Nyob rau hauv npaj sib xyaw mortar, tsuav yog me ntsis 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.
Kev xaiv ntawm ntau yam sib txawv, txawv viscosities, sib txawv particle loj, txawv degrees ntawm viscosity thiab ntxiv ntawm cellulose ethers kuj muaj qhov sib txawv ntawm kev txhim kho kev ua haujlwm ntawm cov hmoov qhuav mortar. Tam sim no, ntau cov masonry thiab plastering mortars muaj cov dej tsis zoo, thiab cov dej slurry yuav sib cais tom qab ob peb feeb ntawm kev sawv, yog li nws tseem ceeb heev uas yuav tau ntxiv cellulose ether rau cement mortar.
Cia peb saib ze dua ntawm lub luag haujlwm ntawm cellulose ether hauv cement mortar!
1. Cellulose ether - dej tuav
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. 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 kev tsim cov mortar 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, ib qho me me ntawm cellulose ether tuaj yeem txhim kho cov dej tuav ntawm mortar. Thaum qhov ntau npaum li cas nce mus txog qhov tseeb Thaum cov qib dej tuav tau nce, qhov sib txawv ntawm cov dej tuav tau qeeb; Thaum lub ambient kub nce, cov dej tuav ntawm cellulose ether feem ntau txo qis, tab sis qee qhov hloov kho cellulose ethers kuj muaj cov dej tuav zoo dua nyob rau hauv qhov kub thiab txias; fibers nrog qis dua ntawm kev hloov Vegan ether muaj cov dej tuav tau zoo dua.
Cov pab pawg hydroxyl ntawm cellulose ether molecule thiab cov pa atom ntawm ether daim ntawv cog lus yuav koom nrog cov dej molecule los tsim ib daim ntawv cog lus hydrogen, tig cov dej dawb rau hauv cov dej khi, yog li ua lub luag haujlwm zoo hauv dej tuav; Cov dej molecule thiab cellulose ether molecular saw Interdiffusion tso cai rau cov dej molecules nkag mus rau sab hauv ntawm cellulose ether macromolecular saw thiab muaj zog binding rog, yog li tsim dej dawb, entangled dej, thiab txhim kho cov dej tuav ntawm cement slurry; cellulose ether txhim kho cov cement slurry tshiab Cov khoom siv rheological, cov qauv ntxeem tau ntawm lub network thiab osmotic siab lossis cov yeeb yaj kiab tsim cov khoom ntawm cellulose ether cuam tshuam cov dej ntws.
2. Cellulose ether – thickening thiab thixotropy
Cellulose ether endows cov ntaub ntub dej nrog cov viscosity zoo heev, uas tuaj yeem ua rau muaj peev xwm ua kom muaj peev xwm sib txuas ntawm cov mortar ntub thiab cov txheej txheej, thiab txhim kho kev ua haujlwm ntawm cov tshuaj khib nyiab. Nws yog dav siv nyob rau hauv plastering mortar, cib bonding mortar thiab sab nrauv phab ntsa rwb thaiv tsev system. Cov nyhuv thickening ntawm cellulose ether kuj tuaj yeem ua rau kom muaj peev xwm tiv thaiv kev tawg thiab kev sib xyaw ntawm cov khoom sib xyaw tshiab, tiv thaiv cov khoom delamination, 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 kua. Nyob rau tib lub sijhawm, qhov siab dua ntawm cov viscosity ntawm cellulose ether, qhov viscosity zoo dua ntawm cov khoom siv cement-based, tab sis yog tias cov viscosity siab dhau lawm, nws yuav cuam tshuam rau cov dej ntws thiab kev ua haujlwm ntawm cov khoom siv (xws li sticking plastering riam. ). Self-leveling mortar thiab self-compacting qhob, uas yuav tsum tau muaj fluidity, yuav tsum tau tsawg viscosity ntawm cellulose ether. Tsis tas li ntawd, cov nyhuv thickening ntawm cellulose ether yuav ua rau kom cov dej xav tau ntawm cov ntaub ntawv cement-based thiab ua kom cov qoob loo ntau ntxiv.
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 methyl cellulose feem ntau muaj pseudoplastic thiab non-thixotropic fluidity hauv qab nws cov gel kub, tab sis qhia Newtonian fluidity ntawm tsawg 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 yam rheological zog 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.
3. Cellulose ether-air-entraining nyhuv
Cellulose ether muaj qhov pom tseeb huab cua nkag mus rau cov khoom siv cement-based tshiab. Cellulose ether muaj ob pawg hydrophilic (hydroxyl pawg, ether pawg) thiab hydrophobic pawg (methyl pawg, qabzib rings), thiab yog ib qho surfactant nrog cov dej num saum npoo, yog li muaj huab cua nkag mus. Cov huab cua-entraining nyhuv ntawm cellulose ether yuav tsim ib tug "pob", uas yuav txhim khu kev ua hauj lwm ntawm cov khoom sib xyaw tshiab, xws li ua kom cov yas thiab smoothness ntawm mortar thaum lub sij hawm ua hauj lwm, uas yog conducive mus rau kis tau tus kab mob. ; nws kuj yuav ua rau kom cov zis ntawm cov mortar, txo cov nqi ntawm cov mortar; tab sis nws yuav ua rau kom cov porosity ntawm cov khoom hardened thiab txo nws 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 rau kom lub fluidity ntawm cement-based cov ntaub ntawv ua ke nrog nws cov huab cua-entraining nyhuv, tab sis nws thickening nyhuv yuav txo fluidity. Cov nyhuv ntawm fluidity yog ua ke ntawm plasticizing thiab thickening teebmeem. Feem ntau hais lus, thaum cov ntsiab lus ntawm cellulose ether tsawg heev, qhov kev ua haujlwm tseem ceeb yog plasticization lossis dej txo; Thaum cov ntsiab lus siab, cov nyhuv thickening ntawm cellulose ether nce sai, thiab nws cov huab cua-entraining nyhuv nyhav saturated. Yog li nws pom tau tias yog cov nyhuv thickening lossis nce hauv cov dej xav tau.
4. Cellulose ether - cov nyhuv retarding
Cellulose ether yuav ncua sij hawm teem caij ntawm cov cement paste los yog mortar, thiab ncua lub hydration kinetics ntawm cov cement, uas yog qhov zoo los txhim kho lub sijhawm ua haujlwm ntawm cov khoom sib xyaw tshiab, txhim kho qhov sib xws ntawm mortar thiab poob ntawm cov pob zeb tawg thaum lub sij hawm, tab sis yuav kuj ua rau ncua kev tsim kho.
Post lub sij hawm: Jun-02-2023