Qhov cuam tshuam ntawm qhov kub thiab txias ntawm kev ua haujlwm ntawm cellulose ether hloov gypsum

Kev ua tau zoo ntawm cellulose ether hloov gypsum ntawm qhov sib txawv ambient kub yog txawv heev, tab sis nws cov txheej txheem tsis meej. Cov teebmeem ntawm cellulose ether ntawm rheological tsis thiab dej tuav ntawm gypsum slurry ntawm qhov sib txawv ambient kub tau kawm. Lub hydrodynamic txoj kab uas hla ntawm cellulose ether nyob rau hauv cov kua theem yog ntsuas los ntawm dynamic lub teeb scattering txoj kev, thiab lub zog mechanism tau tshawb. Cov txiaj ntsig tau pom tias cellulose ether muaj cov dej zoo khaws cia thiab cov nyhuv thickening ntawm gypsum. Nrog rau qhov nce ntawm cellulose ether cov ntsiab lus, viscosity ntawm slurry nce thiab cov dej khaws cia muaj peev xwm nce. Txawm li cas los xij, nrog qhov nce ntawm qhov kub thiab txias, cov dej tuav lub peev xwm ntawm kev hloov kho gypsum slurry txo qis rau qee yam, thiab cov rheological tsis hloov pauv. Xav txog tias lub koom haum cellulose ether colloid tuaj yeem ua tiav cov dej tuav los ntawm kev thaiv cov dej thauj channel, qhov kub thiab txias tuaj yeem ua rau kev tawg ntawm lub koom haum loj ntim tsim los ntawm cellulose ether, yog li txo cov dej tuav thiab kev ua haujlwm ntawm kev hloov gypsum.

Cov lus tseem ceeb:gypsum; Cellulose ether; Kub; Kev tuav dej; rheology

0. Taw qhia

Gypsum, raws li ib yam khoom ntawm ib puag ncig tus phooj ywg nrog kev tsim kho thiab lub cev zoo, yog siv dav hauv cov haujlwm kho kom zoo nkauj. Nyob rau hauv daim ntawv thov ntawm gypsum raws li cov ntaub ntawv, cov dej tuav cov neeg sawv cev feem ntau yog ntxiv los hloov cov slurry los tiv thaiv cov dej poob hauv cov txheej txheem ntawm hydration thiab hardening. Cellulose ether yog cov dej khaws cia ntau tshaj plaws tam sim no. Vim tias ionic CE yuav hnov ​​​​mob nrog Ca2+, feem ntau siv tsis-ionic CE, xws li: hydroxypropyl methyl cellulose ether, hydroxyethyl methyl cellulose ether thiab methyl cellulose ether. Nws yog ib qho tseem ceeb los kawm txog cov khoom ntawm cellulose ether hloov gypsum rau kev siv gypsum zoo dua hauv kev kho kom zoo nkauj engineering.

Cellulose ether yog lub siab molecular compound tsim los ntawm cov tshuaj tiv thaiv ntawm alkali cellulose thiab etherifying tus neeg saib xyuas nyob rau hauv tej yam kev mob. Cov nonionic cellulose ether siv nyob rau hauv kev tsim kho engineering muaj zoo dispersion, dej tuav, bonding thiab thickening nyhuv. Qhov sib ntxiv ntawm cellulose ether muaj qhov pom tseeb heev ntawm cov dej tuav ntawm gypsum, tab sis qhov khoov thiab compressive lub zog ntawm gypsum hardened lub cev kuj txo me ntsis nrog qhov nce ntawm qhov sib ntxiv. Qhov no yog vim hais tias cellulose ether muaj ib tug tej yam huab cua entraining nyhuv, uas yuav qhia npuas nyob rau hauv cov txheej txheem ntawm slurry mixing, yog li txo cov neeg kho tshuab zog ntawm lub cev hardened. Nyob rau tib lub sijhawm, cellulose ether ntau dhau yuav ua rau gypsum sib xyaw ua ke, ua rau nws txoj kev tsim kho.

Cov txheej txheem hydration ntawm gypsum tuaj yeem muab faib ua plaub theem: kev sib cais ntawm calcium sulfate hemihydrate, crystallization nucleation ntawm calcium sulfate dihydrate, kev loj hlob ntawm crystalline nucleus thiab tsim cov qauv crystalline. Nyob rau hauv cov txheej txheem hydration ntawm gypsum, hydrophilic functional pab pawg neeg ntawm cellulose ether adsorbing nyob rau saum npoo ntawm gypsum hais yuav kho ib feem ntawm dej molecules, yog li ncua lub nucleation txheej txheem ntawm gypsum hydration thiab ncua lub sij hawm teem ntawm gypsum. Los ntawm kev soj ntsuam SEM, Mroz pom tias txawm hais tias muaj cellulose ether ncua kev loj hlob ntawm cov muaju, tab sis nce qhov sib tshooj thiab sib sau ua ke ntawm cov muaju.

Cellulose ether muaj cov pab pawg hydrophilic kom nws muaj qee yam hydrophilicity, polymer ntev saw interconnecting nrog ib leeg kom nws muaj viscosity siab, kev sib cuam tshuam ntawm ob ua rau cellulose muaj cov dej zoo khaws cov thickening nyhuv ntawm gypsum mix. Bulichen piav qhia txog cov dej tuav cov txheej txheem ntawm cellulose ether hauv cov cement. Thaum sib tov qis, cellulose ether adsorb ntawm cov cement rau kev nqus dej intramolecular thiab nrog rau o kom ua tiav cov dej tuav. Lub sijhawm no, kev tuav dej tsis zoo. Kev siv ntau ntau, cellulose ether yuav tsim ntau pua nanometers rau ob peb microns ntawm colloidal polymer, zoo thaiv cov gel hauv lub qhov, kom ua tiav cov dej tuav tau zoo. Cov txheej txheem ua haujlwm ntawm cellulose ether hauv gypsum yog tib yam li hauv cov cement, tab sis ntau dua SO42- concentration hauv cov kua dej theem ntawm gypsum slurry yuav ua rau cov dej tuav cov cellulose tsis muaj zog.

Raws li cov ntsiab lus saum toj no, nws tuaj yeem pom tias qhov kev tshawb fawb tam sim no ntawm cellulose ether hloov gypsum feem ntau tsom rau cov txheej txheem dej ntawm cellulose ether ntawm gypsum mix, dej tuav cov khoom, txhua yam khoom thiab microstructure ntawm lub cev tawv, thiab cov txheej txheem ntawm cellulose ether. tuav dej. Txawm li cas los xij, txoj kev tshawb fawb txog kev cuam tshuam ntawm cellulose ether thiab gypsum slurry ntawm qhov kub thiab txias tseem tsis txaus. Cellulose ether aqueous kua yuav gelatinize ntawm qhov kub thiab txias. Raws li qhov kub thiab txias, qhov viscosity ntawm cellulose ether aqueous tov yuav maj mam txo. Thaum lub gelatinization kub mus txog, cellulose ether yuav precipitated rau hauv dawb gel. Piv txwv li, nyob rau hauv lub caij ntuj sov kev tsim kho, lub ambient kub yog siab, lub thermal gel zog ntawm cellulose ether yog khi ua rau cov kev hloov nyob rau hauv lub workability ntawm hloov gypsum slurry. Txoj haujlwm no tshawb txog qhov tshwm sim ntawm qhov kub thiab txias ntawm kev ua haujlwm ntawm cellulose ether hloov cov khoom siv gypsum los ntawm kev sim ua haujlwm, thiab muab kev taw qhia rau kev siv tswv yim ntawm cellulose ether hloov gypsum.

1. Kev sim

1.1 Cov khoom siv raw

Gypsum yog β-hom ntuj tsim gypsum muab los ntawm Beijing Ecological Home Group.

Cellulose ether xaiv los ntawm Shandong Yiteng Group hydroxypropyl methyl cellulose ether, cov khoom specifications rau 75,000 mPa·s, 100,000 mPa·s thiab 200000mPa·s, gelation kub siab tshaj 60 ℃. Citric acid tau xaiv ua gypsum retarder.

1.2 Rheology Test

Cov cuab yeej ntsuas rheological siv yog RST⁃CC rheometer tsim los ntawm BROOKFIELD USA. Rheological tsis xws li yas viscosity thiab yield shear stress ntawm gypsum slurry tau txiav txim los ntawm MBT⁃40F⁃0046 qauv thawv thiab CC3⁃40 rotor, thiab cov ntaub ntawv tau ua tiav los ntawm RHE3000 software.

Cov yam ntxwv ntawm gypsum mix ua raws li tus cwj pwm rheological ntawm Bingham kua, uas feem ntau yog kawm siv Bingham qauv. Txawm li cas los xij, vim yog pseudoplasticity ntawm cellulose ether ntxiv rau polymer-hloov gypsum, cov slurry sib tov feem ntau nthuav tawm cov cuab yeej shear thinning. Hauv qhov no, hloov kho Bingham (M⁃B) qauv tuaj yeem piav qhia tau zoo dua ntawm rheological nkhaus ntawm gypsum. Txhawm rau kawm txog kev deformation ntawm gypsum, txoj haujlwm no kuj siv Herschel⁃Bulkley (H⁃B) qauv.

1.3 Kev ntsuas dej ruaj khov

Cov txheej txheem xeem xa mus rau GB / T28627⁃2012 Plastering Plaster. Thaum lub sij hawm sim nrog kub raws li qhov sib txawv, lub gypsum tau preheated 1h ua ntej ntawm qhov sib xws ntawm qhov kub hauv qhov cub, thiab cov dej sib xyaw siv hauv qhov kev sim tau preheated 1h nyob rau hauv qhov sib xws hauv qhov kub thiab txias dej da dej, thiab cov cuab yeej siv. tau preheated.

1.4 Hydrodynamic txoj kab uas hla

Lub hydrodynamic txoj kab uas hla (D50) ntawm HPMC polymer koom haum nyob rau hauv cov kua theem tau ntsuas siv lub dynamic lub teeb tawg particle loj analyzer (Malvern Zetasizer NanoZS90).

2. Cov txiaj ntsig thiab kev sib tham

2.1 Rheological zog ntawm HPMC hloov kho gypsum

Pom tseeb viscosity yog qhov sib piv ntawm kev ntxhov siab rau shear tus nqi ua haujlwm ntawm cov kua dej thiab yog qhov ntsuas qhov ntsuas qhov ntws ntawm cov kua dej uas tsis yog-Newtonian. Lub meej viscosity ntawm hloov gypsum slurry hloov nrog cov ntsiab lus ntawm cellulose ether nyob rau hauv peb txawv specifications (75000mPa·s, 100,000mpa·s thiab 200000mPa·s). Qhov ntsuas kub yog 20 ℃. Thaum lub shear tus nqi ntawm rheometer yog 14min-1, nws tuaj yeem pom tias cov viscosity ntawm gypsum slurry nce nrog kev nce ntawm HPMC kev koom ua ke, thiab siab dua HPMC viscosity yog, qhov siab dua qhov viscosity ntawm hloov gypsum slurry yuav. Qhov no qhia tau hais tias HPMC muaj pom tseeb thickening thiab viscosification nyhuv ntawm gypsum slurry. Gypsum slurry thiab cellulose ether yog cov khoom uas muaj viscosity. Nyob rau hauv kev hloov kho gypsum mix, cellulose ether yog adsorbed rau ntawm qhov chaw ntawm gypsum hydration khoom, thiab lub network tsim los ntawm cellulose ether thiab lub network tsim los ntawm cov gypsum mix yog interwoven, uas ua rau "superposition effect", uas ho txhim kho lub zuag qhia tag nrho viscosity. cov ntaub ntawv hloov kho gypsum.

Lub shear ⁃ kev nyuaj siab nkhaus ntawm ntshiab gypsum (G⁃H) thiab hloov kho gypsum (G⁃H) muab tshuaj txhuam doped nrog 75000mPa·s-HPMC, raws li inferred los ntawm lub revised Bingham (M⁃B) qauv. Nws tuaj yeem pom tau tias nrog kev nce ntawm cov nqi shear, lub shear stress ntawm cov sib tov kuj nce. Cov yas viscosity (ηp) thiab yield shear stress (τ0) qhov tseem ceeb ntawm cov ntshiab gypsum thiab HPMC hloov gypsum ntawm qhov kub sib txawv tau txais.

Los ntawm cov yas viscosity (ηp) thiab yield shear stress (τ0) qhov tseem ceeb ntawm cov ntshiab gypsum thiab HPMC hloov gypsum ntawm qhov kub thiab txias, nws tuaj yeem pom tias qhov kev ntxhov siab ntawm HPMC hloov kho gypsum yuav txo qis tsis tu ncua nrog qhov nce ntawm qhov kub thiab txias, thiab yield. Kev ntxhov siab yuav txo qis 33% ntawm 60 ℃ piv nrog 20 ℃. Los ntawm kev soj ntsuam cov yas viscosity nkhaus, nws tuaj yeem pom tias cov yas viscosity ntawm hloov gypsum slurry kuj txo nrog qhov kub thiab txias. Txawm li cas los xij, cov txiaj ntsig kev ntxhov siab thiab cov yas viscosity ntawm ntshiab gypsum slurry nce me ntsis nrog qhov nce ntawm qhov kub thiab txias, uas qhia tau hais tias qhov kev hloov ntawm rheological tsis ntawm HPMC hloov gypsum slurry nyob rau hauv tus txheej txheem ntawm kub nce yog tshwm sim los ntawm kev hloov ntawm HPMC zog.

Cov txiaj ntsig kev ntxhov siab ntawm gypsum slurry qhia txog qhov siab tshaj plaws shear stress tus nqi thaum lub slurry resists shear deformation. Qhov ntau dua cov txiaj ntsig kev ntxhov siab, qhov ruaj khov ntawm gypsum slurry tuaj yeem ua tau. Cov yas viscosity qhia txog qhov deformation ntawm gypsum slurry. Qhov loj dua cov yas viscosity yog, ntev lub sij hawm shear deformation ntawm slurry yuav. Hauv kev xaus, ob qhov rheological tsis ntawm HPMC hloov gypsum slurry txo kom pom tseeb nrog qhov nce ntawm qhov kub thiab txias, thiab cov nyhuv thickening ntawm HPMC ntawm gypsum slurry yog qaug zog.

Lub shear deformation ntawm slurry yog hais txog lub shear thickening los yog shear thinning nyhuv tshwm sim los ntawm slurry thaum raug shear quab yuam. Cov nyhuv shear deformation ntawm slurry tuaj yeem txiav txim los ntawm pseudoplastic index n tau los ntawm qhov nkhaus haum. Thaum n <1, gypsum slurry qhia shear thinning, thiab shear thinning degree ntawm gypsum slurry ua siab dua nrog txo n. Thaum n> 1, gypsum slurry pom shear thickening, thiab shear thickening degree ntawm gypsum slurry nce nrog nce ntawm n. Rheological curves ntawm HPMC hloov gypsum slurry ntawm qhov sib txawv kub raws li Herschel⁃Bulkley (H⁃B) qauv haum, yog li tau txais cov pseudoplastic Performance index n ntawm HPMC hloov gypsum slurry.

Raws li pseudoplastic Performance index n ntawm HPMC hloov gypsum slurry, lub shear deformation ntawm gypsum slurry tov nrog HPMC yog shear thinning, thiab tus nqi n maj mam nce nrog qhov kub thiab txias, uas qhia tau hais tias lub shear thinning cwj pwm ntawm HPMC hloov gypsum yuav. yuav qaug zog rau ib qho twg thaum cuam tshuam los ntawm qhov kub thiab txias.

Raws li qhov pom tseeb viscosity hloov pauv ntawm kev hloov kho gypsum slurry nrog shear tus nqi xam los ntawm cov ntaub ntawv kev ntxhov siab ntawm 75000 mPa · HPMC ntawm qhov kub sib txawv, nws tuaj yeem pom tias cov yas viscosity ntawm cov hloov gypsum slurry txo qis nrog kev nce ntawm shear tus nqi, uas txheeb xyuas qhov tshwm sim haum ntawm H⁃B qauv. Hloov kho gypsum slurry pom shear thinning yam ntxwv. Nrog rau qhov nce ntawm qhov kub thiab txias, qhov pom tseeb viscosity ntawm qhov sib tov txo qis rau qee qhov ntawm qhov qis qis, uas qhia tau hais tias cov nyhuv shear thinning ntawm hloov kho gypsum slurry tsis muaj zog.

Hauv kev siv tiag tiag ntawm gypsum putty, gypsum slurry yuav tsum tau yooj yim rau deform nyob rau hauv cov txheej txheem rubbing thiab kom ruaj khov ntawm so, uas yuav tsum tau gypsum slurry kom muaj cov yam ntxwv zoo shear thinning, thiab kev hloov shear ntawm HPMC hloov gypsum yog tsis tshua muaj. ib qho twg, uas tsis tsim nyog rau kev tsim kho cov ntaub ntawv gypsum. Lub viscosity ntawm HPMC yog ib qho tseem ceeb tsis tau, thiab tseem yog vim li cas nws plays lub luag hauj lwm ntawm thickening los txhim kho cov yam ntxwv sib txawv ntawm kev sib tov ntws. Cellulose ether nws tus kheej muaj cov khoom ntawm cov gel kub, qhov viscosity ntawm nws cov kua aqueous txo qis thaum qhov kub nce, thiab cov gel dawb precipitates thaum mus txog qhov kub thiab txias. Kev hloov ntawm rheological tsis ntawm cellulose ether hloov gypsum nrog kub yog ze ze rau qhov kev hloov ntawm viscosity, vim hais tias cov thickening nyhuv yog tshwm sim los ntawm superposition ntawm cellulose ether thiab tov slurry. Hauv kev tsim qauv tsim qauv, qhov cuam tshuam ntawm ib puag ncig kub ntawm HPMC kev ua haujlwm yuav tsum raug txiav txim siab. Piv txwv li, qhov kub ntawm cov khoom siv raw yuav tsum tau tswj kom kub kub hauv lub caij ntuj sov kom tsis txhob muaj kev ua haujlwm tsis zoo ntawm kev hloov gypsum los ntawm qhov kub thiab txias.

2.2 Kev tuav dej ntawmHPMC hloov kho gypsum

Cov dej tuav ntawm gypsum slurry hloov nrog peb qhov sib txawv ntawm cov cellulose ether yog hloov nrog cov koob tshuaj nkhaus. Nrog rau qhov nce ntawm HPMC ntau npaum li cas, cov dej tuav tus nqi ntawm gypsum slurry yog qhov ua tau zoo dua qub, thiab qhov kev nce ntxiv yuav ruaj khov thaum HPMC ntau npaum li 0.3%. Thaum kawg, cov dej tuav tus nqi ntawm gypsum slurry yog ruaj khov ntawm 90% ~ 95%. Qhov no qhia tau hais tias HPMC muaj qhov pom tseeb ntawm cov dej khaws cia ntawm cov pob zeb muab tshuaj txhuam, tab sis cov dej tuav tsis tau zoo dua vim tias qhov ntau npaum li cas ntxiv. Peb qhov tshwj xeeb ntawm HPMC dej tuav tus nqi sib txawv tsis loj, piv txwv li, thaum cov ntsiab lus yog 0.3%, dej tuav tus nqi yog 5%, tus qauv sib txawv yog 2.2. HPMC nrog cov viscosity siab tshaj plaws tsis yog qhov siab tshaj dej tuav tus nqi, thiab HPMC nrog cov viscosity qis tshaj plaws tsis yog qhov qis tshaj dej tuav. Txawm li cas los xij, piv nrog cov ntshiab gypsum, cov dej tuav tus nqi ntawm peb HPMC rau gypsum slurry yog qhov zoo dua, thiab cov dej tuav tus nqi ntawm cov hloov gypsum hauv 0.3% cov ntsiab lus yog nce 95%, 106%, 97% piv nrog pawg tswj dawb paug. Cellulose ether tuaj yeem pom tseeb txhim kho cov dej tuav ntawm gypsum slurry. Nrog rau qhov nce ntawm HPMC cov ntsiab lus, cov dej tuav tus nqi ntawm HPMC hloov gypsum slurry nrog txawv viscosity maj mus txog qhov saturation point. 10000mPa·sHPMC mus txog qhov saturation point ntawm 0.3%, 75000mPa·s thiab 20000mPa·s HPMC mus txog qhov saturation point ntawm 0.2%. Cov txiaj ntsig tau pom tias cov dej tuav ntawm 75000mPa·s HPMC hloov kho gypsum hloov nrog qhov kub thiab txias nyob rau hauv ntau npaum li cas. Nrog rau qhov txo qis ntawm qhov kub thiab txias, cov dej tuav tus nqi ntawm HPMC hloov gypsum maj mam txo, thaum cov dej tuav tus nqi ntawm cov ntshiab gypsum yeej tseem tsis hloov, qhia tias qhov nce ntawm qhov kub tsis muaj zog ua rau cov dej tuav ntawm HPMC ntawm gypsum. Cov dej tuav tus nqi ntawm HPMC txo los ntawm 31.5% thaum qhov kub thiab txias nce ntawm 20 ℃ mus rau 40 ℃. Thaum qhov kub nce ntawm 40 ℃ mus rau 60 ℃, cov dej tuav tus nqi ntawm HPMC hloov gypsum yog qhov pib zoo ib yam li cov gypsum ntshiab, qhia tias HPMC tau poob cov txiaj ntsig ntawm kev txhim kho cov dej tuav ntawm gypsum lub sijhawm no. Jian Jian thiab Wang Peiming tau hais tias cellulose ether nws tus kheej muaj qhov tshwm sim ntawm thermal gel, qhov kub thiab txias hloov yuav ua rau muaj kev hloov pauv hauv cov viscosity, morphology thiab adsorption ntawm cellulose ether, uas yog khi ua rau kev hloov pauv hauv kev ua haujlwm ntawm slurry mix. Bulichen kuj pom tias qhov viscosity dynamic ntawm cov cement tov uas muaj HPMC poob nrog qhov kub thiab txias.

Kev hloov ntawm cov dej tuav ntawm qhov sib tov tshwm sim los ntawm qhov kub thiab txias yuav tsum tau ua ke nrog cov txheej txheem ntawm cellulose ether. Bulichen piav qhia txog cov txheej txheem uas cellulose ether tuaj yeem khaws dej hauv cov cement. Hauv cov tshuab cement-based, HPMC txhim kho cov dej tuav tus nqi ntawm slurry los ntawm kev txo cov permeability ntawm "filter ncuav mog qab zib" tsim los ntawm cov cementing system. Ib qho tshwj xeeb ntawm HPMC hauv cov kua theem yuav tsim ntau pua nanometers mus rau ob peb microns ntawm colloidal koom haum, qhov no muaj qee qhov ntim ntawm cov qauv polymer tuaj yeem ntsaws cov dej xa mus rau hauv kev sib tov, txo cov permeability ntawm "filter ncuav mog qab zib", kom ua tiav cov dej tuav tau zoo. Bulichen kuj tau qhia tias HPMCS hauv gypsum nthuav tawm tib lub tshuab. Yog li ntawd, txoj kev kawm ntawm hydromechanical txoj kab uas hla ntawm lub koom haum tsim los ntawm HPMC nyob rau hauv cov kua theem yuav piav qhia txog cov nyhuv ntawm HPMC rau cov dej tuav ntawm gypsum.

2.3 Hydrodynamic txoj kab uas hla ntawm HPMC colloid koom haum

Particle faib nkhaus ntawm qhov sib txawv ntawm 75000mPa·s HPMC nyob rau hauv cov kua theem, thiab particle faib nkhaus ntawm peb specifications ntawm HPMC nyob rau hauv cov kua theem ntawm cov concentration ntawm 0.6%. Nws tuaj yeem pom los ntawm qhov particle faib nkhaus ntawm HPMC ntawm peb qhov tshwj xeeb hauv cov kua theem thaum cov concentration yog 0.6%, uas, nrog rau qhov nce ntawm HPMC concentration, qhov loj me me ntawm cov khoom sib txuas tsim nyob rau hauv cov kua theem kuj nce. Thaum cov concentration tsawg, cov khoom uas tsim los ntawm HPMC aggregation yog me me, thiab tsuas yog ib feem me me ntawm HPMC aggregate rau hauv hais txog 100nm. Thaum HPMC concentration yog 1%, muaj coob tus colloidal koom haum nrog ib tug hydrodynamic txoj kab uas hla ntawm txog 300nm, uas yog ib qho tseem ceeb kos npe rau ntawm molecular sib tshooj. Qhov "loj ntim" polymerization qauv tuaj yeem thaiv cov dej xa mus rau hauv qhov sib tov, txo qhov "permeability ntawm ncuav mog qab zib", thiab cov dej tuav ntawm gypsum sib xyaw ntawm qhov concentration no kuj tseem ntau dua 90%. Lub hydromechanical diameters ntawm HPMC nrog sib txawv viscosities nyob rau hauv cov kua theem yog yeej ib yam, uas piav txog qhov zoo sib xws dej tuav tus nqi ntawm HPMC hloov gypsum slurry nrog txawv viscosities.

Particle loj faib nkhaus ntawm 75000mPa·s HPMC nrog 1% concentration ntawm qhov kub thiab txias. Nrog rau qhov kub thiab txias, qhov decomposition ntawm HPMC colloidal koom haum tuaj yeem pom tseeb. Ntawm 40 ℃, qhov loj ntim ntawm 300nm koom haum tag nrho ploj thiab decomposed rau hauv me me ntim hais txog 15nm. Nrog rau qhov nce ntxiv ntawm qhov kub thiab txias, HPMC dhau los ua cov khoom me me, thiab cov dej tuav ntawm gypsum slurry yog ploj tag.

Qhov tshwm sim ntawm HPMC cov khoom hloov pauv nrog qhov nce ntawm qhov kub thiab txias kuj tseem hu ua cov khoom kub gel, qhov kev pom zoo uas twb muaj lawm yog tias ntawm qhov kub thiab txias, HPMC macromolecules thawj zaug tawg hauv dej kom yaj cov tshuaj, HPMC molecules nyob rau hauv siab concentration yuav tsim loj particles koom haum. . Thaum qhov kub thiab txias nce, cov dej ntawm HPMC tsis muaj zog, cov dej ntawm cov saw hlau maj mam tawm, cov koom haum loj sib txuas tau maj mam tawg mus rau hauv cov khoom me me, cov viscosity ntawm cov tshuaj txo, thiab cov qauv peb-seem network yog tsim thaum lub gelation. kub yog mus txog, thiab cov dawb gel yog precipitated.

Bodvik pom tias microstructure thiab adsorption zog ntawm HPMC hauv cov kua theem tau hloov. Ua ke nrog Bulichen txoj kev xav ntawm HPMC colloidal koom haum thaiv slurry dej thauj channel, nws tau txiav txim siab tias qhov nce ntawm qhov kub thiab txias tau ua rau kev sib cais ntawm HPMC colloidal koom haum, uas ua rau txo cov dej tuav ntawm hloov gypsum.

3. Cov lus xaus

(1) Cellulose ether nws tus kheej muaj viscosity siab thiab "superimposed" nyhuv nrog gypsum slurry, ua si ib qho pom tseeb thickening nyhuv. Nyob rau hauv chav tsev kub, cov nyhuv thickening yuav pom tseeb dua nrog qhov nce ntawm viscosity thiab ntau npaum ntawm cellulose ether. Txawm li cas los xij, nrog qhov nce ntawm qhov kub thiab txias, qhov viscosity ntawm cellulose ether txo qis, nws cov nyhuv thickening tsis muaj zog, cov yield shear kev nyuaj siab thiab yas viscosity ntawm gypsum mix txo, pseudoplasticity tsis muaj zog, thiab cov cuab yeej tsim kho yuav phem dua.

(2) Cellulose ether txhim kho cov dej tuav ntawm gypsum, tab sis nrog kev nce ntawm qhov kub thiab txias, cov dej khaws cia ntawm kev hloov gypsum kuj txo qis, txawm tias nyob rau ntawm 60 ℃ yuav tag nrho cov nyhuv ntawm cov dej tuav. Cov dej tuav tus nqi ntawm gypsum slurry tau zoo dua los ntawm cellulose ether, thiab cov dej tuav tus nqi ntawm HPMC hloov kho gypsum slurry nrog cov viscosity sib txawv maj mam mus txog qhov chaw saturation nrog qhov nce ntawm ntau npaum. Gypsum dej tuav yog feem ntau proportional rau lub viscosity ntawm cellulose ether, nyob rau hauv siab viscosity muaj me ntsis cuam tshuam.

(3) Cov yam ntxwv sab hauv uas hloov cov dej tuav ntawm cellulose ether nrog qhov kub thiab txias yog ze ze rau lub microscopic morphology ntawm cellulose ether hauv cov kua theem. Ntawm qee qhov concentration, cellulose ether nyiam sib sau ua ke los tsim cov koom haum colloidal loj, thaiv cov dej thauj channel ntawm gypsum sib tov kom ua tiav cov dej tuav. Txawm li cas los xij, nrog qhov nce ntawm qhov kub thiab txias, vim yog cov khoom siv thermal gelation ntawm cellulose ether nws tus kheej, yav tas los tsim cov colloid koom haum loj redisperses, ua rau poob ntawm dej tuav kev ua haujlwm.