Yuav ua li cas lub viscosity ntawm HPMC aqueous tov hloov nrog concentration?

Hydroxypropyl Methylcellulose (HPMC) yog kev hloov kho cellulose ether dav siv hauv kev npaj tshuaj, khoom noj khoom haus, khoom siv hauv tsev, tshuaj pleev ib ce thiab lwm yam. HPMC muaj thickening, film-forming, adhesion thiab lwm yam khoom. Kev sib raug zoo ntawm viscosity thiab concentration ntawm nws cov kua aqueous yog qhov tseem ceeb rau ntau yam kev siv.

Cov yam ntxwv viscosity ntawm HPMC aqueous kua

Cov yam ntxwv tseem ceeb
HPMC tsim cov pob tshab lossis cov kua nplaum nplaum tom qab yaj hauv dej. Nws cov viscosity cuam tshuam tsis tsuas yog los ntawm qhov concentration ntawm HPMC, tab sis kuj los ntawm cov yam ntxwv xws li qhov hnyav molecular, hloov pauv hom thiab qhov ntsuas kub.

Molecular Luj: Qhov loj dua qhov hnyav molecular ntawm HPMC, qhov kev daws viscosity ntau dua. Qhov no yog vim hais tias cov macromolecules tsim ib tug complex entangled qauv nyob rau hauv cov tshuaj, uas ua rau kom muaj kev sib txhuam ntawm molecules.
Hom Hloov: Qhov piv ntawm methoxy thiab hydroxypropoxy hloov pauv cuam tshuam rau kev solubility thiab viscosity ntawm HPMC. Feem ntau, thaum cov ntsiab lus methoxy yog siab dua, cov solubility ntawm HPMC zoo dua thiab cov viscosity ntawm cov tshuaj kuj siab dua.

Kev sib raug zoo ntawm concentration thiab viscosity

Dilute kua theem:
Thaum cov concentration ntawm HPMC tsawg, kev sib cuam tshuam ntawm cov molecules tsis muaj zog thiab cov tshuaj muaj cov khoom siv Newtonian kua, uas yog, cov viscosity yog ib txwm ywj siab ntawm tus nqi shear.
Nyob rau theem no, viscosity ntawm cov tshuaj nce linearly nrog nce concentration. Qhov kev sib raug zoo no tuaj yeem qhia tau los ntawm kev sib npaug viscosity yooj yim:

Nws tuaj yeem pom los ntawm cov ntaub ntawv uas cov viscosity ntawm HPMC aqueous tov nce exponentially nrog qhov nce hauv concentration. Qhov kev loj hlob no yuav tshwm sim ntawm daim duab raws li qhov nkhaus nce siab, tshwj xeeb tshaj yog nyob rau hauv cov cheeb tsam siab.

Kev cuam tshuam
Cov nyhuv ntawm qhov kub thiab txias
Qhov kub thiab txias muaj qhov cuam tshuam loj rau qhov viscosity ntawm HPMC cov tshuaj. Feem ntau hais lus, qhov nce ntawm qhov kub thiab txias txo qhov viscosity ntawm cov tshuaj. Qhov no yog vim qhov kub thiab txias ua rau muaj zog molecular zog thiab tsis muaj zog ntawm kev sib cuam tshuam ntawm molecular chains, yog li txo viscosity.

Qhov cuam tshuam ntawm shear rate
Rau cov kev daws teeb meem HPMC siab, cov viscosity kuj cuam tshuam los ntawm tus nqi shear. Ntawm qhov siab shear tus nqi, kev taw qhia ntawm cov saw hlau molecular yuav ua tau zoo ib yam thiab kev sib txhuam sab hauv yog txo, ua rau kom pom tseeb viscosity ntawm cov tshuaj. Qhov tshwm sim no hu ua shear thinning.

Daim ntawv thov
Hauv kev npaj tshuaj, HPMC feem ntau yog siv rau hauv cov ntsiav tshuaj txheej, cov ntawv tso tawm ntau npaum li cas, thiab cov thickeners. To taub yuav ua li cas cov viscosity ntawm HPMC aqueous daws hloov nrog concentration yog qhov tseem ceeb rau kev tsim cov tshuaj tsim nyog. Piv txwv li, hauv cov ntsiav tshuaj txheej, qhov tsim nyog HPMC concentration tuaj yeem ua kom ntseeg tau tias cov kua txheej txheej muaj viscosity txaus los npog cov ntsiav tshuaj saum npoo, thaum tsis siab dhau los ua nyuaj.

Hauv kev lag luam zaub mov, HPMC yog siv los ua cov thickener thiab stabilizer. Kev nkag siab txog kev sib raug zoo ntawm cov concentration thiab viscosity tuaj yeem pab txiav txim siab qhov kev pom zoo kom ntseeg tau qhov saj thiab kev ntxhib los mos ntawm cov khoom noj.

Lub viscosity ntawm HPMC aqueous tov muaj qhov zoo sib xws nrog cov concentration. Nws qhia tau hais tias ib qho kev nce ntxiv hauv cov txheej txheem dilute daws thiab ib qho kev nce ntxiv hauv cov concentration siab. Cov yam ntxwv viscosity no yog qhov tseem ceeb hauv ntau yam kev siv hauv kev lag luam, thiab kev nkag siab thiab tswj kev hloov pauv viscosity ntawm HPMC yog qhov tseem ceeb heev rau kev ua kom zoo dua thiab txhim kho cov khoom zoo.