Cellulose ether yog cov chav kawm tseem ceeb ntawm cov khoom siv polymer, dav siv hauv kev tsim kho, tshuaj, khoom noj thiab lwm yam. Ntawm lawv, HPMC (hydroxypropyl methylcellulose), MC (methylcellulose), HEC (hydroxyethyl cellulose) thiab CMC (carboxymethyl cellulose) yog plaub hom cellulose ethers.
Methyl cellulose (MC):
MC yog soluble hauv dej txias thiab nyuaj rau yaj hauv dej kub. Cov tshuaj aqueous yog ruaj khov nyob rau hauv thaj tsam ntawm pH = 3 ~ 12, muaj kev sib raug zoo, thiab tuaj yeem tov nrog ntau yam surfactants xws li hmoov txhuv nplej siab thiab guar gum. Thaum qhov kub nce mus txog qhov kub thiab txias, gelation tshwm sim.
Cov dej tuav ntawm MC nyob ntawm nws cov nyiaj ntxiv, viscosity, particle fineness thiab dissolution tus nqi. Feem ntau, cov dej tuav tus nqi yog siab thaum qhov sib ntxiv yog loj, cov khoom zoo thiab cov viscosity siab. Ntawm lawv, qhov sib ntxiv muaj qhov cuam tshuam loj tshaj plaws ntawm cov dej tuav tus nqi, thiab qib viscosity tsis yog proportional rau cov dej tuav tus nqi. Tus nqi dissolution feem ntau yog nyob ntawm qhov kev hloov pauv ntawm qhov chaw thiab qhov zoo ntawm cov cellulose hais.
Kev hloov pauv kub yuav cuam tshuam rau cov dej tuav ntawm MC. Feem ntau, qhov kub thiab txias dua, qhov dej khaws cia tsis zoo. Yog tias qhov ntsuas kub siab tshaj 40 ° C, cov dej tuav ntawm MC yuav txo qis, cuam tshuam rau kev tsim kho ntawm mortar.
MC muaj qhov cuam tshuam loj rau kev tsim kho kev ua haujlwm thiab adhesion ntawm mortar. Ntawm no, "adhesion" yog hais txog qhov adhesion ntawm tus neeg ua haujlwm cov cuab yeej siv thiab cov phab ntsa substrate, uas yog, shear resistance ntawm lub mortar. Qhov ntau dua qhov adhesion, qhov ntau dua shear resistance ntawm lub mortar, lub zog ntau dua los ntawm tus neeg ua haujlwm thaum siv, thiab kev ua haujlwm tsis zoo ntawm lub mortar. Lub adhesion ntawm MC yog nyob rau hauv nruab nrab theem ntawm cellulose ether khoom.
Hydroxypropyl methylcellulose (HPMC):
HPMC yooj yim soluble hauv dej, tab sis tej zaum yuav nyuaj rau yaj hauv dej kub. Txawm li cas los xij, nws qhov kub thiab txias hauv dej kub yog qhov siab dua li ntawm MC, thiab nws cov solubility hauv dej txias kuj zoo dua li ntawm MC.
Lub viscosity ntawm HPMC muaj feem xyuam rau qhov hnyav molecular, thiab cov viscosity siab thaum lub cev hnyav molecular loj. Kub kuj cuam tshuam rau nws cov viscosity, thiab cov viscosity txo qis thaum qhov kub thiab txias nce, tab sis qhov kub ntawm qhov nws viscosity txo qis dua li ntawm MC. Nws cov tshuaj yog ruaj khov ntawm chav tsev kub.
Cov dej tuav ntawm HPMC nyob ntawm qhov sib ntxiv thiab viscosity, thiab lwm yam. Cov dej tuav ntawm tib qhov sib ntxiv yog siab dua li ntawm MC.
HPMC ruaj khov rau cov kua qaub thiab alkalis, thiab nws cov tshuaj aqueous yog ruaj khov nyob rau hauv pH ntau ntawm 2 ~ 12. Caustic soda thiab txiv qaub dej tsis tshua muaj txiaj ntsig rau nws qhov kev ua tau zoo, tab sis alkali tuaj yeem ua kom nws cov kuab lom thiab nce viscosity. HPMC ruaj khov rau cov ntsev dav dav, tab sis thaum lub concentration ntawm ntsev tov yog siab, lub viscosity ntawm HPMC tshuaj nyhav nce.
HPMC tuaj yeem sib xyaw nrog cov dej-soluble polymer tebchaw los tsim ib qho kev sib xyaw ua ke, ntau dua viscosity tov, xws li polyvinyl cawv, starch ether, zaub pos hniav, thiab lwm yam.
HPMC muaj cov enzyme zoo dua li MC, thiab nws cov tshuaj tsis tshua muaj kev cuam tshuam rau cov enzymatic degradation dua MC. HPMC muaj adhesion zoo rau mortar tshaj MC.
Hydroxyethyl cellulose (HEC):
HEC yog soluble hauv dej txias thiab nyuaj rau yaj hauv dej kub. Cov tshuaj yog ruaj khov ntawm qhov kub thiab txias thiab tsis muaj cov khoom gel. Nws tuaj yeem siv rau hauv mortar rau lub sijhawm ntev ntawm qhov kub thiab txias, tab sis nws cov dej tuav tau qis dua MC.
HEC ruaj khov rau cov kua qaub thiab alkalis, alkali tuaj yeem ua kom nws cov kuab lom thiab ua kom cov viscosity me ntsis, thiab nws cov dispersibility hauv dej yog me ntsis qis dua MC thiab HPMC.
HEC muaj kev cuam tshuam zoo rau mortar, tab sis cov cement muaj lub sijhawm ntev dua.
HEC tsim los ntawm qee cov lag luam hauv tsev tau qis dua MC vim nws cov ntsiab lus dej siab thiab cov hmoov tshauv.
Carboxymethyl cellulose (CMC):
CMC yog ib qho ionic cellulose ether npaj los ntawm cov tshuaj tiv thaiv kab mob tom qab cov fibers ntuj (xws li paj rwb) tau kho nrog alkali thiab chloroacetic acid yog siv los ua tus neeg sawv cev etherifying. Qhov kev hloov pauv feem ntau yog nyob nruab nrab ntawm 0.4 thiab 1.4, thiab nws qhov kev ua tau zoo cuam tshuam los ntawm kev hloov pauv.
CMC muaj cov nyhuv thickening thiab emulsification stabilization, thiab tuaj yeem siv rau hauv cov dej haus uas muaj roj thiab cov protein los ua lub luag haujlwm emulsification stabilization.
CMC muaj cov nyhuv tuav dej. Hauv cov khoom noj nqaij, qhob cij, steamed buns 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 cov dej tsis muaj zog, ua kom cov khoom muaj txiaj ntsig, thiab ua kom saj.
CMC muaj cov nyhuv gelling thiab tuaj yeem siv los ua jelly thiab jam.
CMC tuaj yeem tsim ib zaj duab xis rau saum npoo ntawm cov zaub mov, uas muaj qee yam kev tiv thaiv ntawm cov txiv hmab txiv ntoo thiab zaub thiab ua rau lub neej ntev ntawm cov txiv hmab txiv ntoo thiab zaub.
Cov cellulose ethers txhua tus muaj lawv tus kheej cov khoom tshwj xeeb thiab cov chaw siv. Kev xaiv cov khoom tsim nyog yuav tsum tau txiav txim siab raws li kev thov tshwj xeeb thiab ib puag ncig.
Post lub sij hawm: Oct-29-2024