Hauv cov khoom sib xyaw ua ke, qhov sib ntxiv ntawm cellulose ether yog tsawg heev, tab sis nws tuaj yeem txhim kho kev ua haujlwm ntawm cov khib nyiab ntub, thiab nws yog ib qho tseem ceeb ntxiv uas cuam tshuam rau kev tsim kho ntawm mortar. Tsim nyog xaiv ntawm cellulose ethers ntawm ntau yam, txawv viscosities, txawv particle loj, txawv degrees ntawm viscosity thiab ntxiv cov nyiaj yuav muaj txiaj ntsig zoo rau kev txhim kho kev ua haujlwm ntawm cov hmoov qhuav mortar. Tam sim no, ntau cov masonry thiab plastering mortars muaj kev tuav dej tsis zoo, thiab cov dej slurry yuav sib cais tom qab ob peb feeb ntawm kev sawv. Kev tuav dej yog ib qho tseem ceeb ntawm methyl cellulose ether, thiab nws kuj yog ib qho kev ua tau zoo uas ntau lub tsev tsim khoom qhuav-sib xyaw, tshwj xeeb tshaj yog cov nyob rau yav qab teb cov cheeb tsam uas muaj qhov kub thiab txias, ua tib zoo saib xyuas. Cov yam ntxwv cuam tshuam rau cov dej tuav cov nyhuv ntawm cov tshuaj khib nyiab qhuav suav nrog cov nyiaj MC ntxiv, qhov viscosity ntawm MC, qhov zoo ntawm cov khoom thiab qhov kub ntawm qhov chaw siv.
1. Lub tswv yim
Cellulose ether yog ib qho hluavtaws polymer ua los ntawm ntuj cellulose los ntawm kev hloov tshuaj lom neeg. Cellulose ether yog derivative ntawm natural cellulose. Kev tsim cov cellulose ether yog txawv los ntawm hluavtaws polymers. Nws cov khoom siv yooj yim tshaj plaws yog cellulose, lub ntuj polymer compound. Vim qhov tshwj xeeb ntawm cov qauv cellulose, cellulose nws tus kheej tsis muaj peev xwm ua rau cov tshuaj etherification. Txawm li cas los xij, tom qab kev kho mob ntawm tus neeg mob o, lub zog hydrogen bonds ntawm cov saw hlau molecular thiab cov chains raug rhuav tshem, thiab cov active tso tawm ntawm pawg hydroxyl los ua reactive alkali cellulose. Tau txais cellulose ether.
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 ethers kuj yog nyob ntawm hom kev hloov pauv, qib ntawm etherification, solubility thiab lwm yam khoom siv. Raws li hom kev hloov pauv ntawm cov saw hlau molecular, nws tuaj yeem muab faib ua monoether thiab sib xyaw ether. MC peb feem ntau siv yog monoether, thiab HPMC yog sib xyaw ether. Methyl cellulose ether MC yog cov khoom lag luam tom qab cov pab pawg hydroxyl ntawm cov piam thaj hauv cov cellulose yog hloov los ntawm methoxy. Nws yog ib qho khoom tau los ntawm kev hloov ib feem ntawm pawg hydroxyl ntawm chav tsev nrog methoxy pawg thiab lwm qhov nrog ib pawg hydroxypropyl. Cov qauv qauv yog [C6H7O2(OH) 3-mn(OCH3)m[OCH2CH(OH)CH3]n] x Hydroxyethyl methyl cellulose ether HEMC, cov no yog cov hom tseem ceeb uas tau siv thiab muag hauv khw.
Nyob rau hauv cov nqe lus ntawm solubility, nws yuav muab faib ua ionic thiab non-ionic. Dej-soluble non-ionic cellulose ethers yog tsim los ntawm ob series ntawm alkyl ethers thiab hydroxyalkyl ethers. Ionic CMC feem ntau yog siv rau hauv cov khoom siv hluavtaws, textile printing thiab dyeing, zaub mov thiab roj tshawb nrhiav. Non-ionic MC, HPMC, HEMC, thiab lwm yam yog siv rau hauv cov ntaub ntawv tsim kho, latex coatings, tshuaj, tshuaj txhua hnub, thiab lwm yam. Siv ua thickener, dej tuav tus neeg saib xyuas, stabilizer, dispersant thiab zaj duab xis tsim tus neeg sawv cev.
Qhov thib ob, cov dej tuav ntawm cellulose ether
Kev tuav dej ntawm cellulose ether: Hauv kev tsim cov khoom siv hauv tsev, tshwj xeeb tshaj yog cov hmoov qhuav mortar, cellulose ether plays lub luag haujlwm tsis tuaj yeem hloov tau, tshwj xeeb tshaj yog nyob rau hauv cov khoom tshwj xeeb mortar (hloov mortar), nws yog ib qho tseem ceeb thiab tseem ceeb tivthaiv.
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, lwm qhov yog kev cuam tshuam ntawm kev sib xws thiab thixotropy ntawm mortar, thiab qhov thib peb yog kev sib cuam tshuam nrog cov cement. Cov dej tuav cov nyhuv ntawm cellulose ether nyob ntawm qhov nqus dej ntawm lub hauv paus txheej, muaj pes tsawg leeg ntawm mortar, lub thickness ntawm lub mortar txheej, cov dej xav tau ntawm cov mortar, thiab lub sij hawm teem ntawm cov khoom siv. Cov dej tuav ntawm cellulose ether nws tus kheej los ntawm solubility thiab lub cev qhuav dej ntawm cellulose ether nws tus kheej. Raws li peb txhua tus paub, txawm hais tias cov cellulose molecular saw muaj ntau ntawm cov hydratable OH pawg, nws tsis yog soluble hauv dej, vim hais tias cov qauv cellulose muaj ib tug high degree ntawm crystallinity.
Lub peev xwm hydration ntawm hydroxyl pawg ib leeg tsis txaus los npog cov hydrogen bonds thiab van der Waals rog ntawm cov molecules. Yog li ntawd, nws tsuas swells tab sis tsis yaj nyob rau hauv dej. Thaum ib qho kev hloov pauv tau nkag mus rau hauv cov saw hlau molecular, tsis yog tsuas yog cov khoom hloov pauv puas tsuaj rau cov saw hlau hydrogen, tab sis kuj tseem cuam tshuam cov interchain hydrogen daim ntawv cog lus raug rhuav tshem vim qhov sib txuas ntawm cov khoom sib hloov ntawm cov saw hlau uas nyob ib sab. Qhov loj dua qhov hloov pauv, qhov kev ncua deb ntawm cov molecules ntau dua. Qhov deb dua. Qhov ntau dua qhov cuam tshuam ntawm kev rhuav tshem hydrogen bonds, cellulose ether ua dej-soluble tom qab cellulose lattice nthuav dav thiab cov tshuaj nkag mus, tsim cov tshuaj viscosity siab. Thaum qhov kub nce siab, cov dej ntawm cov polymer tsis muaj zog, thiab cov dej ntawm cov saw hlau raug tsav tawm. Thaum lub cev qhuav dej txaus, cov molecules pib sib sau ua ke, ua ib qho kev sib txuas ntawm peb sab gel thiab muab tais tawm.
Cov yam ntxwv cuam tshuam rau cov dej tuav ntawm mortar suav nrog cellulose ether viscosity, ntxiv tus nqi, particle fineness thiab siv 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 yog Haake Rotovisko, Hoppler, Ubbelohde thiab Brookfield. Rau tib yam khoom, cov txiaj ntsig viscosity ntsuas los ntawm txoj kev sib txawv yog qhov sib txawv heev, thiab qee qhov muaj qhov sib txawv ob npaug. 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 thiab siab dua qhov hnyav molecular ntawm MC, qhov sib piv ntawm nws cov solubility yuav 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 thickening ntawm mortar, tab sis nws tsis ncaj qha proportional. Qhov siab dua qhov viscosity, qhov viscous ntau dua cov mortar ntub yuav, uas yog, thaum lub sij hawm tsim kho, nws yog manifested li sticking rau scraper thiab siab adhesion rau lub substrate. Tab sis nws tsis muaj txiaj ntsig los ua kom lub zog muaj zog ntawm cov mortar ntub nws tus kheej. Thaum lub sij hawm tsim kho, qhov kev ua tau zoo anti-sag tsis pom tseeb. Ntawm qhov tsis sib xws, qee qhov nruab nrab thiab qis 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 dua ntawm cov cellulose ether ntxiv rau hauv mortar, qhov dej tuav tau zoo dua, thiab qhov viscosity siab dua, qhov dej tuav tau zoo dua.
Hais txog particle loj, qhov finer particle, qhov zoo dua cov dej tuav. Tom qab cov khoom loj ntawm cellulose ether tuaj rau hauv kev sib cuag nrog dej, qhov chaw tam sim ntawd dissolves thiab tsim cov gel los qhwv cov khoom los tiv thaiv cov dej molecules los ntawm kev nkag mus ntxiv. Qee lub sij hawm nws tsis tuaj yeem sib cais thiab yaj txawm tias tom qab lub sij hawm ntev nplawm, tsim cov huab flocculent tov los yog agglomeration. Nws cuam tshuam rau cov dej tuav ntawm cellulose ether, thiab solubility yog ib qho tseem ceeb ntawm kev xaiv cellulose ether.
Fineness kuj yog ib qho tseem ceeb Performance index ntawm methyl cellulose ether. MC siv rau qhuav hmoov mortar yog yuav tsum tau hmoov, nrog dej tsawg, thiab cov fineness kuj yuav tsum tau 20% ~ 60% ntawm particle loj yuav tsum tsawg tshaj li 63um. Lub fineness cuam tshuam rau solubility ntawm methyl cellulose ether. Coarse MC feem ntau yog granular, thiab nws yog ib qho yooj yim rau yaj nyob rau hauv dej tsis muaj agglomeration, tab sis lub dissolution tus nqi qeeb heev, yog li nws tsis haum rau siv nyob rau hauv qhuav hmoov mortar. Nyob rau hauv qhuav hmoov mortar, MC yog dispersed ntawm cementing cov ntaub ntawv xws li aggregate, nplua muab tub lim thiab cement, thiab tsuas yog hmoov zoo txaus yuav zam methyl cellulose ether agglomeration thaum tov nrog dej. Thaum MC ntxiv nrog dej kom yaj cov agglomerates, nws nyuaj heev rau disperse thiab yaj.
Coarse fineness ntawm MC tsis yog tsuas yog khib nyiab, tab sis kuj txo lub zog hauv zos ntawm mortar. Thaum xws li cov hmoov qhuav mortar yog siv rau hauv ib cheeb tsam loj, kev kho ceev ntawm cov hmoov qhuav hauv zos yuav txo qis, thiab cov kab nrib pleb yuav tshwm sim vim lub sijhawm sib txawv. Rau cov tshuaj txau nrog cov khoom siv kho tshuab, qhov yuav tsum tau ua kom zoo yog siab dua vim lub sijhawm sib xyaw luv.
Qhov zoo ntawm MC kuj muaj qee yam cuam tshuam rau nws cov dej tuav. Feem ntau hais lus, rau methyl cellulose ethers nrog tib viscosity tab sis txawv fineness, nyob rau hauv tib qhov sib ntxiv, qhov finer lub finer qhov zoo dua cov dej tuav nyhuv.
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. Txawm li cas los xij, hauv kev siv cov khoom siv tiag tiag, cov hmoov av qhuav feem ntau siv rau cov khoom kub kub ntawm qhov kub siab (siab dua 40 degrees) hauv ntau qhov chaw, xws li sab nrauv phab ntsa putty plastering nyob rau hauv lub hnub nyob rau hauv lub caij ntuj sov, uas feem ntau accelerates curing ntawm cement thiab hardening. qhuav hmoov mortar. Qhov poob ntawm cov dej tuav tus nqi ua rau pom pom tseeb tias ob qho tib si kev ua haujlwm thiab kev ua haujlwm tawg tau cuam tshuam, thiab nws yog qhov tseem ceeb tshwj xeeb los txo qhov cuam tshuam ntawm qhov kub thiab txias hauv qhov xwm txheej no.
Txawm hais tias methyl hydroxyethyl cellulose ether additives yog tam sim no suav hais tias yog nyob rau hauv pem hauv ntej ntawm txoj kev loj hlob, lawv dependence rau kub tseem yuav ua rau tsis muaj zog ntawm kev ua tau zoo ntawm qhuav hmoov mortar. Txawm hais tias tus nqi ntawm methyl hydroxyethyl cellulose yog nce (lub caij ntuj sov mis), kev ua hauj lwm thiab tawg kuj tseem tsis 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, thiab lwm yam, cov dej tuav tau tuaj yeem tswj tau ntawm qhov kub siab dua, kom nws tuaj yeem muab kev ua tau zoo dua hauv cov xwm txheej hnyav.
3. Thickening thiab Thixotropy ntawm Cellulose Ether
Thickening thiab thixotropy ntawm cellulose ether: Qhov thib ob muaj nuj nqi ntawm cellulose ether-thickening nyhuv nyob ntawm: lub degree ntawm polymerization ntawm cellulose ether, kua concentration, shear npaum li cas, kub thiab lwm yam mob. Cov cuab yeej gelling ntawm cov tshuaj yog tshwj xeeb rau alkyl cellulose thiab nws cov derivatives hloov. Cov khoom gelation muaj feem xyuam rau qib ntawm kev hloov pauv, tshuaj concentration thiab additives. Rau hydroxyalkyl hloov derivatives, cov khoom gel kuj muaj feem xyuam nrog kev hloov kho qib ntawm hydroxyalkyl. Rau cov viscosity tsawg MC thiab HPMC, 10%-15% tov tuaj yeem npaj tau, nruab nrab viscosity MC thiab HPMC tuaj yeem npaj 5%-10% tov, thaum siab viscosity MC thiab HPMC tsuas tuaj yeem npaj 2%-3% tov, thiab feem ntau Kev faib tawm viscosity ntawm cellulose ether kuj tau muab qhab nia los ntawm 1% -2% tov.
Siab molecular hnyav cellulose ether muaj cov thickening efficiency. Nyob rau hauv tib lub concentration tov, polymers nrog sib txawv molecular luj muaj sib txawv viscosities. Qib siab. Lub hom phiaj viscosity tsuas tuaj yeem ua tiav los ntawm kev ntxiv ib qho loj ntawm qhov hnyav molecular cellulose ether. Nws viscosity muaj me ntsis nyob ntawm tus nqi shear, thiab lub siab viscosity ncav cuag lub hom phiaj viscosity, thiab qhov yuav tsum tau ntxiv tus nqi yog me me, thiab 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. Cov gel kub ntawm cov tshuaj kuj txo qis linearly nrog qhov nce ntawm cov concentration ntawm cov tshuaj, thiab gels ntawm chav tsev kub tom qab ncav cuag ib tug tej yam concentration. Lub gelling concentration ntawm HPMC yog qhov siab ntawm chav tsev kub.
Kev sib raug zoo kuj tuaj yeem hloov kho los ntawm kev xaiv qhov loj me thiab xaiv cellulose ethers nrog ntau qib kev hloov kho. Qhov kev hloov pauv yog los qhia txog qee qhov kev hloov pauv ntawm pawg hydroxyalkyl ntawm cov pob txha pob txha ntawm MC. Los ntawm kev hloov pauv tus txheeb ze qhov txiaj ntsig ntawm ob tus neeg hloov pauv, uas yog, DS thiab ms txheeb ze hloov pauv qhov txiaj ntsig ntawm pawg methoxy thiab hydroxyalkyl uas peb feem ntau hais. Ntau yam kev ua tau zoo ntawm cellulose ether tuaj yeem tau txais los ntawm kev hloov pauv cov txiaj ntsig sib txawv ntawm ob qhov 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, hloov cov dej-binder piv ntawm cov dej thiab cov cement yog cov nyhuv thickening, qhov ntau npaum li cas, cov dej ntau dua.
Cellulose ethers siv hauv cov khoom siv hauv tsev yuav tsum yaj sai sai hauv dej txias thiab muab qhov tsim nyog rau lub cev. Yog tias muab qee qhov kev txiav tawm, nws tseem dhau los ua flocculent thiab colloidal block, uas yog cov khoom lag luam tsis zoo lossis cov khoom tsis zoo.
Kuj tseem muaj kev sib raug zoo ntawm kev sib xws ntawm cov cement paste thiab ntau npaum li cas ntawm cellulose ether. Cellulose ether tuaj yeem ua kom cov viscosity ntawm mortar zoo heev. Qhov ntau npaum li cas, qhov pom tseeb dua cov nyhuv. High-viscosity cellulose ether aqueous tov muaj siab thixotropy, uas kuj yog ib tug tseem ceeb yam ntxwv ntawm cellulose ether. Aqueous kev daws teeb meem ntawm MC polymers feem ntau muaj pseudoplastic thiab non-thixotropic fluidity hauv qab lawv cov gel kub, tab sis Newtonian ndlwg zog ntawm qis shear tus nqi. Pseudoplasticity nce nrog qhov hnyav molecular lossis concentration ntawm cellulose ether, tsis hais hom kev hloov pauv thiab qib ntawm kev hloov pauv. Yog li ntawd, cellulose ethers ntawm tib qib viscosity, tsis hais MC, HPMC, HEMC, yuav ib txwm qhia tib lub zog rheological ntev npaum li qhov concentration thiab kub nyob twj ywm.
Cov txheej txheem gels yog tsim thaum qhov kub thiab txias, thiab thixotropic ntws heev. High concentration thiab tsawg viscosity cellulose ethers qhia thixotropy txawm nyob rau hauv lub gel kub. Cov cuab yeej no muaj txiaj ntsig zoo rau kev hloov kho ntawm qib thiab sagging hauv kev tsim kho ntawm lub tsev mortar. 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, thiab qhov sib thooj hauv nws cov solubility, uas muaj kev cuam tshuam tsis zoo. ntawm mortar concentration thiab kev tsim kho. Qhov siab dua qhov viscosity, qhov pom tseeb dua cov nyhuv thickening ntawm mortar, tab sis nws tsis yog proportional kiag li. Qee qhov nruab nrab thiab qis viscosity, tab sis hloov kho cellulose ether muaj kev ua tau zoo dua hauv kev txhim kho lub zog ntawm cov khoom ntub dej. Nrog rau qhov nce ntawm viscosity, cov dej tuav ntawm cellulose ether txhim kho. 4. Retardation ntawm cellulose ether
Retardation ntawm cellulose ether: Lub luag haujlwm thib peb ntawm cellulose ether yog ncua cov txheej txheem dej ntawm cov cement. Cellulose ether endows mortar nrog ntau yam khoom muaj txiaj ntsig, thiab tseem txo qis cov dej thaum ntxov ntawm cov cement thiab ncua cov txheej txheem hydration dynamic ntawm cov cement. Qhov no yog qhov tsis zoo rau kev siv tshuaj khib nyiab hauv thaj chaw txias. Cov nyhuv retardation no yog tshwm sim los ntawm adsorption ntawm cellulose ether molecules ntawm hydration khoom xws li CSH thiab ca(OH)2. Vim qhov nce hauv qhov viscosity ntawm cov pore tov, cellulose ether txo qhov kev txav ntawm ions hauv cov tshuaj, yog li ncua cov txheej txheem hydration.
Post lub sij hawm: Feb-04-2023