Nyob rau hauv npaj-mixed mortar, tsuas yog me ntsis ntawm cellulose ether tuaj yeem txhim kho kev ua haujlwm ntawm cov khib nyiab ntub dej. Nws tuaj yeem pom tias cellulose ether yog ib qho tseem ceeb ntxiv uas cuam tshuam rau kev tsim kho ntawm mortar. Xaiv cov cellulose ethers ntawm ntau hom, sib txawv viscosities, sib txawv particle loj, txawv viscosity degrees thiab ntxiv cov nqi kuj muaj qhov sib txawv ntawm kev txhim kho kev ua haujlwm ntawm mortar qhuav. Tam sim no, ntau cov masonry thiab plastering mortars muaj cov dej tsis zoo. Cov dej slurry yuav sib cais tom qab tso nws ib leeg rau ob peb feeb. Yog li ntawd, nws yog ib qho tseem ceeb heev kom ntxiv cellulose ether rau cement mortar. Cia peb saib cov ncauj lus kom ntxaws txog cov haujlwm ntawm cellulose ether hauv cov cement mortar!
1.Cellulose ether-dej tuav
Kev tuav dej yog ib qho cuab yeej tseem ceeb ntawm cellulose ether, thiab nws kuj yog ib qho cuab yeej uas muaj ntau lub tsev tsim khoom qhuav-sib xyaw, tshwj xeeb tshaj yog cov nyob rau yav qab teb thaj av uas muaj qhov kub thiab txias, ua tib zoo saib xyuas. 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 tshuaj khib tshwj xeeb (hloov mortar), nws yog ib qho tseem ceeb thiab tseem ceeb tivthaiv.
Lub viscosity, ntau npaum li cas, ambient kub thiab molecular qauv ntawm cellulose ether muaj kev cuam tshuam zoo rau nws cov dej tuav kev ua haujlwm. Nyob rau tib lub sijhawm, qhov ntau dua qhov viscosity ntawm cellulose ether, qhov dej tuav tau zoo dua; qhov ntau npaum li cas, qhov zoo dua cov dej tuav. Feem ntau, me me ntawm cellulose ether tuaj yeem txhim kho cov dej tuav tus nqi ntawm mortar. Thaum cov koob tshuaj nce mus txog ib theem, qhov sib txawv ntawm cov dej khaws cia qeeb qeeb; Cov dej tuav ntawm cellulose ether feem ntau txo qis nrog qhov nce ntawm qhov kub thiab txias, tab sis qee qhov hloov pauv cellulose ethers kuj muaj cov dej zoo khaws cia hauv qhov kub thiab txias; cellulose ethers nrog qis hloov degree muaj kev tuav dej zoo dua.
Cov pab pawg hydroxyl ntawm cov cellulose ether molecules thiab cov pa atoms ntawm ether bonds yuav tsim hydrogen bonds nrog dej molecules, tig dej dawb rau hauv cov dej khi, yog li ua lub luag haujlwm zoo hauv dej tuav; Kev sib koom ua ke ntawm cov dej molecules thiab cellulose ether molecular chains tso cai rau cov dej molecules nkag mus rau sab hauv ntawm cellulose ether macromolecular saw thiab yuav raug txwv tsis pub muaj zog, yog li tsim cov dej dawb thiab dej entangled, yog li txhim kho cov dej tuav ntawm cov cement slurry; cellulose ether txhim kho lub zog rheological, ntxeem tau network qauv thiab osmotic siab ntawm cov cement slurry tshiab, los yog zaj duab xis-forming zog ntawm cellulose ether cuam tshuam cov diffusion ntawm dej.
2.Cellulose ether-thickening thiab thixotropy
Cellulose ether muab cov ntaub ntub dej zoo heev viscosity, uas tuaj yeem ua rau muaj peev xwm ua kom muaj peev xwm sib txuas ntawm cov khib nyiab ntub thiab txheej txheej, thiab txhim kho kev ua haujlwm ntawm cov tshuaj khib nyiab. Nws yog dav siv nyob rau hauv plastering mortar, pobzeb bonding mortar thiab sab nrauv phab ntsa rwb thaiv tsev systems. Cov nyhuv thickening ntawm cellulose ether kuj tuaj yeem ua rau kom muaj kev sib txawv ntawm cov ntaub ntawv tshiab, tiv thaiv cov khoom delamination, sib cais thiab los ntshav, thiab tuaj yeem siv rau hauv fiber ntau pob zeb, underwater pob zeb thiab nws tus kheej-compacting pob zeb.
Cov nyhuv thickening ntawm cellulose ether ntawm cov khoom siv cement los ntawm cov viscosity ntawm cellulose ether tov. Nyob rau hauv tib lub sijhawm, qhov siab dua qhov viscosity ntawm cellulose ether, qhov zoo dua qhov viscosity ntawm cov khoom hloov cement-based. Txawm li cas los xij, yog tias qhov viscosity siab dhau lawm, nws yuav cuam tshuam rau cov dej ntws thiab kev ua haujlwm ntawm cov khoom siv (xws li lo rau lub plaster riam). Self-leveling mortars thiab self-compacting pob zeb uas yuav tsum tau muaj fluidity yuav tsum muaj tsawg viscosity ntawm cellulose ether. Tsis tas li ntawd, cov nyhuv thickening ntawm cellulose ethers tsub kom cov dej thov ntawm cement-based cov ntaub ntawv thiab nce mortar yields.
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 methylcellulose feem ntau muaj pseudoplastic, uas tsis yog-thixotropic ndlwg zog hauv qab lawv gel kub, tab sis nthuav tawm Newtonian ndlwg zog ntawm tus nqi qis. Pseudoplasticity nce nrog qhov nce hauv qhov hnyav ntawm molecular lossis concentration ntawm cellulose ether, tsis hais hom thiab qib ntawm kev hloov pauv ntawm qhov hloov pauv. Yog li ntawd, cellulose ethers ntawm tib qib viscosity, txawm MC, HPMC, los yog HEMC, yuav yeej ib txwm nthuav tawm cov khoom rheological tib lub sij hawm ntev npaum li qhov concentration thiab kub nyob twj ywm. Thaum qhov kub thiab txias nce, cov txheej txheem gel yog tsim thiab siab thixotropic ntws tshwm sim.
Cov concentrations siab thiab qis viscosity cellulose ethers muaj thixotropy txawm tias qis dua qhov kub ntawm gel. Cov cuab yeej no muaj txiaj ntsig zoo hauv kev kho cov theem thiab sagging ntawm lub tsev mortar thaum tsim kho. Nws yuav tsum raug sau tseg 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 sib txheeb molecular hnyav ntawm cellulose ether, thiab nws solubility txo qis raws li, uas muaj kev cuam tshuam tsis zoo. lub mortar concentration thiab kev tsim kho.
3.Cellulose ether-air entraining nyhuv
Cellulose ether muaj qhov tseem ceeb ntawm huab cua nkag mus rau cov khoom siv cement-based tshiab. Cellulose ether muaj ob pawg hydrophilic (hydroxyl pawg, ether pawg) thiab pawg hydrophobic (methyl pawg, qab zib rings). Nws yog ib qho surfactant nrog kev ua haujlwm saum npoo thiab yog li muaj cov nyhuv cua nkag. Cov huab cua entraining nyhuv ntawm cellulose ether yuav tsim ib tug "pob" nyhuv, uas yuav txhim khu kev ua hauj lwm ntawm cov ntaub ntawv tshiab sib xyaw, xws li nce cov yas thiab smoothness ntawm mortar thaum lub sij hawm ua hauj lwm, uas yog zoo rau cov paving ntawm mortar; nws tseem yuav ua rau kom cov khoom siv khib nyiab thiab txo cov nqi ntawm cov tshuaj khib nyiab; tab sis nws yuav ua rau kom cov porosity ntawm cov ntaub ntawv hardened thiab txo lawv cov khoom siv xws li lub zog thiab elastic modulus.
Raws li ib tug surfactant, cellulose ether kuj muaj ib tug ntub dej los yog lubricating nyhuv ntawm cov cement hais, uas ua ke nrog nws cov huab cua entraining nyhuv tsub kom lub fluidity ntawm cement-based cov ntaub ntawv, tab sis nws thickening nyhuv yuav txo cov fluidity. Cov nyhuv ntawm cellulose ether ntawm fluidity ntawm cov ntaub ntawv cement-based yog kev sib xyaw ntawm plasticization thiab thickening teebmeem. Feem ntau hais lus, thaum lub cellulose ether ntau npaum li cas tsawg heev, nws tsuas yog manifests li plasticizing los yog dej txo cov nyhuv; Thaum noj ntau npaum li cas, cov nyhuv thickening ntawm cellulose ether nce sai, thiab nws cov huab cua nkag mus rau hauv cov nyhuv zoo li saturation, yog li nws manifests li thickening nyhuv los yog nce dej thov.
4.Cellulose ether-retarding nyhuv
Cellulose ether yuav ncua sij hawm teem caij ntawm cov cement paste los yog mortar thiab ncua lub cement hydration dynamics, uas yog qhov zoo los ua kom lub sijhawm ua haujlwm ntawm cov khoom sib xyaw tshiab thiab txhim kho lub sij hawm-raws li qhov poob ntawm mortar sib xws thiab cov pob zeb tawg, tab sis nws kuj tseem tuaj yeem ua haujlwm. ncua kev txhim kho kev txhim kho.
Post lub sij hawm: Sep-24-2024