Hydroxypropyl methylcellulose (HPMC) yog ib qho hluavtaws polymer muab los ntawm cellulose thiab feem ntau yog siv los ua cov thickener, emulsifier, thiab stabilizer hauv ntau yam lag luam xws li khoom noj khoom haus, tshuaj, thiab tshuaj pleev ib ce. HMPC yog hydroxypropylated derivative ntawm methylcellulose (MC), dej-soluble nonionic cellulose ether muaj li ntawm methoxylated thiab hydroxypropylated cellulose units. HMPC yog dav siv los ua ib qho khoom siv hauv cov tshuaj formulations vim nws cov nontoxicity, biocompatibility, thiab biodegradability.
HMPC Chemical Properties:
Cov khoom siv tshuaj lom neeg ntawm HMPC yog vim muaj cov hydroxyl thiab ether pawg hauv nws cov qauv molecular. Cov pab pawg hydroxyl ntawm cellulose tuaj yeem ua haujlwm los ntawm ntau yam tshuaj lom neeg, xws li etherification, esterification, thiab oxidation, los qhia cov pab pawg sib txawv rau hauv cov pob txha polymer. HMPC muaj ob pawg methoxy (-OCH3) thiab hydroxypropyl (-OCH2CHOHCH3) pawg, uas tuaj yeem tswj tau los muab cov khoom sib txawv xws li solubility, viscosity thiab gelation.
HMPC yog heev soluble nyob rau hauv dej, tsim ntshiab, viscous daws ntawm tsawg concentrations. Lub viscosity ntawm HMPC cov kev daws teeb meem tuaj yeem hloov kho los ntawm kev hloov kho qib ntawm kev hloov pauv (DS) ntawm pawg hydroxypropyl, uas txiav txim siab tus naj npawb ntawm cov chaw hloov pauv hydroxyl ib chav tsev piam thaj. Qhov siab dua DS, qhov qis dua qhov solubility thiab siab dua qhov viscosity ntawm HMPC tov. Cov cuab yeej no tuaj yeem siv los tswj kev tso tawm cov khoom xyaw nquag los ntawm cov tshuaj formulations.
HMPC kuj nthuav tawm tus cwj pwm pseudoplastic, txhais tau hais tias qhov viscosity txo qis nrog nce shear npaum li cas. Cov cuab yeej no ua rau nws haum raws li cov thickener rau cov kua formulations uas yuav tsum tau tiv thaiv shear rog thaum ua los yog daim ntawv thov.
HMPC yog thermally ruaj khov mus txog qhov kub thiab txias, saum toj no uas nws pib degrade. Qhov kub degradation ntawm HMPC nyob ntawm DS thiab qhov concentration ntawm cov polymer hauv cov tshuaj. Qhov kub degradation ntawm HMPC tau tshaj tawm tias yog 190-330 ° C.
Synthesis of HMPC:
HMPC yog synthesized los ntawm etherification cov tshuaj tiv thaiv cellulose nrog propylene oxide thiab methylethylene oxide nyob rau hauv lub xub ntiag ntawm ib tug alkaline catalyst. Cov tshuaj tiv thaiv tshwm sim nyob rau hauv ob kauj ruam: ua ntej, pawg methyl cellulose yog hloov los ntawm propylene oxide, thiab ces cov hydroxyl pawg yog ntxiv hloov los ntawm methyl ethylene oxide. Lub DS ntawm HMPC tuaj yeem tswj tau los ntawm kev kho cov molar piv ntawm propylene oxide rau cellulose thaum lub sij hawm txheej txheem synthesis.
Cov tshuaj tiv thaiv feem ntau yog nqa tawm hauv qhov nruab nrab aqueous ntawm qhov kub thiab siab siab. Lub hauv paus catalyst feem ntau yog sodium los yog potassium hydroxide, uas txhim kho cov reactivity ntawm cellulose hydroxyl pawg mus rau epoxide rings ntawm propylene oxide thiab methylethylene oxide. Cov khoom siv tshuaj tiv thaiv yog tom qab ntawd neutralized, ntxuav thiab qhuav kom tau txais HMPC khoom kawg.
HMPC kuj tseem tuaj yeem ua ke los ntawm reacting cellulose nrog propylene oxide thiab epichlorohydrin nyob rau hauv muaj cov kua qaub catalysts. Txoj kev no, hu ua cov txheej txheem epichlorohydrin, yog siv los tsim cov cationic cellulose derivatives, uas tau them zoo vim muaj cov pab pawg quaternary ammonium.
nyob rau hauv xaus:
HMPC yog cov khoom siv ntau yam polymer nrog cov khoom siv tshuaj zoo heev tsim nyog rau ntau yam kev siv hauv kev lag luam sib txawv. Lub synthesis ntawm HMPC suav nrog cov tshuaj tiv thaiv etherification ntawm cellulose nrog propylene oxide thiab methylethylene oxide nyob rau hauv lub xub ntiag ntawm alkaline catalyst los yog acidic catalyst. Cov khoom ntawm HMPC tuaj yeem hloov kho los ntawm kev tswj cov DS thiab cov concentration ntawm cov polymer. Kev nyab xeeb thiab biocompatibility ntawm HMPC ua rau nws muaj kev xaiv zoo rau cov tshuaj formulations.
Post lub sij hawm: Sep-18-2023