Focus on Cellulose ethers

Lintho tsa lik'hemik'hale le motsoako oa hydroxypropyl methylcellulose (HMPC)

Hydroxypropyl methylcellulose (HPMC) ke polymer ea maiketsetso e nkiloeng ho selulose 'me hangata e sebelisoa e le setenya, emulsifier, le stabilizer liindasteri tse fapaneng tse kang lijo, meriana le litlolo. HMPC ke hydroxypropylated derivative of methylcellulose (MC), ether e qhibilihang ka metsing e nonionic cellulose e entsoeng ka likarolo tsa methoxylated le hydroxypropylated cellulose. HMPC e sebelisoa haholo joalo ka mothusi mefuteng ea meriana ka lebaka la ho se chefo, ho lumellana ha eona le ho senyeha ha eona.

Lintho tsa lik'hemik'hale tsa HMPC:

Lintho tsa lik'hemik'hale tsa HMPC li hlahisoa ke boteng ba lihlopha tsa hydroxyl le ether ka sebopeho sa eona sa molek'hule. Lihlopha tsa hydroxyl tsa selulose li ka sebelisoa ka karabelo e fapaneng ea lik'hemik'hale, joalo ka etherification, esterification, le oxidation, ho hlahisa lihlopha tse fapaneng tse sebetsang mokokotlong oa polymer. HMPC e na le lihlopha tse peli tsa methoxy (-OCH3) le hydroxypropyl (-OCH2CHOHCH3), tse ka laoloang ho fana ka thepa e fapaneng e kang solubility, viscosity le gelation.

HMPC e qhibiliha haholo ka metsing, e etsa litharollo tse hlakileng, tse nang le viscous maemong a tlase. Viscosity ea tharollo ea HMPC e ka fetoloa ka ho lokisa tekanyo ea ho fetola (DS) ea lihlopha tsa hydroxypropyl, e khethollang palo ea libaka tse fetotsoeng tsa hydroxyl ho unit ea glucose. Ha DS e phahame, e fokotsa ho qhibiliha le ho phahamisa viscosity ea tharollo ea HMPC. Thepa ena e ka sebelisoa ho laola ho lokolloa ha metsoako e sebetsang ho tloha metsoako ea meriana.

HMPC e boetse e bonts'a boits'oaro ba pseudoplastic, ho bolelang hore viscosity e fokotseha ka sekhahla sa ho kuta. Thepa ena e etsa hore e tšoanelehe joalo ka motenya bakeng sa metsoako ea mokelikeli e hlokang ho mamella matla a ho kuta nakong ea ts'ebetso kapa ts'ebeliso.

HMPC e tsitsitse ka mocheso ho fihlela mocheso o itseng, ka holim'a moo e qala ho senyeha. Mocheso oa ho senyeha ha HMPC o itšetlehile ka DS le mahloriso a polymer ka tharollo. Mocheso oa mocheso oa ho senyeha oa HMPC o tlalehoa e le 190-330 ° C.

Tlhaloso ea HMPC:

HMPC e entsoe ke karabelo ea etherification ea selulose e nang le propylene oxide le methylethylene oxide ka boteng ba alkaline catalyst. Karabelo e tsoela pele ka mehato e 'meli: ea pele, lihlopha tsa methyl tsa selulose li nkeloa sebaka ke propylene oxide, ebe lihlopha tsa hydroxyl li nkeloa sebaka ke methyl ethylene oxide. DS ea HMPC e ka laoloa ka ho fetola tekanyo ea molar ea propylene oxide ho cellulose nakong ea ts'ebetso ea ho kopanya.

Karabelo e atisa ho etsoa ka mokhoa o nang le metsi ka mocheso o phahameng le khatello. Ntho ea mantlha hangata ke sodium kapa potassium hydroxide, e ntlafatsang ts'ebetso ea lihlopha tsa cellulose hydroxyl ho ea meheleng ea epoxide ea propylene oxide le methylethylene oxide. Sehlahisoa sa karabelo se felloa ke matla, se hlatsuoa le ho omisoa ho fumana sehlahisoa sa ho qetela sa HMPC.

HMPC e ka boela ea etsoa ka ho arabela selulose ka propylene oxide le epichlorohydrin boteng ba li-catalysts tsa acid. Mokhoa ona, o tsejoang e le ts'ebetso ea epichlorohydrin, o sebelisetsoa ho hlahisa li-derivatives tsa cationic cellulose, tse qosoang hantle ka lebaka la boteng ba lihlopha tsa quaternary ammonium.

ha re phethela:

HMPC ke polymer e sebetsang ka bongata e nang le lisebelisoa tse ntle tsa lik'hemik'hale tse loketseng lits'ebetso tse fapaneng liindastering tse fapaneng. Tšimoloho ea HMPC e kenyelletsa karabelo ea etherification ea selulose e nang le propylene oxide le methylethylene oxide ka boteng ba alkaline catalyst kapa acidic catalyst. Thepa ea HMPC e ka hlophisoa ka ho laola DS le mahloriso a polymer. Tšireletseho le biocompatibility ea HMPC e etsa hore e be khetho e ntle bakeng sa metsoako ea meriana.


Nako ea poso: Sep-18-2023
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