A:
MC yog methyl cellulose: yog refined paj rwb tom qab kho alkali, methane chloride ua etherifying tus neeg sawv cev, los ntawm ib tug series ntawm cov tshuaj tiv thaiv ua cellulose ether. Feem ntau, qhov degree ntawm kev hloov pauv yog 1.6 ~ 2.0, thiab cov solubility sib txawv nrog rau qib ntawm kev hloov pauv. belongs rau nonionic cellulose ether.
(1) Cov dej tuav ntawm methyl cellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, particle fineness thiab dissolution tus nqi. Feem ntau ntxiv cov nyiaj loj, me me fineness, viscosity, dej tuav tus nqi siab. Tus nqi ntawm cov additives muaj kev cuam tshuam zoo rau cov dej tuav tus nqi, thiab cov viscosity tsis proportional rau cov dej tuav tus nqi. Tus nqi dissolution feem ntau yog nyob ntawm qhov kev hloov kho ntawm qhov chaw thiab qhov zoo ntawm cov khoom ntawm cellulose. Hauv cov saum toj no ob peb cellulose ethers, methyl cellulose thiab HPMC hydroxypropyl methyl cellulose dej tuav tus nqi siab dua.
(2) Methyl cellulose yog soluble hauv dej txias, uas nyuaj rau yaj hauv dej kub. Nws cov tshuaj aqueous yog ruaj khov nyob rau hauv pH = 3 ~ 12. Nws muaj kev sib raug zoo nrog cov hmoov txhuv nplej siab, guanidine cov pos hniav thiab ntau surfactants. Gelation tshwm sim thaum qhov kub nce mus txog qhov kub thiab txias.
(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 qhov kub ntawm mortar ntau tshaj 40 ℃, cov dej tuav ntawm methyl cellulose yuav loj zuj zus, uas cuam tshuam rau lub constructability ntawm mortar.
(4) Methyl cellulose muaj kev cuam tshuam rau kev tsim kho thiab adhesion ntawm mortar. "Adhesion" ntawm no yog hais txog qhov adhesion xav tau los ntawm tus neeg ua haujlwm ntawm lub cuab yeej thiab cov phab ntsa substrate, uas yog lub shear tsis kam ntawm lub mortar. Adhesion yog loj, shear resistance ntawm mortar yog loj, 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 mortar yog tsis zoo. Hauv cov khoom lag luam cellulose ether, qhov adhesion ntawm methyl cellulose yog nyob rau theem nrab.
HPMC yog hydroxypropyl methyl cellulose: nws yog ua los ntawm refined paj rwb tom qab alkali kev kho mob, nrog propylene oxide thiab chloromethane ua etherifying tus neeg saib xyuas, los ntawm ib tug series ntawm cov tshuaj tiv thaiv thiab ua los ntawm non-ionic cellulose tov ether. Qhov kev hloov pauv feem ntau yog 1.2 ~ 2.0. Nws cov khoom sib txawv nrog qhov feem ntawm methoxy thiab hydroxypropyl cov ntsiab lus.
(1) HPMC hydroxypropyl methyl cellulose yog yooj yim soluble nyob rau hauv dej txias, uas yog nyuaj rau yaj nyob rau hauv dej kub. Txawm li cas los xij, nws qhov kub thiab txias hauv dej kub yog pom tseeb siab dua li ntawm methyl cellulose. Solubility ntawm methyl cellulose hauv dej txias kuj tau txhim kho zoo heev.
(2) Lub viscosity ntawm HPMC hydroxypropyl methyl cellulose muaj feem xyuam rau nws qhov hnyav molecular, thiab siab dua qhov hnyav molecular, qhov viscosity siab dua. Kub kuj cuam tshuam viscosity. viscosity txo qis thaum kub nce. Tab sis nws cov viscosity siab kub nyhuv yog qis dua li ntawm methyl cellulose. Cov tshuaj yog ruaj khov thaum khaws cia ntawm chav tsev kub.
(3) HPMC hydroxypropyl methyl cellulose yog ruaj khov rau cov kua qaub thiab lub hauv paus, thiab nws cov kua aqueous 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 cov khoom, tab sis alkali tuaj yeem ua kom nws qhov kev sib cais thiab txhim kho cov viscosity. HPMC hydroxypropyl methyl cellulose ruaj khov rau cov ntsev dav dav, tab sis thaum cov ntsev ntsev ntau ntau, cov viscosity ntawm HPMC hydroxypropyl methyl cellulose tov yuav nce.
(4) Cov dej tuav ntawm HPMC hydroxypropyl methyl cellulose nyob ntawm nws qhov ntau npaum thiab viscosity, thiab cov dej tuav tus nqi ntawm HPMC hydroxypropyl methyl cellulose yog siab dua li ntawm methyl cellulose ntawm tib qhov ntau npaum.
(5) HPMC hydroxypropyl methyl cellulose tuaj yeem tov nrog cov dej-soluble polymer compounds los ua ib yam, ntau dua viscosity tov. Xws li polyvinyl cawv, starch ether, zaub kua nplaum thiab lwm yam.
(6) Lub adhesion ntawm HPMC hydroxypropyl methyl cellulose rau mortar siv yog siab dua li ntawm methyl cellulose.
(7) HPMC hydroxypropyl methyl cellulose muaj enzyme zoo dua li methyl cellulose, thiab nws cov tshuaj enzyme degradation muaj peev xwm qis dua li ntawm methyl cellulose.
Post lub sij hawm: May-26-2022