Hydroxypropyl Methylcellulose (HPMC) yog ib qho tseem ceeb ntawm cellulose ether derivative uas tau siv dav hauv ntau qhov chaw lag luam vim nws cov khoom siv lub cev thiab tshuaj lom neeg tshwj xeeb. Nws cov khoom viscosity yog ib qho ntawm cov khoom tseem ceeb tshaj plaws ntawm HPMC, uas cuam tshuam ncaj qha rau nws cov kev ua tau zoo hauv ntau yam kev siv.
1. Cov khoom tseem ceeb ntawm HPMC
HPMC yog ib qho cellulose ether uas tsis yog ionic tau los ntawm kev hloov ib feem ntawm cov hydroxyl pawg (-OH) hauv cov cellulose molecule nrog cov pawg methoxy (-OCH3) thiab cov pawg hydroxypropyl (-OCH2CH(OH)CH3). Nws muaj kev yaj zoo hauv dej thiab qee cov kuab tshuaj organic, tsim cov tshuaj colloidal pob tshab. Qhov viscosity ntawm HPMC feem ntau yog txiav txim siab los ntawm nws qhov hnyav molecular, qib ntawm kev hloov pauv (DS, Qib ntawm Kev Hloov Pauv) thiab kev faib tawm ntawm cov khoom hloov pauv.
2. Kev txiav txim siab ntawm viscosity ntawm HPMC
Qhov viscosity ntawm HPMC cov tshuaj feem ntau yog ntsuas siv lub rotational viscometer lossis capillary viscometer. Thaum ntsuas, yuav tsum tau them sai sai rau qhov concentration, kub thiab shear rate ntawm cov tshuaj, vim tias cov yam no tuaj yeem cuam tshuam rau qhov viscosity.
Kev sib xyaw ua ke ntawm cov tshuaj: Qhov viscosity ntawm HPMC nce nrog rau qhov nce ntawm kev sib xyaw ua ke ntawm cov tshuaj. Thaum qhov concentration ntawm HPMC kua qis dua, kev sib cuam tshuam ntawm cov molecule tsis muaj zog thiab qhov viscosity qis dua. Thaum qhov concentration nce ntxiv, kev sib koom ua ke thiab kev sib cuam tshuam ntawm cov molecule nce ntxiv, ua rau muaj kev nce ntxiv ntawm viscosity.
Kub: Qhov viscosity ntawm HPMC cov tshuaj muaj qhov rhiab heev rau qhov kub thiab txias. Feem ntau, thaum qhov kub nce ntxiv, qhov viscosity ntawm HPMC cov tshuaj yuav txo qis. Qhov no yog vim qhov kub thiab txias nce ntxiv ua rau muaj kev txav mus los ntawm cov molecular thiab kev sib cuam tshuam ntawm cov molecular tsis muaj zog. Nws yuav tsum tau sau tseg tias HPMC nrog ntau qib ntawm kev hloov pauv thiab qhov hnyav molecular muaj qhov rhiab heev rau qhov kub thiab txias sib txawv.
Tus nqi txiav: Cov kev daws teeb meem HPMC qhia txog tus cwj pwm pseudoplastic (shear thinning), piv txwv li qhov viscosity siab dua ntawm tus nqi txiav qis thiab txo qis ntawm tus nqi txiav siab. Tus cwj pwm no yog vim muaj cov zog txiav uas sib dhos cov saw hlau molecular raws li kev taw qhia txiav, yog li txo cov kev sib txuas thiab kev sib cuam tshuam ntawm cov molecules.
3. Cov yam ntxwv cuam tshuam rau HPMC viscosity
Qhov hnyav molecular: Qhov hnyav molecular ntawm HPMC yog ib qho ntawm cov yam tseem ceeb uas txiav txim siab nws qhov viscosity. Feem ntau hais lus, qhov loj dua qhov hnyav molecular, qhov siab dua qhov viscosity ntawm cov tshuaj. Qhov no yog vim tias HPMC molecules nrog qhov hnyav molecular siab yuav tsim cov tes hauj lwm sib txuas, yog li ua rau muaj kev sib txhuam sab hauv ntawm cov tshuaj.
Qib ntawm kev hloov pauv thiab kev faib tawm ntawm cov khoom hloov pauv: Tus lej thiab kev faib tawm ntawm methoxy thiab hydroxypropyl substituents hauv HPMC kuj cuam tshuam rau nws qhov viscosity. Feem ntau, qhov siab dua ntawm methoxy substituents (DS), qhov qis dua qhov viscosity ntawm HPMC, vim tias kev qhia txog methoxy substituents yuav txo qhov hydrogen bonding force ntawm cov molecules. Kev qhia txog hydroxypropyl substituents yuav ua rau muaj kev sib cuam tshuam ntawm intermolecular, yog li ua rau muaj viscosity ntau ntxiv. Tsis tas li ntawd, kev faib tawm ntawm cov khoom hloov pauv pab tsim kom muaj kev daws teeb meem ruaj khov thiab ua rau muaj viscosity ntawm cov tshuaj.
Tus nqi pH ntawm cov tshuaj: Txawm hais tias HPMC yog cov polymer uas tsis yog ionic thiab nws cov viscosity tsis rhiab rau kev hloov pauv ntawm tus nqi pH ntawm cov tshuaj, cov nqi pH siab heev (acidic heev lossis alkaline heev) yuav ua rau muaj kev puas tsuaj ntawm cov qauv molecular ntawm HPMC, yog li cuam tshuam rau qhov viscosity.
4. Cov teb thov ntawm HPMC
Vim nws cov yam ntxwv viscosity zoo heev, HPMC siv dav hauv ntau qhov chaw:
Cov ntaub ntawv siv hauv tsev: Hauv cov ntaub ntawv siv hauv tsev, HPMC yog siv los ua cov khoom ua kom tuab thiab khaws dej kom txhim kho kev ua haujlwm ntawm kev tsim kho thiab ua kom tsis txhob tawg.
Kev lag luam tshuaj: Hauv kev lag luam tshuaj, HPMC yog siv los ua cov khoom siv rau cov ntsiav tshuaj, tus neeg sawv cev tsim zaj duab xis rau cov tshuaj ntsiav thiab tus nqa khoom rau cov tshuaj tso tawm tas mus li.
Kev lag luam zaub mov: HPMC yog siv los ua cov khoom siv tuab thiab stabilizer hauv kev lag luam zaub mov rau kev tsim cov ice cream, jelly thiab cov khoom noj siv mis.
Cov khoom siv tshuaj txhua hnub: Hauv cov khoom siv tshuaj txhua hnub, HPMC yog siv los ua cov khoom siv tuab thiab stabilizer rau kev tsim cov tshuaj zawv plaub hau, da dej gel, tshuaj txhuam hniav, thiab lwm yam.
Cov yam ntxwv viscosity ntawm HPMC yog lub hauv paus rau nws qhov kev ua tau zoo heev hauv ntau yam kev siv. Los ntawm kev tswj qhov hnyav molecular, qib ntawm kev hloov pauv, thiab cov xwm txheej ntawm kev daws teeb meem ntawm HPMC, nws cov viscosity tuaj yeem hloov kho kom tau raws li cov kev xav tau ntawm kev siv sib txawv. Yav tom ntej, kev tshawb fawb tob txog kev sib raug zoo ntawm HPMC cov qauv molecular thiab viscosity yuav pab tsim cov khoom HPMC nrog kev ua tau zoo dua thiab nthuav dav nws cov teb thov.
Lub sijhawm tshaj tawm: Lub Xya Hli-20-2024