Methylcellulose (MC)
Cov mis mos molecular ntawm methylcellulose (MC) yog:
[C6H7O2(OH)3-h(OCH3)n\]x
Cov txheej txheem tsim khoom yog ua kom cellulose ether los ntawm cov tshuaj tiv thaiv tom qab cov paj rwb refined yog kho nrog alkali, thiab methyl chloride yog siv los ua tus neeg sawv cev etherification. Feem ntau, qhov degree ntawm kev hloov pauv yog 1.6 ~ 2.0, thiab cov solubility kuj txawv nrog ntau qib kev hloov pauv. Nws belongs rau non-ionic cellulose ether.
Methylcellulose yog soluble hauv dej txias, thiab nws yuav nyuaj rau yaj hauv dej kub. Nws cov tshuaj aqueous yog ruaj khov nyob rau hauv thaj tsam ntawm pH = 3 ~ 12.
Nws muaj kev sib raug zoo nrog cov hmoov txhuv nplej siab, cov pos hniav, thiab lwm yam thiab ntau surfactants. Thaum qhov kub nce mus txog qhov kub thiab txias, gelation tshwm sim.
Cov dej tuav ntawm methylcellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, particle fineness thiab dissolution tus nqi.
Feem ntau, yog tias qhov sib ntxiv yog qhov loj, qhov zoo me me, thiab cov viscosity loj, cov dej tuav tau siab. Ntawm lawv, qhov sib ntxiv muaj qhov cuam tshuam loj tshaj plaws ntawm cov dej tuav tus nqi, thiab qib ntawm viscosity tsis ncaj qha mus rau theem ntawm cov dej tuav tus nqi. Tus nqi dissolution feem ntau yog nyob ntawm qhov kev hloov kho saum npoo ntawm cellulose hais thiab particle fineness.
Ntawm cov cellulose ethers saum toj no, methyl cellulose thiab hydroxypropyl methyl cellulose muaj cov dej tuav ntau dua.
Carboxymethylcellulose (CMC)
Carboxymethyl cellulose, tseem hu ua sodium carboxymethyl cellulose, feem ntau hu ua cellulose, cmc, thiab lwm yam, yog ib qho anionic linear polymer, sodium ntsev ntawm cellulose carboxylate, thiab yog txuas ntxiv thiab inexhaustible. Cov khoom siv tshuaj lom neeg.
Nws yog tsuas yog siv rau hauv kev lag luam tshuaj ntxuav tes, kev lag luam khoom noj thiab roj av drilling kua, thiab cov nyiaj siv hauv cov tshuaj pleev ib ce tsuas yog kwv yees li 1%.
Ionic cellulose ether yog tsim los ntawm ntuj fibers (paj rwb, thiab lwm yam) tom qab kev kho alkali, siv sodium monochloroacetate ua tus neeg sawv cev etherification, thiab tau txais kev kho cov tshuaj tiv thaiv.
Qib ntawm kev hloov pauv feem ntau yog 0.4 ~ 1.4, thiab nws qhov kev ua tau zoo cuam tshuam los ntawm qib hloov pauv.
CMC muaj peev xwm ua tau zoo heev, thiab nws cov tshuaj aqueous muaj peev xwm tshem tawm tau zoo, tab sis tsis muaj qhov tseeb ntawm cov yas deformation.
Thaum CMC dissolves, depolymerization tiag tiag tshwm sim. Lub viscosity pib nce thaum lub sij hawm dissolution, dhau los ntawm qhov siab tshaj plaws, thiab tom qab ntawd poob mus rau toj siab. Qhov tshwm sim viscosity yog cuam tshuam nrog depolymerization.
Lub degree ntawm depolymerization yog ze ze rau tus nqi ntawm cov kuab tshuaj tsis zoo (dej) hauv formulation. Hauv cov kuab tshuaj tsis zoo, xws li cov tshuaj txhuam hniav uas muaj glycerin thiab dej, CMC yuav tsis ua tiav depolymerize thiab yuav ncav cuag qhov sib npaug.
Nyob rau hauv cov ntaub ntawv ntawm ib tug muab dej concentration, qhov ntau hydrophilic hloov CMC yog yooj yim dua rau depolymerize tshaj qhov tsawg hloov CMC.
Hydroxyethylcellulose (HEC)
HEC yog tsim los ntawm kev kho cov paj rwb refined nrog alkali, thiab tom qab ntawd reacting nrog ethylene oxide ua etherification tus neeg sawv cev nyob rau hauv lub xub ntiag ntawm acetone. Qhov kev hloov pauv feem ntau yog 1.5 ~ 2.0. Nws muaj zog hydrophilicity thiab yooj yim rau nqus noo noo.
Hydroxyethyl cellulose yog soluble hauv dej txias, tab sis nws nyuaj rau yaj hauv dej kub. Nws cov tshuaj yog ruaj khov ntawm qhov kub thiab txias yam tsis muaj gelling.
Nws ruaj khov rau cov kua qaub thiab cov hauv paus. Alkalis tuaj yeem ua kom nrawm nrawm rau nws qhov kev sib cais thiab ua kom nws cov viscosity me ntsis. Nws dispersibility hauv dej yog me ntsis phem dua li ntawm methyl cellulose thiab hydroxypropyl methyl cellulose.
Hydroxypropyl Methyl Cellulose (HPMC)
Cov mis mos molecular ntawm HPMC yog:
\[C6H7O2(OH)3-mn(OCH3)m,OCH2CH(OH)CH3\]n\]x
Hydroxypropyl methylcellulose yog ib hom cellulose uas nws cov zis thiab noj tau nce sai.
Nws yog non-ionic cellulose tov ether ua los ntawm refined paj rwb tom qab alkalization, siv propylene oxide thiab methyl chloride ua etherification tus neeg sawv cev, los ntawm ib tug series ntawm cov tshuaj tiv thaiv. Qhov kev hloov pauv feem ntau yog 1.2 ~ 2.0.
Nws cov khoom sib txawv vim qhov sib txawv ntawm cov ntsiab lus methoxyl thiab hydroxypropyl cov ntsiab lus.
Hydroxypropyl methylcellulose yog yooj yim soluble nyob rau hauv dej txias, tab sis nws yuav ntsib teeb meem nyob rau hauv dissolving nyob rau hauv dej kub. Tab sis nws qhov kub thiab txias hauv dej kub yog siab dua li ntawm methyl cellulose. Lub solubility hauv dej txias kuj zoo heev piv nrog methyl cellulose.
Lub viscosity ntawm hydroxypropyl methylcellulose muaj feem xyuam rau nws qhov hnyav molecular, thiab qhov loj dua qhov hnyav molecular, qhov viscosity siab dua. Kub kuj cuam tshuam rau nws cov viscosity, thaum kub nce, viscosity txo. Txawm li cas los xij, nws cov viscosity siab muaj qhov kub qis dua li methyl cellulose. Nws cov tshuaj yog ruaj khov thaum khaws cia ntawm chav tsev kub.
Cov dej tuav ntawm hydroxypropyl methylcellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, thiab lwm yam, thiab nws cov dej tuav tus nqi ntawm tib qhov sib ntxiv yog siab dua li ntawm methyl cellulose.
Hydroxypropyl methylcellulose yog ruaj khov rau cov kua qaub thiab alkali, thiab nws cov kua aqueous yog ruaj khov nyob rau hauv thaj tsam ntawm pH = 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 tawg thiab ua kom nws viscosity.
Hydroxypropyl methylcellulose yog ruaj khov rau cov ntsev ntau, tab sis thaum lub concentration ntawm ntsev tov yog siab, lub viscosity ntawm hydroxypropyl methylcellulose tov nyhav nce.
Hydroxypropyl methylcellulose tuaj yeem tov nrog dej-soluble polymer compounds los ua ib qho kev sib xyaw thiab ntau dua viscosity tov. Xws li polyvinyl cawv, starch ether, zaub pos hniav, thiab lwm yam.
Hydroxypropyl methylcellulose muaj enzyme zoo dua li methylcellulose, thiab nws cov tshuaj tsis tshua muaj enzyme degraded dua li methylcellulose.
Post lub sij hawm: Feb-14-2023