Methyl Cellulose (MC) Molecular formula \[C6H7O2(OH)3-h(OCH3)n1] x Refined paj rwb yog kho nrog alkali, thiab methyl chloride yog siv los ua etherification tus neeg sawv cev. Tom qab ib tug series ntawm cov tshuaj tiv thaiv, cellulose ether kev kho mob yog nqa tawm. Feem ntau, qhov degree ntawm kev hloov pauv yog 1.6 ~ 2.0, thiab qib kev hloov pauv txawv. Nws belongs rau non-ionic cellulose ether.
1. Methylcellulose yog soluble hauv dej txias, dej kub yuav ntsib teeb meem, thiab pH ntau ntawm cov kua dej aqueous yog qhov ruaj khov ntawm 3/12. Cov hmoov txhuv nplej siab, guar cov pos hniav thiab ntau lwm cov surfactants tau tshaj. Gelation tshwm sim thaum qhov kub nce mus txog qhov kub ntawm gelation.
Cov dej tuav ntawm methylcellulose nyob ntawm nws tus nqi ntxiv, viscosity, particle fineness thiab dissolution tus nqi. Feem ntau loj, me me, siab viscosity, siab tuav dej. Ntawm lawv, kev tuav dej muaj qhov cuam tshuam loj tshaj plaws, thiab qib viscosity tsis ncaj qha rau cov dej tuav. Tus nqi dissolution feem ntau yog nyob ntawm qhov kev hloov kho saum npoo ntawm cov cellulose hais thiab fineness ntawm cov khoom. Ntawm cov cellulose ethers saum toj no, methyl cellulose thiab hydroxypropyl methyl cellulose muaj cov dej khaws cia siab.
Kev hloov kub tuaj yeem cuam tshuam rau cov dej tuav ntawm methyl cellulose. - 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.
Methylcellulose muaj qhov cuam tshuam loj rau kev ua haujlwm thiab adhesion ntawm mortar. Qhov "stickiness" ntawm no yog hais txog qhov adhesion ntawm tus neeg ua haujlwm lub cuab yeej applicator thiab phab ntsa substrate, uas yog, shear resistance ntawm lub mortar. Viscosity, mortar shear lub zog, thiab lub zog xav tau los ntawm cov neeg ua haujlwm hauv kev siv kuj tseem loj heev, thiab kev siv tshuaj khib nyiab tsis zoo. Methylcellulose adhered ntawm theem nrab hauv cellulose ether cov khoom.
2. Hydroxypropyl methylcellulose (HPMC) [C 6 H 7 O 2 (OH) 3-mn (OCH 3 ) m, OCH 2 CH (OH) CH 3]] hydroxypropyl methyl cellulose Nyob rau xyoo tas los no, hom cellulose muaj nce sai heev. Nws yog non-ionic cellulose sib xyaw ether npaj los ntawm cov tshuaj tiv thaiv tom qab alkalization ntawm refined paj rwb alkali, uas propylene oxide thiab methyl chloride yog siv los ua etherification agents. Qhov kev hloov pauv feem ntau yog 1.2/2.0. Nws cov khoom sib txawv raws li qhov sib piv ntawm cov ntsiab lus methoxyl thiab hydroxypropyl cov ntsiab lus.
1. Hydroxypropyl methylcellulose muab faib ua hom kub-melt thiab hom instant. Nws qhov kub thiab txias hauv dej kub yog siab dua li ntawm methylcellulose. Nws kuj qhia tau hais tias muaj kev txhim kho zoo tshaj methylcellulose thaum yaj hauv dej txias.
Lub viscosity ntawm hydroxypropyl methylcellulose muaj feem xyuam rau qhov hnyav molecular, thiab qhov hnyav molecular siab. Kub kuj cuam tshuam rau nws cov viscosity, thaum kub nce, viscosity txo. Txawm li cas los xij, qhov cuam tshuam ntawm qhov kub ntawm viscosity yog qis dua li ntawm methyl cellulose. Cov tshuaj yog cia ruaj khov ntawm chav tsev kub.
3. Cov dej tuav ntawm hydroxypropyl methylcellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, thiab lwm yam, thiab cov dej tuav tus nqi tib yam yog siab dua li ntawm methyl cellulose.
4. Hydroxypropyl methylcellulose ruaj khov rau cov kua qaub thiab alkali, thiab nws cov kua aqueous yog ruaj khov nyob rau hauv pH ntau ntawm 2/12. Kev ua haujlwm ntawm caustic soda thiab txiv qaub dej tsis muaj kev cuam tshuam ntau, tab sis cov alkali tuaj yeem ua kom nws qhov kev sib cais, thiab cov viscosity nce ntxiv. Hydroxypropyl methylcellulose yog ruaj khov rau cov ntsev ntau, tab sis thaum lub concentration ntawm cov ntsev ntsev yog siab, lub viscosity ntawm hydroxypropyl methylcellulose tov yuav nce.
Hydroxypropyl methylcellulose tuaj yeem sib xyaw nrog cov dej-soluble polymers los ua ib qho kev sib xws, cov kua nplaum siab. Xws li polyvinyl cawv, starch ether, zaub pos hniav, thiab lwm yam.
Hydroxypropyl methylcellulose muaj enzyme zoo dua li methylcellulose, qhov ua tau ntawm enzymatic degradation ntawm nws cov tshuaj yog qis dua li ntawm methylcellulose, thiab adhesion ntawm hydroxypropylmethylcellulose rau mortar siv yog siab dua li ntawm methylcellulose. base cellulose.
Peb, hydroxyethyl cellulose (HEC) yog tsim los ntawm refined paj rwb kho nrog alkali, nyob rau hauv lub xub ntiag ntawm acetone, thiab ethylene oxide ua etherification tus neeg sawv cev. Nws qhov kev hloov pauv feem ntau yog 1.5/2.0. Nws muaj zog hydrophilicity thiab yooj yim rau nqus noo noo.
1. Hydroxyethyl cellulose yog soluble hauv dej txias, tab sis nws nyuaj rau yaj hauv dej kub. Cov tshuaj yog ruaj khov ntawm qhov kub thiab txias thiab tsis muaj cov khoom gel. Nws tuaj yeem siv tau ntev ntev hauv qhov kub thiab txias, tab sis nws cov dej tuav tau qis dua li ntawm methyl cellulose.
2. Hydroxyethyl cellulose ruaj khov rau cov kua qaub thiab alkali. Alkali accelerates nws dissolution, thiab nws viscosity nce me ntsis. Nws dispersion nyob rau hauv dej yog me ntsis phem dua li ntawm methyl cellulose thiab hydroxypropyl methyl cellulose.
3. Hydroxyethyl cellulose muaj kev ua tau zoo los tiv thaiv dai ntawm mortar, tab sis rau lub sijhawm ntev, qee qhov tsim tawm hauv tsev hydroxyethyl cellulose tau ua haujlwm qis dua li methyl cellulose vim nws cov dej loj thiab cov hmoov tshauv siab.
4. Carboxymethyl cellulose (CMC) \ [C6H7O2 (OH) 2och2COONa] (paj rwb, thiab lwm yam) ntawm ntuj fiber yog kho nrog alkali, thiab sodium chloroacetate yog siv los ua etherification tus neeg saib xyuas, tom qab ib tug series ntawm cov tshuaj tiv thaiv kev kho mob, nws yog ua rau ionic. cellulose ether. Qib ntawm kev hloov pauv feem ntau yog 0.4 / 1.4, thiab qhov kev hloov pauv tau muaj kev cuam tshuam ntau dua rau kev ua haujlwm.
Carboxymethyl cellulose muaj hygroscopicity siab, thiab cov chaw cia khoom dav dav muaj dej ntau.
2. Carboxymethyl cellulose aqueous kua tsis tsim gel, viscosity txo thaum kub nce, thiab viscosity yog irreversible thaum kub tshaj 50 ° C.
Nws stability yog heev cuam tshuam los ntawm pH. Feem ntau siv rau gypsum mortar, tsis yog rau cement mortar. Nyob rau hauv cov ntaub ntawv ntawm high alkalinity, nws yuav poob nws viscosity.
Nws cov dej tuav tau qis dua li ntawm methyl cellulose. Gypsum mortar muaj cov nyhuv retarding, txo lub zog. Tab sis tus nqi ntawm carboxymethyl cellulose yog qis dua li ntawm methyl cellulose.
Post lub sij hawm: Jan-13-2023