MC yog methyl cellulose, uas yog ua los ntawm cellulose ether los ntawm kev kho cov paj rwb zoo nrog alkali, siv methane chloride ua tus neeg sawv cev etherification, thiab dhau los ntawm ntau yam kev tshuaj tiv thaiv. Feem ntau, qib ntawm kev hloov pauv yog 1.6 ~ 2.0, thiab solubility kuj txawv nrog ntau qib ntawm kev hloov pauv. Nws yog rau cov cellulose ether uas tsis yog ionic.
(1) Qhov khaws dej ntawm methyl cellulose nyob ntawm nws qhov ntxiv ntau npaum li cas, viscosity, qhov zoo ntawm cov khoom me me thiab qhov nrawm ntawm kev yaj. Feem ntau, yog tias qhov ntxiv ntau npaum li cas, qhov zoo me me, thiab qhov viscosity loj, qhov nrawm ntawm kev khaws dej siab. Ntawm lawv, qhov nrawm ntawm kev ntxiv muaj qhov cuam tshuam loj tshaj plaws rau qhov nrawm ntawm kev khaws dej, thiab qib ntawm viscosity tsis ncaj qha rau qib ntawm kev khaws dej. Qhov nrawm ntawm kev yaj feem ntau nyob ntawm qib ntawm kev hloov pauv ntawm qhov chaw ntawm cov khoom me me cellulose thiab qhov zoo ntawm cov khoom me me. Ntawm cov cellulose ethers saum toj no, methyl cellulose thiab hydroxypropyl methyl cellulose muaj qhov nrawm ntawm kev khaws dej siab dua.
(2) Methylcellulose yaj tau hauv dej txias, thiab nws yuav nyuaj rau yaj hauv dej kub. Nws cov kua dej ruaj khov heev hauv pH = 3 ~ 12. Nws muaj kev sib raug zoo nrog cov hmoov txhuv nplej siab, cov roj hmab guar, thiab lwm yam thiab ntau yam surfactants. Thaum qhov kub ncav cuag qhov kub gelation, gelation tshwm sim.
(3) Kev hloov pauv ntawm qhov kub thiab txias yuav cuam tshuam loj heev rau qhov ceev ntawm cov methyl cellulose uas khaws dej. Feem ntau, qhov kub siab dua, qhov kev khaws dej yuav phem dua. Yog tias qhov kub ntawm cov mortar tshaj 40 ° C, qhov kev khaws dej ntawm methyl cellulose yuav raug txo qis, cuam tshuam loj heev rau kev tsim cov mortar.
(4) Methyl cellulose muaj feem cuam tshuam loj rau kev tsim kho thiab kev nplaum ntawm cov mortar. Qhov "kev nplaum" ntawm no yog hais txog lub zog nplaum uas hnov ntawm tus neeg ua haujlwm lub cuab yeej thov thiab phab ntsa substrate, uas yog, qhov kev tiv thaiv shear ntawm cov mortar. Qhov kev nplaum yog siab, qhov kev tiv thaiv shear ntawm cov mortar yog loj, thiab lub zog uas cov neeg ua haujlwm xav tau hauv cov txheej txheem ntawm kev siv kuj loj, thiab kev ua haujlwm ntawm cov mortar tsis zoo. Methyl cellulose adhesion yog nyob rau theem nruab nrab hauv cov khoom cellulose ether.
HPMC yog hydroxypropyl methylcellulose, uas yog cov cellulose sib xyaw ether uas tsis yog ionic ua los ntawm paj rwb zoo tom qab alkalization, siv propylene oxide thiab methyl chloride ua cov neeg sawv cev etherification, thiab los ntawm ntau qhov kev tshuaj tiv thaiv. Qhov degree ntawm kev hloov pauv feem ntau yog 1.2 ~ 2.0. Nws cov khoom sib txawv vim yog qhov sib txawv ntawm cov ntsiab lus methoxyl thiab cov ntsiab lus hydroxypropyl.
(1) Hydroxypropyl methylcellulose yooj yim yaj hauv dej txias, thiab nws yuav ntsib teeb meem hauv kev yaj hauv dej kub. Tab sis nws qhov kub gelation hauv dej kub yog siab dua li ntawm methyl cellulose. Qhov solubility hauv dej txias kuj zoo dua piv rau methyl cellulose.
(2) Qhov viscosity ntawm hydroxypropyl methylcellulose muaj feem cuam tshuam nrog nws qhov hnyav molecular, thiab qhov loj dua qhov hnyav molecular, qhov siab dua qhov viscosity. Kub kuj cuam tshuam rau nws qhov viscosity, thaum kub nce, viscosity txo qis. Txawm li cas los xij, nws qhov viscosity siab muaj qhov kub qis dua li methyl cellulose. Nws cov kua ruaj khov thaum khaws cia rau hauv chav sov.
(3) Hydroxypropyl methylcellulose ruaj khov rau cov kua qaub thiab alkali, thiab nws cov kua dej ruaj khov heev hauv pH = 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 yaj sai dua thiab ua rau nws cov viscosity nce ntxiv. Hydroxypropyl methylcellulose ruaj khov rau cov ntsev feem ntau, tab sis thaum qhov concentration ntawm cov ntsev daws siab, qhov viscosity ntawm hydroxypropyl methylcellulose kua feem ntau nce ntxiv.
(4) Qhov khaws cia dej ntawm hydroxypropyl methylcellulose nyob ntawm nws qhov ntxiv, viscosity, thiab lwm yam, thiab nws qhov khaws cia dej nyob rau hauv tib qhov ntxiv yog siab dua li ntawm methyl cellulose.
(5) Hydroxypropyl methylcellulose tuaj yeem sib xyaw nrog cov polymer sib xyaw uas yaj tau hauv dej los ua cov kua nplaum uas sib xws thiab viscosity siab dua. Xws li polyvinyl cawv, hmoov txhuv nplej siab ether, cov roj zaub, thiab lwm yam.
(6) Qhov nplaum ntawm hydroxypropyl methylcellulose rau kev tsim kho mortar siab dua li ntawm methylcellulose.
(7) Hydroxypropyl methylcellulose muaj kev tiv thaiv enzyme zoo dua li methylcellulose, thiab nws cov kua tsis tshua muaj peev xwm raug rhuav tshem los ntawm cov enzymes dua li methylcellulose.
Lub sijhawm tshaj tawm: Plaub Hlis-17-2023