IHydroxypropyl methylcellulose (HPMC) i-polymer yokwenziwa etholakala ku-cellulose futhi ivamise ukusetshenziswa njenge-thickener, emulsifier, kanye ne-stabilizer ezimbonini ezihlukahlukene ezifana nokudla, imithi, kanye nezimonyo. I-HMPC iwumphumela we-hydroxypropylated we-methylcellulose (MC), i-ether ye-nonionic cellulose encibilika emanzini eyakhiwe ngamayunithi e-cellulose e-methoxylated kanye ne-hydroxypropylated. I-HMPC isetshenziswa kabanzi njenge-excipient ekwenziweni kwemithi ngenxa yokungabi nabuthi, i-biocompatibility, kanye ne-biodegradability.
Izakhiwo zamakhemikhali ze-HMPC:
Izici zamakhemikhali ze-HMPC zibangelwa ukuba khona kwamaqembu e-hydroxyl ne-ether esakhiweni sawo samangqamuzana. Amaqembu e-hydroxyl we-cellulose angenziwa asebenze ngokuphendula kwamakhemikhali okuhlukahlukene, njenge-etherification, i-esterification, ne-oxidation, ukwethula amaqembu ahlukene asebenzayo kumgogodla we-polymer. I-HMPC iqukethe kokubili amaqembu e-methoxy (-OCH3) kanye ne-hydroxypropyl (-OCH2CHOHCH3), angalawulwa ukuze anikeze izakhiwo ezihlukene ezifana nokuncibilika, i-viscosity kanye ne-gelation.
I-HMPC incibilika kakhulu emanzini, yakha izixazululo ezicacile, ezine-viscous ezindaweni eziphansi. I-viscosity yezixazululo ze-HMPC ingashintshwa ngokulungisa izinga lokushintsha (DS) lamaqembu e-hydroxypropyl, okunquma inani lezindawo ze-hydroxyl eziguquliwe ngeyunithi ngayinye ye-glucose. Lapho i-DS iphakeme, i-solubility iyancipha futhi iphakamisa i-viscosity yesisombululo se-HMPC. Lesi sakhiwo singasetshenziswa ukulawula ukukhululwa kwezithako ezisebenzayo ekwakhiweni kwemithi.
I-HMPC iphinde ibonise ukuziphatha kwe-pseudoplastic, okusho ukuthi i-viscosity iyancipha ngokukhuphuka kwezinga lokugunda. Lesi sakhiwo siyenza ifaneleke njengokuqina kokwakhiwa koketshezi oludinga ukumelana namandla okugunda ngesikhathi sokucubungula noma ukufakwa.
I-HMPC izinzile ngokushisa ifike kuzinga lokushisa elithile, lapho iqala ukuwohloka ngaphezu kwayo. Izinga lokushisa lokuwohloka kwe-HMPC lincike ku-DS kanye nokugxila kwe-polymer esixazululweni. Izinga lokushisa lokuwohloka le-HMPC libikwa liyi-190-330°C.
Ukuhlanganiswa kwe-HMPC:
I-HMPC ihlanganiswa ukusabela kwe-etherification ye-cellulose nge-propylene oxide ne-methylethylene oxide phambi kwe-catalyst ye-alkali. Ukusabela kuqhubeka ngezinyathelo ezimbili: okokuqala, amaqembu e-methyl e-cellulose athathelwa indawo yi-propylene oxide, bese amaqembu e-hydroxyl aphinde athathelwe indawo yi-methyl ethylene oxide. I-DS ye-HMPC ingalawulwa ngokulungisa isilinganiso se-molar ye-propylene oxide ku-cellulose ngesikhathi senqubo yokuhlanganisa.
Ukusabela ngokuvamile kwenziwa endaweni enamanzi at lokushisa ephakeme kanye nokucindezela. I-catalyst eyisisekelo ngokuvamile i-sodium noma i-potassium hydroxide, ethuthukisa ukusebenza kabusha kwamaqembu e-cellulose hydroxyl emasongweni e-epoxide e-propylene oxide ne-methylethylene oxide. Umkhiqizo wokusabela uyasuswa, ugezwe futhi womiswe ukuze kutholwe umkhiqizo wokugcina we-HMPC.
I-HMPC ingabuye ihlanganiswe ngokusabela i-cellulose nge-propylene oxide ne-epichlorohydrin phambi kwezisusa ze-asidi. Le ndlela, eyaziwa ngokuthi inqubo ye-epichlorohydrin, isetshenziselwa ukukhiqiza okuphuma ku-cationic cellulose, okukhokhiswa kahle ngenxa yokuba khona kwamaqembu e-quaternary ammonium.
Ekuphetheni:
I-HMPC iyi-polymer esebenzayo enezici ezinhle kakhulu zamakhemikhali ezifanele ukusetshenziswa okuhlukahlukene ezimbonini ezahlukahlukene. Ukuhlanganiswa kwe-HMPC kuhilela ukusabela kwe-etherification ye-cellulose nge-propylene oxide ne-methylethylene oxide phambi kwe-alkaline catalyst noma i-acidic catalyst. Izakhiwo ze-HMPC zingashunwa ngokulawula i-DS nokugxila kwe-polymer. Ukuphepha nokuvumelana kwezinto eziphilayo kwe-HMPC kuyenza ibe ukukhetha okuhle ekwenziweni kwemithi.
Isikhathi sokuthumela: Sep-18-2023