Hydroxypropyl Methylcellulose (HPMC) yog ib qho tseem ceeb ntawm cellulose ether derivative uas tau siv dav hauv ntau qhov chaw lag luam vim nws lub cev thiab tshuaj lom neeg tshwj xeeb.Nws cov khoom viscosity yog ib qho tseem ceeb tshaj plaws ntawm HPMC, cuam tshuam ncaj qha rau nws cov kev ua tau zoo hauv ntau daim ntawv thov.
1. Cov khoom tseem ceeb ntawm HPMC
HPMC yog nonnionic cellulose ether tau los ntawm kev hloov ib feem ntawm hydroxyl pawg (–OH) hauv cellulose molecule nrog methoxy pawg (–OCH3) thiab hydroxypropyl pawg (–OCH2CH(OH)CH3).Nws muaj zoo solubility nyob rau hauv dej thiab ib co organic solvents, tsim pob tshab colloidal daws.Lub viscosity ntawm HPMC feem ntau yog txiav txim siab los ntawm nws qhov hnyav molecular, degree ntawm kev hloov pauv (DS, Degree of Hloov) thiab hloov pauv.
2. Kev txiav txim siab ntawm viscosity ntawm HPMC
Lub viscosity ntawm HPMC cov kev daws teeb meem feem ntau yog ntsuas los ntawm kev siv lub viscometer rotational lossis capillary viscometer.Thaum ntsuas, yuav tsum tau them nyiaj mloog mus rau qhov concentration, kub thiab shear tus nqi ntawm cov tshuaj, vim hais tias cov yam ntxwv no muaj peev xwm cuam tshuam rau tus nqi viscosity.
Kev daws teeb meem: Lub viscosity ntawm HPMC nce nrog qhov nce ntawm cov tshuaj concentration.Thaum cov concentration ntawm HPMC cov tshuaj txo qis, kev sib cuam tshuam ntawm cov molecules tsis muaj zog thiab cov viscosity qis dua.Raws li qhov concentration nce, qhov entanglement thiab kev sib cuam tshuam ntawm molecules nce, ua rau muaj kev nce ntxiv hauv viscosity.
Kub: Lub viscosity ntawm HPMC cov kev daws teeb meem yog rhiab heev rau qhov kub thiab txias.Feem ntau, raws li qhov kub thiab txias, qhov viscosity ntawm HPMC cov tshuaj yuav txo.Qhov no yog vim qhov kub thiab txias ua rau kom muaj zog molecular zog thiab tsis muaj zog intermolecular kev cuam tshuam.Nws yuav tsum raug sau tseg tias HPMC nrog ntau qib kev hloov pauv thiab qhov hnyav molecular muaj qhov sib txawv ntawm qhov kub thiab txias.
Shear npaum li cas: HPMC cov kev daws teeb meem pom pseudoplastic (shear thinning) tus cwj pwm, piv txwv li cov viscosity siab dua ntawm qhov qis shear thiab txo qis ntawm cov shear siab.Qhov kev coj cwj pwm no yog vim lub zog shear uas ua raws cov saw hlau molecular raws cov kev taw qhia shear, yog li txo cov entanglements thiab kev cuam tshuam ntawm cov molecules.
3. Cov yam ntxwv cuam tshuam rau HPMC viscosity
Molecular Luj: Qhov hnyav molecular ntawm HPMC yog ib qho tseem ceeb uas txiav txim siab nws cov viscosity.Feem ntau hais lus, qhov loj dua qhov hnyav molecular, qhov siab dua qhov viscosity ntawm cov tshuaj.Qhov no yog vim HPMC cov molecules uas muaj qhov hnyav molecular ntau dua yuav tsim cov kev sib txuas sib txuas, yog li ua rau muaj kev sib txhuam sab hauv ntawm cov tshuaj.
Qib ntawm kev hloov pauv thiab hloov pauv: Tus lej thiab kev faib tawm ntawm methoxy thiab hydroxypropyl substituents hauv HPMC kuj cuam tshuam rau nws cov viscosity.Feem ntau, qhov siab dua qib ntawm methoxy hloov pauv (DS), qhov qis dua qhov viscosity ntawm HPMC, vim hais tias qhov kev taw qhia ntawm methoxy substituents yuav txo cov hydrogen bonding quab yuam ntawm molecules.Kev taw qhia ntawm hydroxypropyl substituents yuav ua rau kom muaj kev sib cuam tshuam hauv nruab nrab, yog li ua kom viscosity.Tsis tas li ntawd, kev faib cov khoom sib txawv ntawm cov khoom sib txawv pab tsim kom muaj kev ruaj khov thiab ua kom cov viscosity ntawm cov tshuaj.
pH tus nqi ntawm cov tshuaj: Txawm hais tias HPMC yog non-ionic polymer thiab nws cov viscosity tsis rhiab rau cov kev hloov pauv ntawm pH tus nqi ntawm cov tshuaj, cov pH siab heev ( acidic heev lossis alkaline heev ) tuaj yeem ua rau degradation ntawm cov qauv molecular. HPMC, yog li cuam tshuam rau viscosity.
4. Daim ntawv thov teb ntawm HPMC
Vim nws cov viscosity zoo heev, HPMC tau siv dav hauv ntau qhov chaw:
Cov ntaub ntawv hauv tsev: Hauv cov khoom siv hauv tsev, HPMC yog siv los ua cov thickener thiab dej tuav tus neeg sawv cev los txhim kho kev tsim kho thiab ua kom muaj kev sib tsoo.
Kev lag luam kws tshuaj: Hauv kev lag luam kws tshuaj, HPMC yog siv los ua cov ntawv khi rau cov ntsiav tshuaj, tus neeg ua yeeb yaj kiab tsim rau cov tshuaj ntsiav thiab cov khoom thauj rau cov tshuaj tiv thaiv kev tso tawm.
Kev lag luam khoom noj khoom haus: HPMC yog siv los ua cov thickener thiab stabilizer hauv kev lag luam khoom noj rau kev tsim cov ice cream, jelly thiab khoom noj siv mis.
Cov khoom siv tshuaj lom neeg txhua hnub: Hauv cov khoom siv tshuaj txhua hnub, HPMC yog siv los ua cov thickener 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 cov kev ua tau zoo hauv ntau yam kev siv.Los ntawm kev tswj hwm qhov hnyav molecular, qib kev hloov pauv, thiab kev daws teeb meem ntawm HPMC, nws cov viscosity tuaj yeem hloov kho kom tau raws li cov kev xav tau sib txawv.Nyob rau yav tom ntej, kev tshawb fawb tob txog kev sib raug zoo ntawm HPMC cov qauv molecular thiab viscosity yuav pab tsim HPMC cov khoom lag luam nrog kev ua tau zoo dua thiab nthuav dav nws daim ntawv thov.
Post lub sij hawm: Lub Xya hli ntuj-20-2024