtonian kua, uas txhais tau tias nws viscosity tsis yog tsuas yog cuam tshuam nrog cov yam xws li cov concentration ntawm cov tshuaj thiab qhov hnyav molecular, tab sis kuj tseem cuam tshuam nrog shear rate. Feem ntau hais lus, ntawm qhov shear rates qis, HPMC aqueous kua qhia viscosity siab dua, thaum lub shear rate nce, viscosity txo qis. Tus cwj pwm no hu ua "shear thinning" lossis "shear thinning" thiab tseem ceeb heev rau ntau yam kev siv. Piv txwv li, hauv cov teb ntawm cov txheej txheem, kev npaj tshuaj, kev ua zaub mov, thiab lwm yam, cov yam ntxwv shear thinning ntawm HPMC tuaj yeem ua kom ntseeg tau tias viscosity siab tau khaws cia thaum lub sijhawm siv qis-ceev, thiab nws tuaj yeem ntws tau yooj yim dua nyob rau hauv cov xwm txheej high-speed shear.
4. Lwm yam tseem ceeb uas cuam tshuam rau qhov viscosity ntawm HPMC aqueous kua
(1) Cov nyhuv ntawm ntsev
Qhov ntxiv cov ntsev solutes (xws li sodium chloride) tuaj yeem ua rau kom cov viscosity ntawm HPMC aqueous kua. Qhov no yog vim tias ntsev tuaj yeem txhim kho kev sib cuam tshuam ntawm cov molecules los ntawm kev hloov pauv lub zog ionic ntawm cov kua, yog li ntawd HPMC molecules tsim cov qauv network compact dua, yog li ua rau kom viscosity nce ntxiv. Txawm li cas los xij, qhov cuam tshuam ntawm hom ntsev thiab kev sib sau ua ke ntawm viscosity kuj tseem yuav tsum tau kho raws li cov xwm txheej tshwj xeeb.
(2) Cov nyhuv ntawm lwm cov khoom ntxiv
Ntxiv lwm yam khoom ntxiv (xws li surfactants, polymers, thiab lwm yam) rau hauv HPMC aqueous kua kuj tseem yuav cuam tshuam rau viscosity. Piv txwv li, surfactants yuav txo qhov viscosity ntawm HPMC, tshwj xeeb tshaj yog thaum qhov concentration ntawm surfactant siab. Tsis tas li ntawd, qee cov polymers lossis cov khoom me me kuj tuaj yeem cuam tshuam nrog HPMC thiab hloov cov khoom rheological ntawm nws cov kua.
Cov yam ntxwv ntawm viscosityhydroxypropyl methylcellulose Cov kua dej raug cuam tshuam los ntawm ntau yam, suav nrog kev sib xyaw, qhov hnyav molecular, kub, pH tus nqi, thiab lwm yam. HPMC cov kua dej feem ntau ua rau pom cov khoom tsis yog Newtonian rheological, muaj cov khoom zoo thickening thiab shear thinning, thiab siv dav hauv ntau yam kev lag luam thiab tshuaj. Kev nkag siab thiab kev paub txog cov yam ntxwv viscosity no yuav pab ua kom zoo dua kev siv HPMC hauv ntau daim ntawv thov. Hauv kev siv tiag tiag, hom HPMC thiab cov txheej txheem tsim nyog yuav tsum tau xaiv raws li qhov xav tau tshwj xeeb kom tau txais cov viscosity zoo tagnrho thiab rheological.
Lub sijhawm tshaj tawm: Lub Peb Hlis-01-2025