Cov pab pawg hydroxyl rau ntawmcellulose etherCov molecules thiab cov pa oxygen ntawm cov ether bonds yuav tsim cov hydrogen bonds nrog cov dej molecules, hloov cov dej dawb mus rau hauv dej khi, yog li ua lub luag haujlwm zoo hauv kev khaws dej; qhov sib txawv ntawm cov dej molecules thiab cellulose ether molecular saw hlau tso cai rau cov dej molecules nkag mus rau sab hauv ntawm cellulose ether macromolecular saw hlau thiab raug rau cov kev txwv muaj zog, yog li tsim cov dej dawb thiab dej entangled, uas txhim kho kev khaws dej ntawm cov cement slurry; cellulose ether txhim kho cov khoom rheological, porous network qauv thiab osmotic siab ntawm cov cement slurry tshiab lossis cov khoom tsim zaj duab xis ntawm cellulose ether cuam tshuam kev sib kis ntawm dej.
Qhov kev khaws dej ntawm cellulose ether nws tus kheej los ntawm qhov solubility thiab dehydration ntawm cellulose ether nws tus kheej. Lub peev xwm hydration ntawm hydroxyl pawg ib leeg tsis txaus los them rau cov hydrogen bonds muaj zog thiab van der Waals quab yuam ntawm cov molecules, yog li nws tsuas yog swells tab sis tsis yaj hauv dej. Thaum substituents raug qhia rau hauv cov saw molecular, tsis yog tsuas yog cov substituents rhuav tshem cov hydrogen saw, tab sis kuj tseem muaj cov interchain hydrogen bonds raug rhuav tshem vim yog qhov wedging ntawm cov substituents ntawm cov saw sib ze. Qhov loj dua cov substituents, qhov ntau dua qhov deb ntawm cov molecules, thiab qhov ntau dua qhov cuam tshuam ntawm kev rhuav tshem cov hydrogen bonds. Tom qab cellulose lattice swells, cov tshuaj nkag mus, thiab cellulose ether ua dej-soluble, tsim cov tshuaj viscosity siab, uas tom qab ntawd ua lub luag haujlwm hauv kev khaws dej.
Cov yam tseem ceeb uas cuam tshuam rau kev ua haujlwm ntawm dej:
Viscosity: Qhov viscosity ntawm cellulose ether ntau dua, qhov zoo dua qhov kev ua tau zoo ntawm kev khaws dej, tab sis qhov viscosity siab dua, qhov hnyav molecular ntawm cellulose ether siab dua, thiab nws cov solubility txo qis raws li, uas muaj qhov cuam tshuam tsis zoo rau qhov concentration thiab kev ua tau zoo ntawm mortar. Feem ntau hais lus, rau tib yam khoom, cov txiaj ntsig viscosity ntsuas los ntawm ntau txoj kev sib txawv yog txawv heev, yog li thaum piv rau viscosity, nws yuav tsum tau ua tiav ntawm tib txoj kev sim (suav nrog kub, rotor, thiab lwm yam).
Ntxiv ntau npaum li cas: Qhov ntau npaum li cas ntawm cellulose ether ntxiv rau hauv cov mortar, qhov zoo dua qhov kev ua tau zoo ntawm kev khaws dej. Feem ntau, me me ntawm cellulose ether tuaj yeem txhim kho qhov ceev ntawm cov mortar. Thaum qhov ntau npaum li cas mus txog ib qib twg, qhov sib txawv ntawm kev nce qhov ceev ntawm kev khaws dej qeeb qeeb.
Qhov zoo ntawm cov khoom me me: Cov khoom me me dua, qhov zoo dua qhov khaws dej. Thaum cov khoom loj ntawm cellulose ether kov dej, qhov chaw tam sim ntawd yaj thiab tsim cov gel los qhwv cov khoom kom tiv thaiv cov dej molecules kom tsis txhob nkag mus. Qee zaum, txawm tias kev do ntev ntev tsis tuaj yeem ua tiav kev sib kis thiab kev yaj sib xws, tsim cov kua flocculent turbid lossis agglomeration, uas cuam tshuam loj heev rau kev khaws dej ntawm cellulose ether. Kev yaj yog ib qho ntawm cov yam tseem ceeb rau kev xaiv cellulose ether. Kev yaj kuj yog ib qho cim qhia kev ua tau zoo tseem ceeb ntawm methyl cellulose ether. Kev yaj cuam tshuam rau kev yaj ntawm methyl cellulose ether. Coarser MC feem ntau yog granular thiab tuaj yeem yaj tau yooj yim hauv dej yam tsis muaj agglomeration, tab sis qhov nrawm yaj qeeb heev thiab nws tsis haum rau siv hauv cov mortar qhuav.
Kub: Thaum qhov kub thiab txias ib puag ncig nce siab, qhov khaws cia dej ntawm cellulose ethers feem ntau txo qis, tab sis qee cov cellulose ethers hloov kho kuj muaj qhov khaws cia dej zoo nyob rau hauv qhov kub thiab txias siab; thaum qhov kub thiab txias nce siab, qhov dej ntawm cov polymers tsis muaj zog, thiab cov dej ntawm cov saw hlau raug ntiab tawm. Thaum qhov dej qhuav txaus, cov molecules pib sib sau ua ke los tsim cov qauv network peb-seem gel.
Cov qauv molecular: Cellulose ethers nrog qis dua kev hloov pauv muaj kev khaws cia dej zoo dua.
Thickening thiab thixotropy
Ua kom tuab:
Cov nyhuv rau kev muaj peev xwm sib txuas thiab kev ua haujlwm tiv thaiv kev sagging: Cellulose ethers muab cov mortar ntub dej zoo heev viscosity, uas tuaj yeem ua rau muaj peev xwm sib txuas ntawm cov mortar ntub dej nrog cov txheej hauv paus thiab txhim kho kev ua haujlwm tiv thaiv kev sagging ntawm mortar. Nws yog dav siv hauv plastering mortar, vuas vov tsev thiab phab ntsa sab nraud rwb thaiv tsev system 3.
Cov nyhuv rau cov khoom siv sib xws: Cov nyhuv tuab ntawm cellulose ethers kuj tseem tuaj yeem ua rau muaj peev xwm tiv thaiv kev tawg thiab kev sib xws ntawm cov khoom sib xyaw tshiab, tiv thaiv cov khoom siv stratification, kev sib cais thiab dej seepage, thiab tuaj yeem siv rau hauv cov fiber ntau, cov pob zeb hauv qab dej thiab cov pob zeb compacting tus kheej.
Qhov chaw thiab kev cuam tshuam ntawm cov nyhuv thickening: Cov nyhuv thickening ntawm cellulose ether rau cov ntaub ntawv cement los ntawm qhov viscosity ntawm cellulose ether kua. Nyob rau hauv tib lub xeev, qhov siab dua qhov viscosity ntawm cellulose ether, qhov zoo dua qhov viscosity ntawm cov ntaub ntawv cement hloov kho, tab sis yog tias qhov viscosity siab dhau, nws yuav cuam tshuam rau qhov fluidity thiab kev ua haujlwm ntawm cov khoom (xws li lo rau ntawm rab riam plastering). Cov mortar self-leveling thiab cov pob zeb self-compacting nrog cov kev xav tau fluidity siab xav tau qhov viscosity qis heev ntawm cellulose ether. Tsis tas li ntawd, qhov thickening ntawm cellulose ether kuj tseem yuav ua rau kom muaj dej ntau ntxiv ntawm cov ntaub ntawv cement thiab ua rau cov mortar tso zis ntau ntxiv.
Thixotropy:
Cov kua dej cellulose ether uas muaj viscosity siab muaj thixotropy siab, uas kuj yog ib qho tseem ceeb ntawm cellulose ether. Cov kua dej ntawm methyl cellulose feem ntau muaj pseudoplasticity thiab non-thixotropic fluidity qis dua nws qhov kub gel, tab sis qhia txog cov khoom ntws Newtonian ntawm qhov nrawm qis. Pseudoplasticity nce nrog qhov nce ntawm cellulose ether molecular hnyav lossis concentration, thiab tsis muaj dab tsi ua rau hom substituent thiab degree ntawm kev hloov pauv. Yog li ntawd, cellulose ethers ntawm tib qib viscosity, txawm tias MC, HPMC, lossis HEMC, ib txwm qhia tib yam rheological khoom ntev li ntev tau qhov concentration thiab kub tseem nyob ruaj khov. Thaum qhov kub nce, ib qho gel qauv tsim, thiab qhov ntws thixotropic siab tshwm sim. Cellulose ethers nrog qhov concentration siab thiab viscosity qis qhia thixotropy txawm tias qis dua qhov kub gel. Cov khoom no muaj txiaj ntsig zoo rau kev kho qhov leveling thiab sagging ntawm lub tsev mortar thaum lub sijhawm tsim kho.
Kev nkag mus rau hauv huab cua
Lub hauv paus ntsiab lus thiab cov nyhuv rau kev ua haujlwm: Cellulose ether muaj cov nyhuv tseem ceeb rau huab cua nkag rau cov khoom siv cement tshiab. Cellulose ether muaj ob qho tib si hydrophilic pawg (hydroxyl pawg, ether pawg) thiab hydrophobic pawg (methyl pawg, glucose rings). Nws yog ib qho surfactant nrog kev ua haujlwm ntawm qhov chaw, yog li muaj cov nyhuv rau huab cua nkag. Cov nyhuv rau huab cua nkag yuav tsim cov nyhuv pob, uas tuaj yeem txhim kho kev ua haujlwm ntawm cov khoom sib xyaw tshiab, xws li ua kom cov yas thiab du ntawm cov mortar thaum lub sijhawm ua haujlwm, uas yog qhov zoo rau kev nthuav dav ntawm cov mortar; nws tseem yuav ua rau cov zis ntawm cov mortar thiab txo cov nqi tsim khoom ntawm cov mortar.
Cov nyhuv rau cov khoom siv kho tshuab: Cov nyhuv ntawm huab cua nkag yuav ua rau kom cov porosity ntawm cov khoom tawv thiab txo nws cov khoom siv kho tshuab xws li lub zog thiab elastic modulus.
Cov nyhuv ntawm kev ua kua: Raws li surfactant, cellulose ether kuj muaj cov nyhuv ntub lossis lubricating rau cov cement me me, uas ua ke nrog nws cov nyhuv entraining cua ua rau cov kua ntawm cov cement-based cov ntaub ntawv ua kua ntau ntxiv, tab sis nws cov nyhuv thickening yuav txo qhov fluidity. Cov nyhuv ntawm cellulose ether rau cov kua ntawm cov cement-based cov ntaub ntawv yog kev sib xyaw ua ke ntawm cov yas thiab cov nyhuv thickening. Feem ntau hais lus, thaum cov cellulose ether koob tshuaj tsawg heev, nws feem ntau pom tias yog cov yas lossis cov nyhuv txo dej; thaum cov koob tshuaj siab, cov nyhuv thickening ntawm cellulose ether nce sai, thiab nws cov nyhuv entraining cua feem ntau yuav saturated, yog li nws pom tias yog cov thickening lossis nce dej thov.
Lub sijhawm tshaj tawm: Lub Kaum Ob Hlis-23-2024