Focus on Cellulose ethers

Kemikari zvivakwa uye synthesis yehydroxypropyl methylcellulose (HMPC)

Hydroxypropyl methylcellulose (HPMC) ipolymer yakagadzirwa kubva muselulosi uye inowanzoshandiswa seyakakora, emulsifier, uye stabilizer mumaindasitiri akasiyana sechikafu, mishonga, uye cosmetics. HMPC inonzi hydroxypropylated derivative yemethylcellulose (MC), mvura-inonyungudika nonionic cellulose ether inoumbwa ne methoxylated uye hydroxypropylated cellulose units. HMPC inoshandiswa zvakanyanya sechinhu chinobatsira mukugadzirwa kwemishonga nekuda kwekusava nehuturu, biocompatibility, uye biodegradability.

HMPC makemikari zvivakwa:

Iyo kemikari zvimiro zveHMPC inofungidzirwa kuvepo kwehydroxyl nemapoka ether mune yayo molecular chimiro. Iwo mapoka ehydroxyl e cellulose anogona kushandiswa kuburikidza neakasiyana makemikari maitiro, senge etherification, esterification, uye oxidation, kuunza akasiyana anoshanda mapoka mu polymer musana. HMPC ine ese methoxy (-OCH3) uye hydroxypropyl (-OCH2CHOHCH3) mapoka, ayo anogona kudzorwa kuti ape akasiyana zvivakwa zvakaita solubility, viscosity uye gelation.

HMPC inonyungudika zvakanyanya mumvura, ichigadzira yakajeka, viscous mhinduro pane yakaderera concentration. Iyo viscosity yeHMPC mhinduro inogona kuchinjwa nekugadzirisa dhigirii rekutsinhanisa (DS) yemapoka e-hydroxypropyl, iyo inosarudza nhamba yenzvimbo dzakagadziridzwa dzehydroxyl pane glucose unit. Iyo yakakwirira yeDS, iyo inodzika iyo solubility uye yakakwirira viscosity yeHMPC mhinduro. Ichi chivakwa chinogona kushandiswa kudzora kuburitswa kwezvinhu zvinoshanda kubva kumishonga yekugadzira mishonga.

HMPC inoratidzawo pseudoplastic maitiro, zvichireva kuti viscosity inodzikira nekuwedzera shear rate. Ichi chivakwa chinoita kuti ive yakakodzera seyakakora kune yemvura magadzirirwo ayo anoda kumirisana neshear masimba panguva yekugadzirisa kana maapplication.

HMPC yakagadzikana nekushisa kusvika kune imwe tembiricha, pamusoro payo inotanga kuderera. Kudzikira tembiricha yeHMPC kunoenderana neDS uye kuwanda kwepolymer mune mhinduro. The degradation tembiricha range yeHMPC inonzi i190-330°C.

Synthesis yeHMPC:

HMPC inogadzirwa ne etherification reaction ye cellulose ine propylene oxide uye methylethylene oxide pamberi pe alkaline catalyst. Mhedzisiro yacho inoenderera mumatanho maviri: kutanga, mapoka emethyl e cellulose anotsiviwa nepropylene oxide, uye ipapo mapoka ehydroxyl anotsiviwa nemethyl ethylene oxide. Iyo DS yeHMPC inogona kudzorwa nekugadzirisa iyo molar ratio yepropylene oxide kune cellulose panguva yekubatanidza maitiro.

Mhedzisiro yacho inowanzoitwa mumvura ine mvura ine tembiricha yakakwira uye kudzvanywa. Iyo yekutanga catalyst inowanzo sodium kana potassium hydroxide, iyo inosimudzira reactivity ye cellulose hydroxyl mapoka akananga epoxide mhete dzepropylene oxide uye methylethylene oxide. Chigadzirwa chinoitwa chinozosarudzika, kugezwa uye kuomeswa kuti uwane yekupedzisira HMPC chigadzirwa.

HMPC inogona zvakare kugadzirwa nekuita cellulose nepropylene oxide uye epichlorohydrin pamberi peadhi catalysts. Iyi nzira, inozivikanwa se epichlorohydrin process, inoshandiswa kugadzira cationic cellulose derivatives, iyo inobhadhariswa zvakanaka nekuda kwekuvapo kwequaternary ammonium mapoka.

mukupedzisa:

HMPC i polymer inoshanda yakawanda ine yakanakisa makemikari zvivakwa zvakakodzera kune akasiyana maapplication mumaindasitiri akasiyana. Kugadzirwa kweHMPC kunosanganisira etherification reaction ye cellulose nepropylene oxide uye methylethylene oxide pamberi pe alkaline catalyst kana acidic catalyst. Izvo zvimiro zveHMPC zvinogona kugadziridzwa nekudzora iyo DS uye kusungwa kwepolymer. Kuchengetedzeka uye biocompatibility yeHMPC inoita kuti ive sarudzo yakanaka yekugadzira mishonga.


Nguva yekutumira: Sep-18-2023
WhatsApp Online Chat !