Hydroxypropyl methylcellulose (HPMC) yog cov khoom siv ntau yam polymer dav siv los ua cov thickener hauv ntau yam lag luam xws li tshuaj, tshuaj pleev ib ce, khoom noj khoom haus, thiab cov khoom siv tsim kho. Nkag siab txog cov khoom rheological ntawm HPMC thickener systems yog qhov tseem ceeb rau kev txhim kho lawv cov kev ua tau zoo hauv ntau daim ntawv thov.
1. Viscosity:
HPMC thickener systems qhia shear-thinning tus cwj pwm, txhais tau tias lawv viscosity txo nrog nce shear npaum li cas. Cov cuab yeej no muaj txiaj ntsig zoo hauv cov ntawv thov uas yuav tsum tau siv yooj yim los yog ua tiav, xws li hauv cov xim thiab txheej.
Lub viscosity ntawm HPMC cov kev daws teeb meem yog cuam tshuam los ntawm cov khoom xws li polymer concentration, molecular hnyav, hloov degree, kub, thiab shear rate.
Ntawm tus nqi qis qis, HPMC cov kev daws teeb meem coj zoo li cov kua nplaum uas muaj viscosity siab, thaum nyob rau ntawm cov nqi shear siab, lawv coj zoo li cov kua nplaum tsawg, ua kom yooj yim ntws.
2. Thixotropy:
Thixotropy hais txog cov cuab yeej ntawm qee cov kua dej kom rov qab tau lawv cov viscosity thaum sawv tom qab raug kev nyuaj siab. HPMC thickener systems feem ntau pom tus cwj pwm thixotropic.
Thaum raug shear kev nyuaj siab, ntev polymer chains nyob rau hauv cov kev taw qhia ntawm ntws, txo viscosity. Thaum xaus ntawm kev ntxhov siab shear, cov saw hlau polymer maj mam rov qab mus rau lawv qhov kev taw qhia random, ua rau muaj kev nce ntxiv hauv viscosity.
Thixotropy yog ntshaw nyob rau hauv daim ntawv thov xws li coatings thiab adhesives, qhov twg cov khoom yuav tsum tau kom muaj kev ruaj ntseg thaum lub sij hawm daim ntawv thov tab sis ntws yooj yim nyob rau hauv shear.
3. Yield Stress:
HPMC thickener systems feem ntau muaj kev ntxhov siab, uas yog qhov kev ntxhov siab tsawg kawg nkaus yuav tsum tau pib ntws. Hauv qab no kev ntxhov siab, cov khoom siv coj zoo li cov khoom, nthuav tawm tus cwj pwm elastic.
Cov txiaj ntsig kev ntxhov siab ntawm HPMC cov kev daws teeb meem yog nyob ntawm cov khoom xws li polymer concentration, molecular hnyav, thiab kub.
Kev ntxhov siab yog qhov tseem ceeb hauv cov ntawv thov uas cov khoom yuav tsum tau nyob hauv qhov chaw yam tsis tau ntws los ntawm nws tus kheej qhov hnyav, xws li hauv cov txheej ntsug lossis hauv kev ncua ntawm cov khoom hauv cov xim.
4. Temperature Sensitivity:
Lub viscosity ntawm HPMC cov kev daws teeb meem yog cuam tshuam los ntawm qhov kub thiab txias, nrog viscosity feem ntau yuav txo qis thaum kub nce. Cov cwj pwm no yog ib yam ntawm cov kev daws teeb meem polymer.
Qhov kub thiab txias tuaj yeem cuam tshuam qhov sib xws thiab kev ua tau zoo ntawm HPMC thickener systems nyob rau hauv ntau daim ntawv thov, yuav tsum tau hloov kho nyob rau hauv formulation los yog cov txheej txheem tsis tswj cov yam xav tau nyob rau hauv txawv kub ntau yam.
5. Shear Rate Dependence:
Lub viscosity ntawm HPMC cov kev daws teeb meem yog nyob ntawm seb tus nqi shear, nrog cov nqi shear ntau dua ua rau qis viscosity vim qhov sib dhos thiab ncab ntawm cov saw hlau polymer.
Qhov kev txiav txim siab ntawm qhov kev cia siab no feem ntau tau piav qhia los ntawm lub hwj chim-txoj cai lossis Herschel-Bulkley qauv, uas cuam tshuam txog kev ntxhov siab rau shear npaum li cas thiab cov txiaj ntsig kev ntxhov siab.
Kev nkag siab txog qhov kev cia siab ntawm tus nqi qis yog qhov tseem ceeb rau kev kwv yees thiab tswj tus cwj pwm ntws ntawm HPMC cov txheej txheem thickener hauv kev siv tswv yim.
6. Kev Cuam Tshuam Los:
Kev nce qib ntawm HPMC hauv kev daws teeb meem feem ntau ua rau muaj kev nce ntxiv hauv viscosity thiab tawm los ntawm kev ntxhov siab. Cov nyhuv concentration no yog qhov tseem ceeb rau kev ua tiav qhov xav tau sib xws thiab kev ua tau zoo hauv ntau yam kev siv.
Txawm li cas los xij, ntawm qhov muaj siab heev, HPMC cov kev daws teeb meem tuaj yeem pom tus cwj pwm zoo li gel, tsim cov qauv sib txuas uas ua rau kom muaj viscosity thiab ua rau muaj kev ntxhov siab.
7. Sib tov thiab dispersion:
Kev sib xyaw kom zoo thiab tawg ntawm HPMC hauv kev daws yog qhov tseem ceeb rau kev ua tiav cov viscosity thiab rheological zog thoob plaws hauv lub cev.
Tsis tiav dispersion los yog agglomeration ntawm HPMC hais tuaj yeem ua rau tsis zoo ib yam viscosity thiab kev cuam tshuam kev ua haujlwm hauv cov ntawv thov xws li txheej thiab cov nplaum.
Ntau yam kev sib xyaw ua ke thiab cov khoom siv ntxiv tuaj yeem ua haujlwm kom ntseeg tau tias kev ua kom pom kev zoo thiab kev ua haujlwm ntawm HPMC thickener systems.
Cov khoom rheological ntawm HPMC thickener systems, suav nrog viscosity, thixotropy, yield stress, kub rhiab heev, shear rate dependence, concentration los, thiab mixing / dispersion cwj pwm, plays lub luag hauj lwm tseem ceeb hauv kev txiav txim siab lawv cov kev ua tau zoo nyob rau hauv ntau yam kev siv. Kev nkag siab thiab tswj cov khoom no yog qhov tseem ceeb rau kev tsim cov khoom HPMC raws li qhov xav tau sib xws, ruaj khov, thiab ua haujlwm.
Post lub sij hawm: May-08-2024