Cov nyhuv ntawm cellulose ether ntawm cov nplaum nplaum

Cement-raws li pobzeb nplaum yog daim ntawv thov loj tshaj plaws ntawm cov khoom siv tshwj xeeb qhuav sib xyaw tam sim no.Nws yog ib yam ntawm cov organic lossis inorganic admixture nrog cov cement ua cov khoom siv cementing tseem ceeb thiab ntxiv nrog kev sib sau ua ke, dej tuav tus neeg saib xyuas, tus neeg sawv cev thaum ntxov thiab cov hmoov latex.sib tov.Feem ntau, nws tsuas yog yuav tsum tau tov nrog dej.Piv nrog rau cov cement mortar zoo tib yam, nws tuaj yeem txhim kho kev sib raug zoo ntawm cov khoom siv thiab cov substrate, muaj cov cuab yeej zoo los tiv thaiv plam thiab muaj cov dej tsis zoo thiab kub kub.Nws kuj yog siv rau kev kho kom zoo nkauj ntawm sab hauv thiab sab nrauv phab ntsa vuas, pem teb vuas thiab lwm yam khoom siv kho kom zoo nkauj.Nws yog dav siv hauv kev kho kom zoo nkauj ntawm phab ntsa sab hauv thiab sab nrauv, hauv pem teb, chav dej, chav ua noj, thiab lwm yam. Nws yog cov pobzeb siv dav tshaj plaws.Cov khoom sib khi.

Feem ntau, thaum peb txiav txim siab qhov kev ua tau zoo ntawm cov nplais nplaum, peb yuav tsum tau them sai sai rau nws cov khoom siv dag zog thiab lub sijhawm qhib ntxiv rau nws cov kev ua haujlwm thiab kev tiv thaiv kev ua haujlwm.Ntxiv rau qhov cuam tshuam rau cov khoom siv rheological ntawm porcelain roj hmab, xws li smoothness ntawm kev ua haujlwm, qhov xwm txheej ntawm cov nplaum nplaum, thiab lwm yam, cov cellulose ether muaj zog cuam tshuam rau cov khoom siv ntawm cov nplais nplaum.

1. Lub sijhawm qhib
Thaum twgRedispersible polymer hmoovthiabcellulose ethercoexist nyob rau hauv cov mortar ntub, qee cov ntaub ntawv qauv qhia tau hais tias cov roj hmab hmoov muaj zog kinetic zog txuas rau cov cement hydration khoom, thiab cov cellulose ether muaj ntau nyob rau hauv cov kua interstitial, uas cuam tshuam ntau dua.Lub viscosity thiab teem sij hawm ntawm lub mortar.Qhov nro ntawm cov cellulose ether yog loj dua li ntawm cov hmoov roj hmab, thiab kev ua kom muaj ntau ntawm cellulose ether ntawm lub mortar interface yog qhov zoo los tsim cov hydrogen bond ntawm lub hauv paus nto thiab cellulose ether.

Nyob rau hauv lub mortar ntub dej, cov dej nyob rau hauv lub mortar evaporates, cellulose ether yog enriched rau ntawm qhov chaw, thiab ib tug zaj duab xis yog tsim nyob rau hauv lub mortar nyob rau hauv 5 feeb, uas yuav txo tau cov tom ntej evaporation tus nqi, raws li cov dej ntau yog thicker los ntawm lub mortar. mortar.Ib feem ntawm kev tsiv teb tsaws mus rau cov txheej nyias nyias ntawm cov mortar txheej, thawj qhov qhib ntawm daim nyias nyias yog ib feem yaj, thiab kev tsiv teb tsaws ntawm cov dej yuav coj ntau cellulose ether mus rau saum npoo ntawm mortar.

Cov zaj duab xis tsim ntawm cellulose ether nyob rau saum npoo ntawm mortar muaj kev cuam tshuam zoo rau kev ua haujlwm ntawm mortar:
Ua ntej, cov zaj duab xis tsim yog nyias heev, nws yuav yaj ob zaug, tsis tuaj yeem txwv cov evaporation ntawm dej, txo lub zog.
Qhov thib ob, cov zaj duab xis tsim yog tuab heev, qhov concentration ntawm cellulose ether nyob rau hauv lub mortar interstitial kua yog siab, thiab viscosity yog loj.Thaum cov pobzeb yog pasted, nws tsis yooj yim rau tawg zaj duab xis nto.
Los ntawm qhov no, nws tau nkag siab tias zaj duab xis tsim cov khoom ntawm cellulose ether muaj kev cuam tshuam loj rau lub sijhawm qhib.Hom cellulose ether (HPMC,HEMC, MC, thiab lwm yam) thiab qib ntawm etherification (degree ntawm kev hloov pauv) ncaj qha cuam tshuam rau cov yeeb yaj kiab tsim cov khoom ntawm cellulose ether, thiab hardness thiab toughness ntawm zaj duab xis.

2, zog
Ntxiv nrog rau kev muab cov khoom muaj txiaj ntsig ntau yam uas tau piav qhia saum toj no rau hauv mortar, cellulose ether retards hydration kinetics ntawm cov cement.Qhov retardation no feem ntau yog vim qhov adsorption ntawm cellulose ether molecules ntawm ntau yam ntxhia theem hauv hydrated cement system, tab sis feem ntau hais lus, cov cellulose ether molecules feem ntau yog 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, vim qhov nce hauv viscosity ntawm pore tov, cellulose ether txo cov kev txav mus los ntawm ions (Ca2+, SO42-, ...) nyob rau hauv cov pore tov, yog li ntxiv ncua cov txheej txheem hydration.

Viscosity yog lwm qhov tseem ceeb uas sawv cev rau cov tshuaj lom neeg ntawm cellulose ethers.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 hydration kinetics ntawm cement.Qhov hnyav molecular muaj me ntsis cuam tshuam rau hydration, thiab qhov sib txawv loj tshaj ntawm qhov sib txawv molecular hnyav tsuas yog 10 min.Yog li, qhov hnyav molecular tsis yog qhov tseem ceeb rau kev tswj cov cement hydration.
"Daim ntawv thov ntawm Cellulose Ether nyob rau hauv Cement-raws li Qhuav-mixed Mortar Cov Khoom" qhia meej tias kev rov qab ntawm cellulose ether nyob ntawm nws cov qauv tshuaj.Qhov kev sib piv dav dav tau sau tseg yog tias rau MHEC, qhov siab dua ntawm cov tshuaj methylation, qhov me me ntawm cellulose ether retardation.Tsis tas li ntawd, kev hloov pauv hauv hydrophilic (xws li hloov mus rau HEC) muaj kev nruj 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 yam tsis muaj hom thiab tus nqi ntawm cov pab pawg hloov.
Peb qhov kev sim ua haujlwm kuj pom tau tias cov ntsiab lus ntawm cov khoom hloov pauv tau 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 nplaum nplaum, thiab kuaj cov cellulose ether khub nrog ntau pab pawg nyob rau hauv kev kho mob sib txawv.Kev cuam tshuam ntawm cov khoom siv ntawm cov pobzeb nplaum, Daim duab 2 thiab daim duab 3 yog cov teebmeem ntawm kev hloov pauv hauv methoxy (DS) cov ntsiab lus thiab hydroxypropoxy (MS) cov ntsiab lus ntawm lub zog rub-down ntawm cov pobzeb nplaum ntawm chav tsev kub.

Daim duab 2

Daim duab 3

Hauv kev xeem, peb xav txogHydroxypropyl methyl cellulose (HPMC), uas yog ib tug complex ether.Yog li ntawd, peb yuav tsum muab ob daim duab ua ke.Rau HPMC, peb xav tau cov khoom siv los xyuas kom meej cov dej solubility thiab lub teeb xa mus.Peb paub cov ntsiab lus ntawm cov khoom hloov.Nws kuj tseem txiav txim siab txog qhov kub thiab txias ntawm HPMC, uas txiav txim siab qhov chaw nyob hauv HPMC siv.Yog li ntawd, cov ntsiab lus ntawm HPMC feem ntau siv kuj yog framed nyob rau hauv ntau yam.Yuav ua li cas muab methoxy thiab hydroxypropoxy pawg nyob rau hauv no ntau yam Kom ua tau zoo tshaj plaws yog qhov peb kawm.Daim duab 2 qhia tau hais tias nyob rau hauv ib tug tej yam ntau yam, qhov nce ntawm methoxyl cov ntsiab lus yuav ua rau ib tug downward trend ntawm lub zog rub, thaum lub hydroxypropoxyl cov ntsiab lus yuav nce thiab lub zog rub yuav nce.Rau lub sijhawm qhib, muaj cov teebmeem zoo sib xws.