MC yog methyl cellulose, uas yog ua los ntawm cellulose ether los ntawm kev kho cov paj rwb refined nrog alkali, siv methane chloride ua etherification tus neeg sawv cev, thiab mus los ntawm ib tug series ntawm cov tshuaj tiv thaiv. 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.
(1) Cov dej tuav ntawm methyl cellulose 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.
(2) 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.
(3) Kev hloov ntawm qhov kub thiab txias yuav cuam tshuam rau cov dej tuav tus nqi ntawm methyl cellulose. Feem ntau, qhov kub thiab txias dua, qhov dej khaws cia tsis zoo. Yog hais tias lub mortar kub siab tshaj 40 ° C, cov dej tuav ntawm methyl cellulose yuav txo qis, cuam tshuam rau kev tsim kho ntawm mortar.
(4) Methyl cellulose muaj qhov cuam tshuam loj rau kev tsim kho thiab adhesion ntawm mortar. Qhov "adhesion" ntawm no yog hais txog cov nplaum nplaum ntawm tus neeg ua haujlwm cov cuab yeej siv thiab cov phab ntsa substrate, uas yog, shear resistance ntawm lub mortar. Lub adhesiveness yog siab, shear resistance ntawm lub mortar yog loj, thiab lub zog yuav tsum tau los ntawm cov neeg ua hauj lwm nyob rau hauv tus txheej txheem ntawm kev siv kuj loj, thiab kev tsim kho ntawm lub mortar yog tsis zoo. Methyl cellulose adhesion yog nyob rau theem nrab hauv cellulose ether cov khoom.
HPMC yog hydroxypropyl methylcellulose, uas yog non-ionic cellulose tov ether ua los ntawm cov paj rwb refined tom qab alkalization, siv propylene oxide thiab methyl chloride ua etherification agents, thiab 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.
(1) Hydroxypropyl methylcellulose yog yooj yim soluble nyob rau hauv dej txias, thiab 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.
(2) 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.
(3) Hydroxypropyl methylcellulose ruaj khov rau cov kua qaub thiab alkali, thiab nws cov tshuaj aqueous yog ruaj khov nyob rau hauv thaj tsam ntawm pH = 2 ~ 12. Caustic dej qab zib 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 cov 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.
(4) Cov dej tuav ntawm hydroxypropyl methylcellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, thiab lwm yam, thiab nws cov dej tuav tus nqi nyob rau hauv tib qhov sib ntxiv yog siab dua li ntawm methyl cellulose.
(5) Hydroxypropyl methylcellulose tuaj yeem sib xyaw nrog cov dej-soluble polymer compounds los ua ib qho kev daws teeb meem thiab siab dua viscosity. Xws li polyvinyl cawv, starch ether, zaub pos hniav, thiab lwm yam.
(6) Lub adhesion ntawm hydroxypropyl methylcellulose rau mortar siv yog siab dua li ntawm methylcellulose.
(7) Hydroxypropyl methylcellulose muaj enzyme zoo dua li methylcellulose, thiab nws cov tshuaj tsis tshua muaj peev xwm degraded los ntawm enzymes dua methylcellulose.
Post lub sij hawm: Apr-17-2023