Cellulose ethers hauv pobzeb nplaum

1 Kev Taw Qhia

Cement-raws li pobzeb nplaum yog tam sim no qhov loj tshaj plaws ntawm daim ntawv thov tshwj xeeb qhuav-sib xyaw mortar, uas yog tsim los ntawm cov cement raws li cov khoom siv cementitious thiab ntxiv los ntawm cov khoom sib xyaw ua ke, cov dej tuav cov neeg ua haujlwm, cov neeg ua haujlwm thaum ntxov, cov hmoov latex thiab lwm yam organic lossis inorganic additives. sib tov.Feem ntau, nws tsuas yog yuav tsum tau tov nrog dej thaum siv.Piv nrog rau cov cement mortar zoo tib yam, nws tuaj yeem txhim kho lub zog sib txuas ntawm cov khoom siv thiab cov substrate, thiab muaj kev ua haujlwm zoo thiab cov dej zoo thiab dej tsis kam.Nws yog tsuas yog siv los paste cov ntaub ntawv zoo nkauj xws li lub tsev sab hauv thiab sab nrauv phab ntsa vuas, pem teb vuas, thiab lwm yam. Nws yog dav siv nyob rau hauv sab hauv thiab sab nrauv phab ntsa, pem teb, chav dej, chav ua noj thiab lwm qhov chaw kho kom zoo nkauj lub tsev.Nws yog tam sim no feem ntau siv pobzeb sib txuas cov ntaub ntawv.

Feem ntau thaum peb txiav txim qhov kev ua tau zoo ntawm cov pobzeb nplaum, peb tsis tsuas yog them sai sai rau nws txoj haujlwm ua haujlwm thiab muaj peev xwm tiv thaiv zawv zawg, tab sis kuj xyuam xim rau nws lub zog txhua yam thiab lub sijhawm qhib.Cellulose ether nyob rau hauv pobzeb nplaum tsis tsuas yog cuam tshuam rau cov khoom siv rheological ntawm porcelain nplaum, xws li kev ua haujlwm du, nplaum riam, thiab lwm yam.

2. Qhov cuam tshuam rau lub sijhawm qhib ntawm pobzeb nplaum

Thaum cov hmoov roj hmab thiab cellulose ether sib koom ua ke hauv cov khib nyiab ntub dej, qee cov ntaub ntawv qauv qhia tau hais tias cov hmoov roj hmab muaj zog kinetic zog los txuas rau cov khoom siv cement hydration, thiab cellulose ether muaj ntau nyob rau hauv cov kua dej interstitial, uas cuam tshuam ntau dua Mortar viscosity thiab teem sij hawm.Qhov nro ntawm cellulose ether yog siab dua li ntawm cov hmoov roj hmab, thiab ntau dua cellulose ether enrichment ntawm mortar interface yuav muaj txiaj ntsig zoo rau kev tsim cov hydrogen bonds ntawm lub hauv paus nto thiab cellulose ether.

Nyob rau hauv lub mortar ntub dej, cov dej nyob rau hauv lub mortar evaporates, thiab cellulose ether yog enriched rau ntawm qhov chaw, thiab ib tug zaj duab xis yuav tsim nyob rau ntawm qhov chaw ntawm lub mortar nyob rau hauv 5 feeb, uas yuav txo tau cov tom ntej no evaporation tus nqi, raws li cov dej ntau dua. tshem tawm ntawm cov mortar thicker Ib feem ntawm nws migrates mus rau lub thinner mortar txheej, thiab cov zaj duab xis tsim nyob rau hauv thaum pib yog ib nrab yaj, thiab cov migration ntawm dej yuav coj ntau cellulose ether enrichment nyob rau hauv mortar nto.

Yog li ntawd, zaj duab xis tsim ntawm cellulose ether nyob rau saum npoo ntawm mortar muaj kev cuam tshuam zoo rau kev ua haujlwm ntawm mortar.1) Cov zaj duab xis tsim yog nyias dhau thiab yuav yaj ob zaug, uas tsis tuaj yeem txwv cov evaporation ntawm dej thiab txo lub zog.2) Cov zaj duab xis tsim yog tuab heev, qhov concentration ntawm cellulose ether nyob rau hauv lub mortar interstitial kua yog siab, thiab viscosity siab, yog li nws tsis yooj yim rau tawg zaj duab xis nto thaum cov vuas yog pasted.Nws tuaj yeem pom tias cov yeeb yaj kiab tsim cov khoom ntawm cellulose ether muaj kev cuam tshuam ntau dua rau lub sijhawm qhib.Hom cellulose ether (HPMC, HEMC, MC, thiab lwm yam) thiab cov degree ntawm etherification (substitution degree) ncaj qha cuam tshuam rau cov yeeb yaj kiab-tsim cov khoom ntawm cellulose ether, thiab hardness thiab toughness ntawm zaj duab xis.

3. Lub zog ntawm kev kos duab

Ntxiv nrog rau kev muab cov khoom siv tau hais los saum toj no rau cov tshuaj khib nyiab, cellulose ether kuj tseem ncua cov dej kinetics ntawm cov cement.Cov nyhuv retarding no feem ntau yog vim qhov adsorption ntawm cellulose ether molecules ntawm ntau theem ntxhia hauv cov cement system tau hydrated, tab sis feem ntau hais lus, qhov kev pom zoo yog tias cellulose ether molecules feem ntau adsorbed ntawm dej xws li CSH thiab calcium hydroxide.Ntawm cov khoom siv tshuaj, nws tsis tshua muaj adsorbed ntawm thawj theem ntxhia ntawm clinker.Tsis tas li ntawd, cellulose ether txo qhov kev txav mus los ntawm ions (Ca2+, SO42-, ...) hauv cov pore tov vim qhov nce viscosity ntawm pore tov, yog li ncua ntxiv cov txheej txheem hydration.

Viscosity yog lwm qhov tseem ceeb, uas sawv cev rau cov yam ntxwv ntawm cov cellulose ether.Raws li tau hais los saum toj no, cov viscosity feem ntau cuam tshuam rau cov dej khaws cia thiab tseem muaj txiaj ntsig zoo rau kev ua haujlwm ntawm cov mortar tshiab.Txawm li cas los xij, cov kev tshawb fawb sim tau pom tias cov viscosity ntawm cellulose ether yuav luag tsis cuam tshuam rau cov cement hydration kinetics.Qhov hnyav ntawm molecular muaj me ntsis cuam tshuam rau hydration, thiab qhov sib txawv siab tshaj plaws ntawm qhov sib txawv molecular hnyav tsuas yog 10min.Yog li ntawd, molecular hnyav tsis yog ib qho tseem ceeb parameter los tswj cov cement hydration.

Qhov retardation ntawm cellulose ether nyob ntawm nws cov qauv tshuaj, thiab cov qauv dav dav tau xaus lus tias, rau MHEC, qhov siab dua ntawm cov tshuaj methylation, qhov cuam tshuam tsawg dua ntawm cellulose ether.Tsis tas li ntawd, cov nyhuv retarding ntawm hydrophilic hloov pauv (xws li hloov mus rau HEC) muaj zog dua li kev hloov pauv hydrophobic (xws li hloov mus rau MH, MHEC, MHPC).Cov nyhuv retarding ntawm cellulose ether feem ntau cuam tshuam los ntawm ob qhov tsis muaj, hom thiab ntau ntawm cov pab pawg hloov.

Peb qhov kev sim ua haujlwm tseem pom tau tias cov ntsiab lus ntawm cov neeg hloov pauv ua lub luag haujlwm tseem ceeb hauv lub zog ntawm cov nplais nplaum.Peb tau soj ntsuam qhov kev ua tau zoo ntawm HPMC nrog ntau qib ntawm kev hloov pauv hauv cov nplais nplaum, thiab kuaj cov txiaj ntsig ntawm cellulose ethers uas muaj cov pab pawg sib txawv nyob rau hauv kev kho mob sib txawv ntawm Cov teebmeem ntawm cov khoom siv ntawm cov nplais nplaum.

Hauv kev sim, peb xav txog HPMC, uas yog ib qho ether sib xyaw, yog li peb yuav tsum muab ob daim duab ua ke.Rau HPMC, nws xav tau qee qhov kev nqus dej kom ntseeg tau tias nws cov dej solubility thiab lub teeb xa mus.Peb paub cov ntsiab lus ntawm kev hloov pauv Nws kuj txiav txim siab qhov kub thiab txias ntawm HPMC, uas kuj txiav txim siab txog kev siv ib puag ncig ntawm HPMC.Nyob rau hauv txoj kev no, pawg ntsiab lus ntawm HPMC uas feem ntau siv tau kuj yog nyob rau hauv ntau yam.Nyob rau hauv no ntau yam, yuav ua li cas los ua ke methoxy thiab hydroxypropoxy Nyob rau hauv thiaj li yuav ua tiav cov nyhuv zoo tshaj plaws yog cov ntsiab lus ntawm peb kev tshawb fawb.Daim duab 2 qhia tau hais tias nyob rau hauv ib tug tej yam ntau yam, ib tug nce nyob rau hauv cov ntsiab lus ntawm methoxyl pab pawg neeg yuav ua rau ib tug downward trend nyob rau hauv lub zog rub-tawm, thaum ib tug nce nyob rau hauv cov ntsiab lus ntawm hydroxypropoxyl pawg yuav ua rau ib tug nce nyob rau hauv lub zog rub tawm. .Muaj qhov zoo sib xws rau cov sijhawm qhib.

Cov kev hloov pauv ntawm kev siv tshuab lub zog nyob rau hauv lub sijhawm qhib yog zoo ib yam nrog rau hauv qhov kub thiab txias.HPMC nrog cov ntsiab lus siab methoxyl (DS) thiab cov ntsiab lus tsis tshua muaj hydroxypropoxyl (MS) muaj qhov toughness zoo ntawm zaj duab xis, tab sis nws yuav cuam tshuam rau cov mortar ntub ntawm qhov tsis sib xws.khoom wetting zog.