Cellulose ether yog ib chav kawm tseem ceeb ntawm cov tshuaj polymer, siv dav hauv kev tsim kho, tshuaj, khoom noj thiab lwm yam teb. Ntawm lawv, HPMC (hydroxypropyl methylcellulose), MC (methylcellulose), HEC (hydroxyethyl cellulose) thiab CMC (carboxymethyl cellulose) yog plaub hom cellulose ethers.
Methyl cellulose (MC):
MC yaj tau hauv dej txias thiab nyuaj rau yaj hauv dej kub. Cov kua dej ruaj khov heev hauv pH = 3 ~ 12, muaj kev sib raug zoo, thiab tuaj yeem sib xyaw nrog ntau yam surfactants xws li hmoov txhuv nplej siab thiab guar gum. Thaum qhov kub ncav cuag qhov kub gelation, gelation tshwm sim.
Qhov kev khaws dej ntawm MC nyob ntawm nws cov nqi ntxiv, viscosity, particle fineness thiab dissolving rate. Feem ntau, qhov kev khaws dej yog siab thaum qhov ntau ntxiv, cov khoom me me thiab viscosity siab. Ntawm lawv, qhov kev ntxiv muaj qhov cuam tshuam loj tshaj plaws rau qhov kev khaws dej, thiab qib viscosity tsis sib npaug rau qhov kev khaws dej. Qhov kev yaj feem ntau nyob ntawm qib kev hloov pauv ntawm qhov chaw thiab qhov fineness ntawm cov khoom cellulose.
Kev hloov pauv kub yuav cuam tshuam loj heev rau qhov khaws dej ntawm MC. Feem ntau, qhov kub siab dua, qhov khaws dej yuav phem dua. Yog tias qhov kub ntawm cov mortar tshaj 40 ° C, qhov khaws dej ntawm MC yuav txo qis heev, cuam tshuam loj heev rau kev ua haujlwm ntawm cov mortar.
MC muaj feem cuam tshuam loj heev rau kev ua haujlwm ntawm kev tsim kho thiab kev nplaum ntawm cov mortar. Ntawm no, "kev nplaum" txhais tau hais tias kev nplaum ntawm cov cuab yeej siv hauv kev tsim kho thiab cov khoom siv phab ntsa, uas yog, qhov kev tiv thaiv shear ntawm cov mortar. Qhov kev nplaum ntau dua, qhov kev tiv thaiv shear ntawm cov mortar ntau dua, qhov kev siv zog ntau dua los ntawm tus neeg ua haujlwm thaum siv, thiab kev ua haujlwm tsis zoo ntawm cov mortar. Qhov kev nplaum ntawm MC yog nyob rau theem nruab nrab ntawm cov khoom cellulose ether.
Hydroxypropyl methylcellulose (HPMC):
HPMC yooj yim yaj hauv dej, tab sis tej zaum yuav nyuaj rau yaj hauv dej kub. Txawm li cas los xij, nws qhov kub gelation hauv dej kub siab dua li ntawm MC, thiab nws qhov solubility hauv dej txias kuj zoo dua li ntawm MC.
Qhov viscosity ntawm HPMC muaj feem cuam tshuam nrog qhov hnyav molecular, thiab qhov viscosity siab thaum qhov hnyav molecular loj. Kub kuj cuam tshuam rau nws qhov viscosity, thiab qhov viscosity txo qis thaum qhov kub nce, tab sis qhov kub uas nws qhov viscosity txo qis qis dua li ntawm MC. Nws cov tshuaj ruaj khov ntawm chav tsev kub.
Qhov kev khaws dej ntawm HPMC nyob ntawm qhov ntxiv thiab viscosity, thiab lwm yam. Qhov kev khaws dej ntawm tib qhov ntxiv yog siab dua li ntawm MC.
HPMC ruaj khov rau cov kua qaub thiab alkalis, thiab nws cov kua dej ruaj khov heev hauv pH ntau ntawm 2 ~ 12. Caustic soda thiab dej txiv qaub tsis muaj feem cuam tshuam rau nws cov kev ua tau zoo, tab sis alkali tuaj yeem ua kom nws cov nqi yaj sai dua thiab ua rau viscosity nce. HPMC ruaj khov rau cov ntsev dav dav, tab sis thaum qhov concentration ntawm cov ntsev daws siab, qhov viscosity ntawm HPMC kua feem ntau nce.
HPMC tuaj yeem sib xyaw nrog cov tshuaj polymer uas yaj tau hauv dej los tsim cov tshuaj sib xws, viscosity siab dua, xws li polyvinyl cawv, starch ether, zaub gum, thiab lwm yam.
HPMC muaj kev tiv thaiv enzyme zoo dua li MC, thiab nws cov kua tsis tshua muaj kev cuam tshuam rau kev puas tsuaj ntawm enzymatic dua li MC. HPMC muaj kev nplaum zoo dua rau mortar dua li MC.
Hydroxyethyl cellulose (HEC):
HEC yaj tau hauv dej txias thiab nyuaj rau yaj hauv dej kub. Cov tshuaj no ruaj khov thaum kub siab thiab tsis muaj cov khoom gel. Nws siv tau ntev hauv mortar ntawm kub siab, tab sis nws cov dej khaws cia qis dua MC.
HEC ruaj khov rau cov kua qaub thiab alkalis dav dav, alkali tuaj yeem ua kom nws cov yaj sai dua thiab ua rau viscosity me ntsis, thiab nws cov dispersibility hauv dej qis dua MC thiab HPMC me ntsis.
HEC muaj kev ua tau zoo ntawm kev ncua rau cov mortar, tab sis cov cement muaj lub sijhawm ncua ntev dua.
HEC tsim los ntawm qee lub tuam txhab hauv tsev muaj kev ua tau zoo qis dua MC vim nws cov dej ntau thiab cov tshauv ntau.
Carboxymethyl cellulose (CMC):
CMC yog ib qho ionic cellulose ether uas tau npaj los ntawm ntau yam kev kho mob tom qab cov fibers ntuj (xws li paj rwb) raug kho nrog alkali thiab chloroacetic acid siv ua tus neeg sawv cev etherifying. Qhov degree ntawm kev hloov pauv feem ntau yog nruab nrab ntawm 0.4 thiab 1.4, thiab nws cov kev ua tau zoo cuam tshuam loj heev los ntawm qhov degree ntawm kev hloov pauv.
CMC muaj cov teebmeem thickening thiab emulsification stabilization, thiab tuaj yeem siv rau hauv cov dej haus uas muaj roj thiab protein los ua lub luag haujlwm emulsification stabilization.
CMC muaj cov nyhuv khaws dej. Hauv cov khoom nqaij, qhob cij, ncuav mog qab zib thiab lwm yam khoom noj, nws tuaj yeem ua lub luag haujlwm hauv kev txhim kho cov ntaub so ntswg, thiab tuaj yeem ua rau dej tsis tshua muaj zog, ua rau cov khoom tsim tau ntau dua, thiab ua rau saj zoo dua.
CMC muaj cov nyhuv gelling thiab siv tau los ua jelly thiab jam.
CMC tuaj yeem tsim ib zaj duab xis rau ntawm qhov chaw ntawm cov khoom noj, uas muaj qee yam kev tiv thaiv rau cov txiv hmab txiv ntoo thiab zaub thiab ua kom lub txee ntawm cov txiv hmab txiv ntoo thiab zaub ntev dua.
Cov cellulose ethers no muaj lawv tus kheej cov yam ntxwv thiab thaj chaw siv. Kev xaiv cov khoom tsim nyog yuav tsum tau txiav txim siab raws li cov kev cai thov tshwj xeeb thiab cov xwm txheej ib puag ncig.
Lub sijhawm tshaj tawm: Lub Kaum Hli-29-2024