Cellulose ether nyob rau hauv npaj mix mortar

Lub luag haujlwm tseem ceeb ntawm cellulose ether nyob rau hauv npaj sib xyaw mortar:

Nyob rau hauv lub npaj sib tov mortar, cov cellulose ether ntxiv tus nqi yog tsawg heev, tab sis muaj peev xwm ho txhim kho cov kev ua tau zoo ntawm ntub mortar, mortar kev ua tau zoo yog ib tug loj additive. Tsim nyog xaiv ntau yam, sib txawv viscosity, txawv particle loj, txawv viscosity degree thiab ntxiv tus nqi ntawm cellulose ether

Nyob rau hauv lub npaj sib tov mortar, cov cellulose ether ntxiv tus nqi yog tsawg heev, tab sis muaj peev xwm ho txhim kho cov kev ua tau zoo ntawm ntub mortar, mortar kev ua tau zoo yog ib tug loj additive. Tsim nyog xaiv ntawm cellulose ether nrog ntau hom, sib txawv viscosity, txawv particle loj, txawv viscosity degree thiab ntxiv npaum li cas muaj txiaj ntsig zoo rau kev txhim kho cov khoom mortar qhuav. Tam sim no, ntau cov masonry thiab plastering mortars muaj kev tuav dej tsis zoo, thiab cov dej slurry sib cais yuav tshwm sim tom qab ob peb feeb ntawm kev sawv.

Kev tuav dej yog ib qho tseem ceeb ntawm kev ua haujlwm ntawm methyl cellulose ether, tab sis kuj tseem muaj ntau ntawm cov neeg tsim khoom hauv tsev qhuav, tshwj xeeb tshaj yog nyob rau sab qab teb ntawm cov tuam txhab kub siab dua kev txhawj xeeb txog kev ua haujlwm. Cov yam ntxwv cuam tshuam rau cov dej tuav cov nyhuv ntawm cov mortar qhuav suav nrog tus nqi ntawm MC, MC viscosity, particle fineness thiab ambient kub.

Cellulose ether yog ib qho hluavtaws polymer ua los ntawm ntuj cellulose ua raw khoom los ntawm kev hloov tshuaj. Cellulose ether yog derivative ntawm natural cellulose, cellulose ether ntau lawm thiab hluavtaws polymer yog txawv, nws cov khoom siv yooj yim tshaj plaws yog cellulose, natural polymer compounds. Vim qhov tshwj xeeb ntawm cov qauv cellulose, cellulose nws tus kheej tsis muaj peev xwm ua rau muaj kev cuam tshuam nrog etherifying tus neeg sawv cev. Txawm li cas los xij, tom qab kev kho mob ntawm tus neeg sawv cev o, lub zog hydrogen bonds ntawm cov saw hlau molecular thiab hauv cov saw hlau raug rhuav tshem, thiab kev ua haujlwm ntawm hydroxyl pawg tau tso tawm rau hauv alkali cellulose nrog lub peev xwm tshuaj tiv thaiv, thiab cellulose ether tau txais los ntawm cov tshuaj tiv thaiv ntawm ETHERifying agent - OH pab pawg rau hauv -OR pab pawg.

Cov khoom ntawm cellulose ethers nyob ntawm seb hom, tus lej thiab kev faib tawm ntawm cov khoom hloov pauv. Kev faib tawm ntawm cellulose ether kuj yog nyob ntawm hom kev hloov pauv, qib ntawm etherification, solubility thiab lwm yam kev thov tuaj yeem raug cais tawm. Raws li hom kev hloov pauv ntawm cov saw hlau molecular, nws tuaj yeem muab faib ua ib leeg ether thiab sib xyaw ether. MC feem ntau yog siv los ua ib qho ether, thaum HPMC yog ib qho ether sib xyaw. Methyl cellulose ether MC yog lub ntuj cellulose qabzib chav tsev ntawm hydroxyl methoxide hloov los ntawm cov khoom qauv mis yog [COH7O2 (OH) 3-H (OCH3) H] X, hydroxypropyl methyl cellulose ether HPMC yog ib chav nyob ntawm hydroxyl ib feem ntawm cov methoxide hloov los ntawm hydroxypropyl, lwm qhov ntawm cov khoom yog hloov los ntawm hydroxypropyl, Cov qauv qauv yog [C6H7O2 (OH) 3-MN (OCH3) M [OCH2CH (OH) CH3] N] X thiab hydroxyethyl methyl cellulose ether HEMC, uas yog dav siv thiab muag hauv khw.

Los ntawm solubility tuaj yeem muab faib ua hom ionic thiab hom tsis-ionic. Dej-soluble non-ionic cellulose ether yog tsim los ntawm alkyl ether thiab hydroxyl alkyl ether ob series ntawm ntau yam. Ionic CMC feem ntau yog siv rau hauv cov khoom siv hluavtaws, textile, luam ntawv, khoom noj khoom haus thiab kev siv roj av. Non-ionic MC, HPMC, HEMC thiab lwm yam yog siv hauv cov khoom siv hauv tsev, latex coatings, tshuaj, chemistry txhua hnub thiab lwm yam. Raws li thickening tus neeg saib xyuas, dej tuav tus neeg saib xyuas, stabilizer, dispersant, film forming agent.

Cellulose ether dej tuav: hauv kev tsim cov khoom siv hauv tsev, tshwj xeeb tshaj yog cov khib nyiab qhuav, cellulose ether plays lub luag haujlwm tsis tuaj yeem hloov tau, tshwj xeeb tshaj yog nyob rau hauv kev tsim cov mortar tshwj xeeb (hloov mortar), tab sis kuj yog ib feem tseem ceeb. Lub luag haujlwm tseem ceeb ntawm cov dej-soluble cellulose ether hauv mortar feem ntau muaj peb yam, ib qho yog cov dej tuav tau zoo, qhov thib ob yog kev cuam tshuam ntawm mortar sib xws thiab thixotropy, thiab qhov thib peb yog kev sib cuam tshuam nrog cov cement. Cellulose ether dej tuav, nyob ntawm lub hauv paus ntawm hydroscopicity, muaj pes tsawg leeg ntawm mortar, mortar txheej thickness, mortar dej xav tau, condensation khoom condensation lub sij hawm. Cov dej tuav ntawm cellulose ether los ntawm solubility thiab lub cev qhuav dej ntawm cellulose ether nws tus kheej. Nws yog qhov paub zoo tias cov saw cellulose molecular, txawm hais tias lawv muaj ntau cov hydrated OH pawg, yog insoluble hauv dej vim lawv cov qauv crystalline heev. Lub peev xwm hydration ntawm hydroxyl pab pawg ib leeg tsis txaus los them rau cov muaj zog intermolecular hydrogen bonds thiab van der Waals rog. Thaum cov khoom hloov pauv tau nkag mus rau hauv cov saw hlau molecular, tsis yog cov khoom hloov pauv tsuas yog rhuav tshem cov saw hlau hydrogen, tab sis kuj tseem muaj cov interchain hydrogen bonds tawg vim qhov sib txuas ntawm cov khoom sib txuas ntawm cov saw hlau uas nyob ib sab. Qhov loj dua qhov hloov pauv, qhov kev ncua deb ntawm molecules ntau dua. Qhov ntau dua qhov kev puas tsuaj ntawm hydrogen bond effect, cellulose lattice expansion, cov tshuaj rau hauv cellulose ether ua dej-soluble, tsim cov viscosity siab. Raws li qhov kub nce siab, cov dej ntawm cov polymer txo qis thiab cov dej ntawm cov saw hlau raug tsav tawm. Thaum lub cev qhuav dej txaus, cov molecules pib sib sau ua ke thiab cov gel folds tawm hauv peb-dimensional network.

Cov yam ntxwv cuam tshuam rau cov dej khaws cia ntawm mortar suav nrog cellulose ether viscosity, ntau npaum li cas, particle fineness thiab kev pabcuam kub.

Qhov ntau dua qhov viscosity ntawm cellulose ether, qhov dej tuav tau zoo dua. Viscosity yog qhov tseem ceeb ntawm kev ua haujlwm MC. Tam sim no, cov tuam txhab MC sib txawv siv cov kev sib txawv thiab cov cuab yeej los ntsuas qhov viscosity ntawm MC. Cov txheej txheem tseem ceeb suav nrog Haake Rotovisko, Hoppler, Ubbelohde thiab Brookfield. Rau tib yam khoom, cov txiaj ntsig ntawm viscosity ntsuas los ntawm ntau txoj kev sib txawv heev, qee qhov txawm tias ntau qhov sib txawv. Yog li ntawd, thaum sib piv viscosity, nws yuav tsum tau nqa tawm ntawm tib txoj kev sim, xws li kub, rotor, thiab lwm yam.

Feem ntau hais lus, qhov siab dua qhov viscosity, qhov zoo dua cov dej tuav. Txawm li cas los xij, qhov siab dua qhov viscosity yog, qhov siab dua qhov hnyav molecular ntawm MC yog, thiab qhov kev ua tiav ntawm kev sib cais yuav txo qis, uas muaj kev cuam tshuam tsis zoo rau lub zog thiab kev tsim kho ntawm mortar. Qhov siab dua qhov viscosity, qhov pom tseeb dua cov nyhuv ntawm mortar, tab sis nws tsis yog proportional rau kev sib raug zoo. Qhov siab dua qhov viscosity, cov khib nyiab ntub yuav ntau nplaum, ob qho tib si kev tsim kho, kev ua haujlwm ntawm cov nplaum nplaum nplaum thiab siab adhesion rau cov khoom siv hauv paus. Tab sis nws tsis muaj txiaj ntsig los ua kom lub zog muaj zog ntawm cov mortar ntub dej. Thaum lub sij hawm tsim kho, qhov kev ua tau zoo anti-sag tsis pom tseeb. Ntawm qhov tsis sib xws, qee qhov tsis muaj viscosity tab sis hloov kho methyl cellulose ethers muaj kev ua tau zoo hauv kev txhim kho lub zog ntawm cov khoom ntub dej.

Qhov ntau cellulose ether ntxiv rau hauv mortar, cov dej tuav tau zoo dua, qhov viscosity siab dua, cov dej tuav tau zoo dua.

Rau particle loj, qhov finer particle, qhov zoo dua cov dej tuav. Cov khoom loj ntawm cellulose ether tiv tauj nrog dej, qhov chaw tam sim ntawd yaj thiab tsim cov gel los qhwv cov khoom kom tiv thaiv cov dej molecules los ntawm kev txuas ntxiv mus, qee zaum ntev stirring tsis tuaj yeem sib npaug dispersed yaj, tsim cov av nkos flocculent tov los yog agglomerate. Lub solubility ntawm cellulose ether yog ib qho ntawm cov yam ntxwv los xaiv cellulose ether. Fineness kuj yog ib qho tseem ceeb Performance index ntawm methyl cellulose ether. MC rau cov mortar qhuav yuav tsum tau hmoov, dej tsis muaj dej, thiab fineness ntawm 20% ~ 60% particle loj tsawg dua 63um. Fineness cuam tshuam rau solubility ntawm methyl cellulose ether. Coarse MC feem ntau yog granular thiab tuaj yeem yaj tau yooj yim hauv dej yam tsis muaj agglomerating, tab sis qhov kev sib cais nrawm yog qeeb heev, yog li nws tsis haum rau siv hauv mortar qhuav. Hauv mortar qhuav, MC yog sib cais ntawm cov sib sau ua ke, cov khoom ua kom zoo thiab cov khoom siv cementing xws li cov cement, thiab tsuas yog cov hmoov uas zoo txaus tuaj yeem zam qhov clumping ntawm methyl cellulose ether thaum sib tov nrog dej. Thaum MC ntxiv dej kom yaj agglomerate, nws nyuaj heev rau disperse thiab yaj nws. MC nrog ntxhib fineness tsis tsuas yog khib nyiab, tab sis kuj txo lub zog hauv zos ntawm mortar. Thaum xws li mortar qhuav yog tsim nyob rau hauv ib tug loj cheeb tsam, lub curing ceev ntawm lub zos mortar qhuav yog ho txo, uas ua rau tawg los ntawm txawv sij hawm curing. Rau cov neeg kho tshuab txau mortar, vim lub sijhawm sib tov luv luv, qhov kev ua tau zoo dua.

Qhov zoo ntawm MC kuj muaj qee yam cuam tshuam rau nws cov dej tuav. Feem ntau hais lus, rau methyl cellulose ether nrog tib viscosity tab sis txawv fineness, lub finer cov dej tuav nyhuv yog zoo dua nyob rau hauv tib qhov sib ntxiv.

Cov dej tuav ntawm MC kuj muaj feem xyuam rau qhov kub thiab txias siv, thiab cov dej tuav ntawm methyl cellulose ether txo qis nrog qhov kub thiab txias. Tab sis nyob rau hauv cov ntaub ntawv siv tiag tiag, ntau qhov chaw ntawm cov mortar qhuav feem ntau yuav nyob rau hauv qhov kub thiab txias (siab tshaj 40 degrees) nyob rau hauv cov xwm txheej ntawm kev tsim kho nyob rau hauv kub substrate, xws li lub caij ntuj sov insolation ntawm sab nrauv phab ntsa putty plastering, uas feem ntau accelerates lub solidification ntawm. cement thiab qhuav mortar hardening. Qhov txo qis ntawm cov dej tuav tus nqi ua rau pom pom tseeb tias ob qho tib si constructability thiab cracking kuj raug cuam tshuam. Hauv qhov xwm txheej no, txo qhov cuam tshuam ntawm qhov kub thiab txias yog qhov tseem ceeb heev. Txawm hais tias cov additive ntawm methyl hydroxyethyl cellulose ether yog suav hais tias yog nyob rau hauv lub forefront ntawm kev tsim kho technology, nws dependence rau kub tseem yuav ua rau lub weakening ntawm cov khoom ntawm qhuav mortar. Txawm hais tias qhov nce ntawm methyl hydroxyethyl cellulose ntau npaum li cas (lub caij ntuj sov mis), kev tsim kho thiab kev tawg kuj tseem tsis tuaj yeem ua tau raws li qhov xav tau ntawm kev siv. Los ntawm qee qhov kev kho tshwj xeeb ntawm MC, xws li nce qib ntawm etherification, cov dej tuav cov nyhuv ntawm MC tuaj yeem tswj tau cov nyhuv zoo dua nyob rau hauv qhov kub thiab txias, kom nws tuaj yeem muab kev ua tau zoo dua hauv cov xwm txheej hnyav.

Tsis tas li ntawd, cellulose ether thickening thiab thixotropy: cellulose ether thib ob ua - thickening nyob ntawm: cellulose ether polymerization degree, tov concentration, shear rate, kub thiab lwm yam mob. Cov cuab yeej gelation ntawm kev daws yog tshwj xeeb rau alkyl cellulose thiab nws cov derivatives hloov. Cov yam ntxwv gelation muaj feem xyuam nrog kev hloov pauv, kev daws teeb meem thiab cov khoom ntxiv. Rau hydroxyl alkyl hloov derivatives, gel zog kuj muaj feem xyuam rau qib ntawm hydroxyl alkyl hloov kho. Rau qhov kev daws teeb meem ntawm cov viscosity tsawg MC thiab HPMC tuaj yeem npaj 10% -15% concentration tov, nruab nrab viscosity MC thiab HPMC tuaj yeem npaj 5% -10% tov, thiab siab viscosity MC thiab HPMC tsuas yog npaj tau 2% -3. % tov, thiab feem ntau cellulose ether viscosity grading kuj yog 1% -2% tov rau qib. Qhov hnyav molecular cellulose ether thickener efficiency, tib lub concentration ntawm kev daws, sib txawv molecular hnyav polymers muaj txawv viscosity, viscosity thiab molecular hnyav yuav qhia tau raws li nram no, [η] = 2.92 × 10-2 (DPn) 0.905, DPn yog qhov nruab nrab polymerization degree ntawm siab. Tsawg molecular hnyav cellulose ether ntxiv kom ua tiav lub hom phiaj viscosity. Nws cov viscosity tsawg dua nyob ntawm tus nqi shear, siab viscosity kom ua tiav lub hom phiaj viscosity, tus nqi yuav tsum tau ntxiv tsawg dua, viscosity nyob ntawm qhov thickening efficiency. Yog li ntawd, kom ua tiav ib qho kev sib xws, qee qhov ntawm cellulose ether (kev sib xyaw ntawm cov tshuaj) thiab cov tshuaj viscosity yuav tsum tau lav. Lub gelation kub ntawm cov tshuaj txo qis linearly nrog qhov nce ntawm cov concentration ntawm cov tshuaj, thiab gelation tshwm sim nyob rau hauv chav tsev kub tom qab ncav cuag ib tug tej yam concentration. HPMC muaj gelation concentration ntawm chav tsev kub.

Qhov sib xws kuj tuaj yeem hloov kho los ntawm kev xaiv qhov loj me thiab cellulose ethers nrog ntau qib kev hloov kho. Qhov kev hloov pauv yog kev qhia txog cov pab pawg hydroxyl alkyl hauv qee qhov kev hloov pauv ntawm cov pob txha pob txha ntawm MC. Los ntawm kev hloov pauv cov txiaj ntsig sib txawv ntawm ob tus neeg hloov pauv, uas yog, DS thiab MS txheeb ze hloov pauv qhov txiaj ntsig ntawm methoxy thiab hydroxyl pawg. Ntau yam khoom ntawm cellulose ether yuav tsum tau los ntawm kev hloov pauv cov txiaj ntsig sib txawv ntawm ob hom kev hloov pauv.

Kev sib raug zoo ntawm kev sib xws thiab kev hloov kho: qhov sib ntxiv ntawm cellulose ether cuam tshuam rau kev siv dej ntawm mortar, thiab hloov cov dej-binder piv ntawm cov dej thiab cov cement, uas yog cov nyhuv thickening. Qhov ntau npaum li cas, kev siv dej ntau dua.

Cellulose ethers siv hauv cov khoom siv hauv tsev yuav tsum yaj sai sai hauv dej txias thiab muab qhov zoo sib xws rau lub cev. Yog hais tias ib tug muab shear tus nqi tseem flocculent thiab colloidal nws yog ib tug substandard los yog tsis zoo cov khoom.

Kuj tseem muaj kev sib raug zoo ntawm cov cement slurry zoo ib yam thiab ntau npaum ntawm cellulose ether, cellulose ether tuaj yeem ua rau kom cov viscosity ntawm mortar ntau dua, qhov ntau npaum li cas, qhov pom tseeb ntawm cov nyhuv. Cellulose ether aqueous tov nrog siab viscosity muaj siab thixotropy, uas yog ib qho ntawm cov yam ntxwv ntawm cellulose ether. Aqueous kev daws teeb meem ntawm MC hom polymers feem ntau muaj pseudoplastic, uas tsis yog-thixotropic fluidity hauv qab lawv cov gel kub, tab sis Newtonian ndlwg zog ntawm qis shear tus nqi. Pseudoplasticity nce nrog qhov nce ntawm qhov hnyav ntawm molecular lossis concentration ntawm cellulose ether thiab tsis muaj kev hloov pauv ntawm hom thiab qib. Yog li, cellulose ethers ntawm tib qib viscosity, txawm tias MC, HPMC lossis HEMC, ib txwm qhia tib lub zog rheological ntev npaum li qhov concentration thiab kub nyob twj ywm. Thaum qhov kub nce, cov txheej txheem gel yog tsim thiab siab thixotropic ntws tshwm sim. Cellulose ethers nrog siab concentration thiab tsawg viscosity pom thixotropy txawm tias qis dua qhov kub ntawm gel. Cov cuab yeej no muaj txiaj ntsig zoo rau kev tsim vaj tsev mortar los kho nws cov dej ntws thiab ntws cov khoom dai. Nws yuav tsum tau piav qhia ntawm no tias qhov siab dua qhov viscosity ntawm cellulose ether, qhov dej tuav tau zoo dua, tab sis qhov siab dua qhov viscosity, qhov siab dua qhov txheeb ze molecular hnyav ntawm cellulose ether, qhov txo qis ntawm nws cov solubility, uas muaj kev cuam tshuam tsis zoo. lub mortar concentration thiab kev tsim kho. Qhov siab dua qhov viscosity, qhov pom tseeb dua cov nyhuv ntawm cov tshuaj khib nyiab, tab sis nws tsis yog kev sib raug zoo ntawm kev sib raug zoo. Qee qhov qis viscosity, tab sis hloov kho cellulose ether hauv kev txhim kho lub zog ntawm cov mortar ntub dej muaj kev ua tau zoo dua, nrog rau qhov nce ntawm viscosity, cellulose ether dej tuav tau zoo tuaj.

Cellulose ether retardation: cellulose ether lub luag haujlwm thib peb yog los ncua cov txheej txheem dej ntawm cov cement. Cellulose ether endows mortar nrog ntau yam khoom muaj txiaj ntsig, tab sis kuj txo cov dej thaum ntxov ntawm cov cement, ncua cov txheej txheem dej dynamic ntawm cov cement. Qhov no tsis zoo rau kev siv tshuaj khib nyiab hauv qhov chaw txias. Cov nyhuv retarding no yog cellulose ether molecule adsorption ntawm CSH thiab Ca (OH) 2 hydration khoom tshwm sim los ntawm, vim qhov nce ntawm pore kua viscosity, cellulose ether txo cov kev ua ntawm ions hauv cov tshuaj, yog li ncua cov txheej txheem hydration. Qhov siab dua qhov concentration ntawm cellulose ether nyob rau hauv cov khoom ntxhia gel, qhov pom tseeb dua cov nyhuv ntawm hydration ncua. Cellulose ether tsis tsuas yog ncua kev teeb tsa, tab sis kuj tseem muaj cov txheej txheem hardening ntawm cov cement mortar system. Cov nyhuv retarding ntawm cellulose ether nyob ntawm tsis tsuas yog nyob rau hauv nws cov concentration nyob rau hauv cov ntxhia gel system, tab sis kuj nyob rau hauv cov tshuaj. Qhov siab dua ntawm HEMC methylation, qhov zoo dua qhov cuam tshuam ntawm cellulose ether. Cov nyhuv retarding ntawm hydrophilic hloov yog muaj zog dua li ntawm cov dej-nce ntxiv. Tab sis cov viscosity ntawm cellulose ether tsis tshua muaj kev cuam tshuam rau hydration kinetics ntawm cement.

Nrog rau qhov nce ntawm cellulose ether cov ntsiab lus, lub sij hawm teem ntawm mortar nce ho. Lub sijhawm pib ntawm mortar muaj qhov sib raug zoo nrog cov ntsiab lus ntawm cellulose ether, thiab lub sijhawm teem sijhawm kawg muaj kev sib raug zoo nrog cov ntsiab lus ntawm cellulose ether. Peb tuaj yeem tswj lub sijhawm ua haujlwm ntawm mortar los ntawm kev hloov cov tshuaj cellulose ether.

Piv txwv li, nyob rau hauv npaj sib tov mortar, cellulose ether plays lub luag hauj lwm nyob rau hauv dej tuav, thickening, ncua sij hawm cement hydration zog, txhim kho kev tsim kho. Kev tuav dej zoo muaj peev xwm ua rau cov cement hydration ntau dua, tuaj yeem txhim kho cov dej viscosity ntawm cov khib nyiab ntub dej, txhim kho lub zog sib txuas ntawm mortar, kho lub sijhawm. Ntxiv cellulose ether rau cov neeg kho tshuab txau mortar tuaj yeem txhim kho cov tshuaj tsuag lossis cov twj tso kua mis thiab lub zog ntawm cov mortar. Yog li ntawd, cellulose ether yog dav siv los ua ib qho tseem ceeb additive nyob rau hauv npaj-mixed mortar.