MC yog methyl cellulose, uas tau los ntawm kev kho cov paj rwb zoo nrog alkali, siv methyl chloride ua tus neeg sawv cev etherifying, thiab ua cellulose ether los ntawm ntau yam kev tshuaj tiv thaiv. Feem ntau, qib kev hloov pauv yog 1.6 ~ 2.0, thiab solubility kuj txawv nrog ntau qib kev hloov pauv. Nws yog rau cov cellulose ether uas tsis yog ionic.
(1) Kev khaws cia dej ntawmmethyl celluloseNyob 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 ntau ntxiv ntau, qhov zoo me me, thiab qhov viscosity loj, qhov nrawm ntawm kev khaws dej siab. Ntawm lawv, qhov ntau ntxiv muaj qhov cuam tshuam loj tshaj plaws rau qhov nrawm ntawm kev khaws dej, thiab qib ntawm viscosity tsis sib npaug rau qib ntawm kev khaws dej. Qhov nrawm ntawm kev yaj feem ntau nyob ntawm qib kev hloov pauv ntawm qhov chaw ntawm cov khoom 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, tab sis nyuaj rau yaj hauv dej kub, thiab 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, qhov tshwm sim ntawm gelation tshwm sim.
(3) Qhov kev hloov pauv ntawm qhov kub thiab txias yuav cuam tshuam loj heev rau qhov ceev ntawm cov dej ntawm methyl cellulose. Feem ntau, qhov kub siab dua, qhov kev khaws dej phem dua. Yog tias qhov kub ntawm cov mortar tshaj 40 ° C, qhov kev khaws dej ntawm methyl cellulose yuav phem dua, uas yuav cuam tshuam loj heev rau kev ua haujlwm ntawm cov mortar.
(4) Methyl cellulose muaj feem cuam tshuam loj rau kev ua haujlwm thiab kev nplaum ntawm cov mortar. "Kev nplaum" ntawm no yog hais txog qhov kev 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 loj, qhov kev tiv thaiv shear ntawm cov mortar yog loj, thiab lub zog uas cov neeg ua haujlwm xav tau hauv cov txheej txheem siv kuj loj, thiab kev tsim kho ntawm cov mortar tsis zoo. Methylcellulose adhesion yog nyob rau theem nruab nrab hauv cov khoom cellulose ether.
HPMC yog hydroxypropyl methyl cellulose, uas yog cov cellulose sib xyaw ether uas tsis yog ionic ua los ntawm paj rwb zoo tom qab kho alkali, siv propylene oxide thiab methyl chloride ua cov neeg sawv cev etherifying, thiab los ntawm ntau yam kev tshuaj tiv thaiv. Qhov degree ntawm kev hloov pauv feem ntau yog 1.2 txog 2.0. Nws cov khoom sib txawv nyob ntawm qhov sib piv ntawm methoxyl cov ntsiab lus thiab hydroxypropyl cov ntsiab lus.
(1) Hydroxypropyl methylcellulose yooj yim yaj hauv dej txias, tab sis 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. Kev yaj hauv dej txias kuj zoo dua piv rau methyl cellulose.
(2) Qhov viscosity ntawm hydroxypropyl methylcellulose muaj feem cuam tshuam rau qhov loj ntawm 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. Tab sis nws qhov viscosity tsis cuam tshuam los ntawm qhov kub siab dua li methyl cellulose. Nws cov kua ruaj khov ntawm kev khaws cia ntawm chav tsev kub.
(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 cov viscosity nce ntxiv. Hydroxypropyl methylcellulose ruaj khov rau cov ntsev feem ntau, tab sis thaum qhov concentration ntawm cov kua ntsev siab, qhov viscosity ntawm cov kua hydroxypropyl methylcellulose feem ntau nce ntxiv.
(4) Kev khaws cia dej ntawmhydroxypropyl methylcellulosenyob ntawm nws qhov ntxiv ntau npaum li cas, viscosity, thiab lwm yam. Qhov ceev ntawm kev khaws dej nyob rau hauv tib qho ntxiv ntau dua li ntawm methyl cellulose.
(5) Hydroxypropyl methylcellulose tuaj yeem sib xyaw nrog cov polymer sib xyaw uas yaj tau hauv dej los tsim cov tshuaj uas muaj viscosity sib xws thiab 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 zoo dua rau cov enzymes dua li methylcellulose, thiab nws cov kua enzymatic degradation possibilities qis dua li ntawm methylcellulose.
Lub sijhawm tshaj tawm: Plaub Hlis-28-2024