Muaj pes tsawg hom cellulose muaj?

1. Cellulose ether

Kev tsim kho qib cellulose ether yog cov ntsiab lus dav dav rau cov khoom lag luam tsim los ntawm cov tshuaj tiv thaiv ntawm alkali cellulose thiab etherifying tus neeg sawv cev nyob rau hauv qee yam mob. Alkali cellulose yog hloov los ntawm cov neeg ua haujlwm sib txawv kom tau txais cov cellulose ethers sib txawv. Raws li cov khoom ionization ntawm cov khoom hloov, cellulose ethers tuaj yeem muab faib ua ob pawg: ionic (xws li carboxymethyl cellulose) thiab non-ionic (xws li methyl cellulose). Raws li hom kev hloov pauv, cellulose ether tuaj yeem muab faib ua mono-ether (xws li methyl cellulose) thiab sib xyaw ether (xws li hydroxypropyl methyl cellulose). Raws li kev sib txawv solubility, nws tuaj yeem muab faib ua dej-soluble (xws li hydroxyethyl cellulose) thiab organic solvent-soluble (xws li ethyl cellulose), thiab lwm yam. Cov tshuaj khib nyiab qhuav yog dej-soluble cellulose, thiab dej-soluble cellulose yog muab faib ua hom instant thiab nto kho ncua sij hawm dissolution hom.

Lub mechanism ntawm kev txiav txim ntawm cellulose ether nyob rau hauv mortar yog raws li nram no:

1. Tom qab cov cellulose ether nyob rau hauv lub mortar yog yaj nyob rau hauv dej, qhov zoo thiab niaj hnub faib ntawm cov cementitious cov ntaub ntawv nyob rau hauv lub system yog guaranteed vim lub nto kev ua si. Raws li kev tiv thaiv colloid, cov cellulose ether " qhwv" cov khoom siv thiab muab khi rau ntawm sab nrauv. Tsim ib zaj duab xis lubricating, ua kom lub mortar system ruaj khov, thiab tseem txhim kho cov kua dej ntawm cov mortar thaum lub sij hawm sib tov thiab smoothness ntawm kev tsim kho.
2. Vim nws cov qauv molecular, cov tshuaj cellulose ether ua rau cov dej hauv cov tshuaj khib nyiab tsis yooj yim ploj, thiab maj mam tso tawm rau lub sijhawm ntev, ua rau cov mortar nrog cov dej tuav tau zoo thiab ua haujlwm tau zoo.

2. Methyl cellulose

Methylcellulose (MC) molecular mis [C6H7O2(OH)3-h(OCH3) n]x.

Tom qab cov paj rwb refined yog kho nrog alkali, cellulose ether yog tsim los ntawm ib tug series ntawm cov tshuaj tiv thaiv nrog methane chloride ua etherification tus neeg sawv cev. 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. 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.
2. Cov dej tuav ntawm methylcellulose 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.
3. Kev hloov pauv hauv qhov kub thiab txias tuaj yeem cuam tshuam rau cov dej tuav 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. Methylcellulose muaj qhov cuam tshuam loj rau kev ua haujlwm 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.

3.Hydroxypropyl Methyl Cellulose

Cov mis mos molecular ntawm hydroxypropyl methylcellulose (HPMC) yog [C6H7O2(OH)3-mn(OCH3) m, OCH2CH(OH)CH3] n]x

Hydroxypropyl methylcellulose yog ib hom cellulose uas nws cov zis thiab noj tau nce sai. Nws yog non-ionic cellulose tov ether ua los ntawm refined paj rwb tom qab alkalization, siv propylene oxide thiab methyl chloride ua etherification tus neeg sawv cev, 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, tab sis 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. Cov dej tuav ntawm hydroxypropyl methylcellulose nyob ntawm nws cov nyiaj ntxiv, viscosity, thiab lwm yam, thiab nws cov dej tuav tus nqi ntawm tib qhov sib ntxiv yog siab dua li ntawm methyl cellulose.
4. Hydroxypropyl methylcellulose yog ruaj khov rau cov kua qaub thiab alkali, thiab nws cov kua 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.
5. Hydroxypropyl methylcellulose tuaj yeem tov nrog dej-soluble polymer compounds los tsim ib qho kev sib xyaw thiab ntau dua viscosity tov. Xws li polyvinyl cawv, starch ether, zaub pos hniav, thiab lwm yam.
6. Hydroxypropyl methylcellulose muaj enzyme zoo dua li methylcellulose, thiab nws cov tshuaj tsis tshua muaj peev xwm degraded los ntawm enzymes dua li methylcellulose.
7. Qhov adhesion ntawm hydroxypropyl methylcellulose rau mortar siv yog siab dua li ntawm methyl cellulose.

4.Hydroxyethyl cellulose

Hydroxyethyl cellulose (HEC)

Nws yog tsim los ntawm refined paj rwb kho nrog alkali, thiab reacted nrog ethylene oxide raws li etherification tus neeg sawv cev nyob rau hauv lub xub ntiag ntawm acetone. 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. Nws cov tshuaj yog ruaj khov ntawm qhov kub thiab txias yam tsis muaj gelling. Nws tuaj yeem siv tau ntev hauv qhov kub thiab txias hauv mortar, tab sis nws cov dej tuav qis dua li ntawm methyl cellulose.
2. Hydroxyethyl cellulose yog qhov ruaj khov rau cov kua qaub thiab alkali, thiab alkali tuaj yeem ua rau nws tawg thiab ua kom nws viscosity me ntsis. Nws dispersibility hauv dej yog me ntsis phem dua li ntawm methyl cellulose thiab hydroxypropyl methyl cellulose.
3. Hydroxyethyl cellulose muaj kev ua haujlwm zoo los tiv thaiv sag rau mortar, tab sis nws muaj sijhawm ntev dua rau cov cement.
4. Kev ua tau zoo ntawm hydroxyethyl cellulose ua los ntawm qee lub tuam txhab hauv tsev yog pom tseeb qis dua li ntawm methyl cellulose vim nws cov ntsiab lus dej siab thiab cov hmoov tshauv siab.

5.Carboxymethyl cellulose

Carboxymethylcellulose (CMC) [C6H7O2(OH)2OCH2COONa] n

Ionic cellulose ether yog tsim los ntawm ntuj fibers (paj rwb, thiab lwm yam) tom qab kev kho alkali, siv sodium mono-chloroacetate ua tus neeg sawv cev etherification, thiab tau txais kev kho cov tshuaj tiv thaiv. Qib ntawm kev hloov pauv feem ntau yog 0.4 ~ 1.4, thiab nws qhov kev ua tau zoo cuam tshuam los ntawm qib hloov pauv.

1. Carboxymethyl cellulose yog hygroscopic ntau dua, thiab nws yuav muaj dej ntau dua thaum khaws cia rau hauv cov xwm txheej.
2. Carboxymethyl cellulose aqueous kua tsis tsim gel, thiab viscosity txo nrog qhov kub thiab txias. Thaum qhov kub siab tshaj 50 ° C, viscosity yog irreversible.
3. Nws stability yog heev cuam tshuam los ntawm pH. Feem ntau, nws tuaj yeem siv rau hauv gypsum-raws li mortar, tab sis tsis yog hauv cov cement-based mortar. Thaum alkaline heev, nws poob viscosity.
4. Nws cov dej tuav tau qis dua li ntawm methyl cellulose. Nws muaj cov nyhuv retarding ntawm gypsum-raws li mortar thiab txo nws lub zog. Txawm li cas los xij, tus nqi ntawm carboxymethyl cellulose yog qis dua li ntawm methyl cellulose.