Hydroxypropyl methylcellulose (HPMC)yog ib qho tseem ceeb nonionic cellulose ether siv dav hauv kev tsim kho, tshuaj, khoom noj, thiab cov tshuaj txhua hnub. Viscosity yog qhov qhia tseem ceeb rau kev ntsuam xyuas qhov zoo thiab kev siv tau ntawm HPMC. Nws tsis yog tsuas yog qhia txog cov khoom rheological ntawm nws cov tshuaj tab sis kuj muaj feem cuam tshuam ncaj qha rau nws cov thickening, dej khaws cia, thiab zaj duab xis-tsim cov khoom. Txhawm rau kom ntseeg tau tias cov khoom zoo sib xws, kev ntsuas viscosity yuav tsum tau ua tiav siv txoj kev ntsuas viscosity scientific thiab standardized.
1. Txoj Cai Xeem
HPMC yaj hauv dej los ua cov kua pob tshab lossis pob tshab. Nws cov viscosity nyob ntawm qib polymerization, qib hloov pauv, thiab kev sib xyaw ntawm cov kua. Kev kuaj viscosity piav qhia txog cov yam ntxwv ntws ntawm cov kua HPMC los ntawm kev ntsuas qhov sib txhuam sab hauv ntawm cov kua thaum ntws ntawm qhov kub tshwj xeeb. Kev ntsuas feem ntau yog ua tiav siv lub tshuab ntsuas viscometer tig (Brookfield hom) lossis lub tshuab ntsuas viscometer capillary. Txoj kev tig feem ntau siv, vim nws muab kev nkag siab zoo dua ntawm cov khoom shear-thinning ntawm cov kua ntawm qhov ceev sib txawv.
2. Cov Qauv Sib Xws thiab Cov Kev Cai Xeem
Tam sim no, kev kuaj HPMC viscosity feem ntau yog raws li cov hauv qab no:
Tus Txheej Txheem Suav: GB/T 12000 "Cov Txheej Txheem Xeem Dav Dav rau Cellulose Ethers"
Tus Qauv Tebchaws Meskas: ASTM D1347 "Cov Txheej Txheem Ntsuas Txheem rau Cellulose Ether Solutions"
Kev siv hauv kev lag luam: Viscosity yog ntsuas los ntawm kev siv 2% aqueous solution ntawm 20°C siv Brookfield rotational viscometer.
Qhov kev ntsuas qhov concentration ntawm cov tshuaj feem ntau yog 2% (feem pua ntawm pawg), tab sis cov qib HPMC sib txawv kuj tseem yuav xav tau kev ntsuas ntawm 1%, 2%, lossis ntau dua. Qhov kub ntawm kev ntsuas yuav tsum tau tswj hwm nruj me ntsis ntawm 20 ± 0.1 ° C, vim tias qhov kub thiab txias hloov pauv tuaj yeem cuam tshuam rau qhov nyeem viscosity.
3. Cov Txheej Txheem Sim
3.1. Kev Npaj Tshuaj Reagent thiab Cov Cuab Yeej
Kev ntsuas qhov tseeb (0.1 mg qhov tseeb)
Brookfield rotational viscometer (feem ntau muaj LV series)
3.2. Da dej kub tas li lossis ib puag ncig uas tswj tau qhov kub
Dej huv (ua tau raws li GB/T 6682 Qib III cov cai dej)
Ntxuav lub beaker thiab lub stirrer
3.3. Kev Npaj Cov Tshuaj
Ntsuas qhov hnyav kom raug 2.00 g (± 0.01 g) ntawm cov qauv HPMC.
Muab kwv yees li 80% ntawm lub hom phiaj ntim dej huv (kwv yees li 80 mL) rau hauv lub beaker thiab cua sov txog li 80 ° C. Maj mam thiab sib npaug zos sprinkle HPMC rau hauv lub beaker thaum do kom tsis txhob clumping.
Txuas ntxiv do kom txog thaum HPMC ntub tag thiab tawg. Tom qab ntawd, ntxiv cov dej txias seem thiab txias rau qhov kub thiab txias, coj tag nrho cov ntim mus rau 100 mL.
Tso cov tshuaj no rau hauv lub tub yees ntawm 4°C ib hmos ib hmos kom nws o tag thiab tshem tawm cov npuas cua.
3.4. Kev Ntsuas Qhov Viscosity
Muab cov tshuaj no tso rau hauv lub dab dej uas muaj qhov kub thiab txias tas li, thiab tswj qhov kub ntawm 20 ± 0.1°C. Xaiv lub spindle uas tsim nyog (feem ntau yog No. 2 lossis No. 3) thiab qhov ceev (feem ntau yog 30 rpm).
Pib lub viscometer thiab sau cov ntawv nyeem tom qab lub koob ruaj khov. Rov ua txhua qhov kev ntsuas peb zaug, thiab coj qhov nruab nrab ua qhov tshwm sim kawg.
Yog tias qhov nyeem ntawv tshaj qhov ntsuas ntawm lub cuab yeej, hloov lub spindle lossis kho qhov concentration thiab rov ntsuas dua.
4. Kev ceev faj
Kev tswj qhov kub thiab txias yog qhov tseem ceeb heev. Rau txhua qhov kub nce 1°C, qhov viscosity yuav txo qis li ntawm 2% txog 3%.
Cov tshuaj yuav tsum yaj tag nrho thiab tsis muaj npuas, txwv tsis pub qhov nyeem ntawv yuav qis lossis hloov pauv.
HPMC ua rau pom cov khoom ua kom nyias nyias, yog li qhov ceev thiab lub sijhawm ntsuas yuav tsum tau tswj hwm tas li.
Cov dej siv yuav tsum tsis muaj cov khoom tsis huv thiab cov ions kom tsis txhob cuam tshuam rau kev yaj thiab kev nyeem ntawv.
Cov cuab yeej yuav tsum tau calibrated tsis tu ncua, thiab lub spindle thiab lub thawv kuaj yuav tsum tau khaws cia kom huv.
5. Kev Tshawb Fawb Txog Cov Yam Uas Muaj Feem Cuam Tshuam
Qib ntawm Polymerization thiab Qib ntawm Kev Hloov Chaw: Qhov siab dua qib ntawm polymerization ntawm HPMC, qhov ntev dua ntawm cov saw hlau molecular thiab qhov ntau dua qhov viscosity ntawm cov tshuaj. Qib ntawm methoxy thiab hydroxypropoxy hloov chaw kuj cuam tshuam rau nws cov hydrophilicity thiab cov qauv ntawm cov tshuaj.
Kev Ntsuas: Kev ntsuas qhov concentration thiab viscosity ntawm cov tshuaj muaj feem cuam tshuam nrog exponentially, thiab txawm tias qhov kev hloov pauv me me hauv kev ntsuas kuj tuaj yeem cuam tshuam rau cov txiaj ntsig ntawm kev sim. Kub thiab pH: Kev nce qhov kub thiab txias ua rau viscosity txo qis, thaum kev hloov pauv pH feem ntau muaj qhov cuam tshuam me ntsis rau HPMC viscosity vim tias nws yog cov cellulose ether nonionic.
Kev Laus ntawm Cov Tshuaj: Qhov viscosity yuav maj mam txo qis tom qab khaws cia ntev. Nws raug pom zoo kom ua tiav qhov kev sim hauv 24 teev tom qab npaj.
6. Kev Nthuav Qhia Txog Cov Txiaj Ntsig thiab Daim Ntawv Thov
Cov txiaj ntsig ntawm kev sim tau qhia ua mPa·s (milliPascals·seconds), piv txwv li, "2% tshuaj, 20°C, 20,000 mPa·s." Hauv kev siv hauv kev lag luam,HPMCCov qib viscosity feem ntau yog qhia ua txhiab feem, xws li 400 cps thiab 20,000 cps. Cov neeg siv tuaj yeem xaiv cov qib sib txawv raws li qhov xav tau ntawm daim ntawv thov thiab kev tsim cov qauv.
Lub sijhawm tshaj tawm: Lub Xya Hli-30-2025