MC ndi methyl cellulose, yomwe imapangidwa ndi cellulose ether pochiza thonje loyengedwa ndi alkali, pogwiritsa ntchito methane chloride ngati etherification, ndikudutsa muzochitika zingapo. Kawirikawiri, mlingo wa kusintha ndi 1.6 ~ 2.0, ndipo kusungunuka kumasiyananso ndi madigiri osiyanasiyana a kusintha. Ndi ya non-ionic cellulose ether.
(1) Kusunga madzi kwa methyl cellulose kumadalira kuchuluka kwake kowonjezera, kukhuthala, kusalala kwa tinthu tating'onoting'ono ndi kuchuluka kwa kusungunuka. Kawirikawiri, ngati kuchuluka kowonjezera kuli kwakukulu, kusalala kwake kuli kochepa, ndipo kukhuthala kwake kuli kwakukulu, kuchuluka kwa kusungunuka kwa madzi kumakhala kwakukulu. Pakati pawo, kuchuluka kwa kuwonjezeredwa kumakhudza kwambiri kuchuluka kwa kusungunuka kwa madzi, ndipo kuchuluka kwa kukhuthala sikufanana mwachindunji ndi kuchuluka kwa kusungunuka kwa madzi. Kusungunuka kwa madzi kumadalira makamaka kuchuluka kwa kusintha kwa pamwamba pa tinthu tating'onoting'ono ta cellulose ndi kusalala kwa tinthu tating'onoting'ono. Pakati pa ma cellulose ether omwe ali pamwambapa, methyl cellulose ndi hydroxypropyl methyl cellulose zili ndi kuchuluka kwa kusungunuka kwa madzi.
(2) Methylcellulose imasungunuka m'madzi ozizira, ndipo zimakhala zovuta kusungunuka m'madzi otentha. Madzi ake amadzi ndi okhazikika kwambiri pa pH = 3 ~ 12. Imagwirizana bwino ndi starch, guar gum, ndi zina zotero. Kutentha kukafika pa kutentha kwa gelation, gelation imachitika.
(3) Kusintha kwa kutentha kudzakhudza kwambiri kuchuluka kwa madzi omwe amasungidwa mu methyl cellulose. Nthawi zambiri, kutentha kukakhala kwakukulu, madzi omwe amasungidwa amakhala oipa kwambiri. Ngati kutentha kwa matope kupitirira 40°C, madzi omwe amasungidwa mu methyl cellulose adzachepa kwambiri, zomwe zidzakhudza kwambiri kapangidwe ka matopewo.
(4) Methyl cellulose imakhudza kwambiri kapangidwe ndi kumatirira kwa matope. "Kumatirira" apa kumatanthauza mphamvu yomatirira yomwe imamveka pakati pa chida chogwiritsira ntchito cha wantchito ndi khoma, ndiko kuti, kukana kukatira kwa matope. Kumatirira kwake ndi kwakukulu, kukana kukatira kwa matope ndi kwakukulu, ndipo mphamvu zomwe ogwira ntchito amafunikira pakugwiritsa ntchito matope ndi zazikulu, ndipo magwiridwe antchito a matope ndi otsika. Kumatirira kwa methyl cellulose kuli pamlingo wocheperako muzinthu zopangidwa ndi cellulose ether.
HPMC ndi hydroxypropyl methylcellulose, yomwe ndi ether yosakanikirana ya cellulose yopangidwa kuchokera ku thonje loyengedwa pambuyo pa alkalization, pogwiritsa ntchito propylene oxide ndi methyl chloride ngati zinthu zoyeretsera, komanso kudzera muzochita zingapo. Mlingo wa kusintha nthawi zambiri umakhala 1.2 ~ 2.0. Katundu wake ndi wosiyana chifukwa cha kusiyana kwa kuchuluka kwa methoxyl ndi kuchuluka kwa hydroxypropyl.
(1) Hydroxypropyl methylcellulose imasungunuka mosavuta m'madzi ozizira, ndipo imakumana ndi zovuta kusungunuka m'madzi otentha. Koma kutentha kwake kwa gelation m'madzi otentha ndi kwakukulu kwambiri kuposa kwa methyl cellulose. Kusungunuka m'madzi ozizira nakonso kumawonjezeka kwambiri poyerekeza ndi methyl cellulose.
(2) Kukhuthala kwa hydroxypropyl methylcellulose kumagwirizana ndi kulemera kwake kwa mamolekyulu, ndipo kulemera kwa mamolekyulu kukakhala kwakukulu, kukhuthala kumakhala kwakukulu. Kutentha kumakhudzanso kukhuthala kwake, pamene kutentha kukukwera, kukhuthala kumachepa. Komabe, kukhuthala kwake kwakukulu kumakhala ndi kutentha kochepa kuposa methyl cellulose. Yankho lake ndi lokhazikika likasungidwa kutentha kwa chipinda.
(3) Hydroxypropyl methylcellulose ndi yokhazikika ku asidi ndi alkali, ndipo yankho lake lamadzi ndi lokhazikika kwambiri pa pH = 2 ~ 12. Madzi a Caustic soda ndi laimu sakhudza kwambiri magwiridwe ake, koma alkali imatha kufulumizitsa kusungunuka kwake ndikuwonjezera kukhuthala kwake. Hydroxypropyl methylcellulose ndi yokhazikika ku mchere wamba, koma pamene kuchuluka kwa mchere kuli kwakukulu, kukhuthala kwa yankho la hydroxypropyl methylcellulose kumawonjezeka.
(4) Kusunga madzi kwa hydroxypropyl methylcellulose kumadalira kuchuluka kwake kowonjezera, kukhuthala, ndi zina zotero, ndipo kuchuluka kwake kosungira madzi pansi pa kuchuluka komweko kowonjezera kumakhala kwakukulu kuposa kwa methyl cellulose.
(5) Hydroxypropyl methylcellulose ikhoza kusakanikirana ndi mankhwala a polymer osungunuka m'madzi kuti apange yankho lofanana komanso lokhuthala kwambiri. Monga polyvinyl alcohol, starch ether, vegetable gum, ndi zina zotero.
(6) Kugwirizana kwa hydroxypropyl methylcellulose ku matope opangidwa ndi matope n'kokwera kuposa kwa methylcellulose.
(7) Hydroxypropyl methylcellulose ili ndi kukana bwino kwa ma enzyme kuposa methylcellulose, ndipo yankho lake silingathe kuwonongeka ndi ma enzyme kuposa methylcellulose.
Nthawi yotumizira: Epulo-17-2023