Cellulose ethers hauv cov nplaum pobzeb

1 Kev Taw Qhia

Cov nplaum pobzeb uas ua los ntawm cement yog cov nplaum qhuav uas siv ntau tshaj plaws tam sim no, uas yog ua los ntawm cov cement ua cov khoom siv cement tseem ceeb thiab ntxiv los ntawm cov pob zeb sib xyaw, cov tshuaj uas khaws dej, cov tshuaj uas muaj zog thaum ntxov, hmoov latex thiab lwm yam khoom siv organic lossis inorganic. Feem ntau, nws tsuas yog yuav tsum tau sib xyaw nrog dej thaum siv. Piv nrog cov nplaum cement ib txwm, nws tuaj yeem txhim kho lub zog sib txuas ntawm cov khoom siv ntsej muag thiab cov khoom siv hauv pem teb, thiab muaj kev tiv thaiv kev plam zoo thiab tiv thaiv dej thiab dej zoo heev. Nws feem ntau yog siv los nplaum cov khoom siv kho kom zoo nkauj xws li cov vuas phab ntsa sab hauv thiab sab nraud, cov vuas pem teb, thiab lwm yam. Nws yog siv dav hauv cov phab ntsa sab hauv thiab sab nraud, pem teb, chav dej, chav ua noj thiab lwm qhov chaw kho kom zoo nkauj. Nws yog cov khoom siv sib txuas pobzeb uas siv ntau tshaj plaws tam sim no.

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

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

Thaum cov hmoov roj hmab thiab cellulose ether sib koom ua ke hauv cov mortar ntub, qee cov qauv ntaub ntawv qhia tias cov hmoov roj hmab muaj lub zog kinetic muaj zog dua los txuas rau cov khoom siv cement hydration, thiab cellulose ether muaj ntau dua hauv cov kua dej interstitial, uas cuam tshuam rau ntau Mortar viscosity thiab teeb tsa lub sijhawm. Qhov nro ntawm cellulose ether siab dua li ntawm cov hmoov roj hmab, thiab ntau cellulose ether enrichment ntawm lub mortar interface yuav pab tau rau kev tsim cov hydrogen bonds ntawm lub hauv paus nto thiab cellulose ether.

Hauv cov mortar ntub, cov dej hauv cov mortar yuav qhuav, thiab cov cellulose ether yuav nplua nuj rau ntawm qhov chaw, thiab ib zaj duab xis yuav tsim rau ntawm qhov chaw ntawm cov mortar hauv 5 feeb, uas yuav txo qhov kev nqus dej tom qab, vim tias ntau cov dej raug tshem tawm ntawm cov mortar tuab dua Ib feem ntawm nws yuav tsiv mus rau cov txheej mortar nyias dua, thiab cov zaj duab xis uas tsim thaum pib yuav yaj ib nrab, thiab kev tsiv teb tsaws chaw ntawm dej yuav coj ntau cov cellulose ether nplua nuj rau ntawm qhov chaw mortar.

Yog li ntawd, zaj duab xis tsim ntawm cellulose ether ntawm qhov chaw ntawm cov mortar muaj kev cuam tshuam loj rau kev ua haujlwm ntawm cov mortar. 1) Zaj duab xis tsim yog nyias dhau thiab yuav yaj ob zaug, uas tsis tuaj yeem txwv tsis pub cov dej evaporation thiab txo qhov muaj zog. 2) Zaj duab xis tsim yog tuab dhau, qhov concentration ntawm cellulose ether hauv cov kua interstitial mortar yog siab, thiab viscosity yog siab, yog li nws tsis yooj yim rau kev tawg zaj duab xis saum npoo thaum cov vuas raug nplaum. Nws tuaj yeem pom tias cov khoom tsim zaj duab xis ntawm cellulose ether muaj kev cuam tshuam ntau dua rau lub sijhawm qhib. Hom cellulose ether (HPMC, HEMC, MC, thiab lwm yam) thiab qib ntawm etherification (hloov chaw degree) ncaj qha cuam tshuam rau cov khoom tsim zaj duab xis ntawm cellulose ether, thiab qhov nyuaj thiab toughness ntawm zaj duab xis.

3. Qhov cuam tshuam rau lub zog kos duab

Ntxiv rau qhov muab cov khoom zoo li no rau cov mortar, cellulose ether kuj tseem ncua qhov hydration kinetics ntawm cement. Qhov cuam tshuam no feem ntau yog vim qhov adsorption ntawm cellulose ether molecules ntawm ntau yam minerals theem hauv lub cement system raug hydrated, tab sis feem ntau hais lus, qhov kev pom zoo yog tias cellulose ether molecules feem ntau yog adsorbed ntawm dej xws li CSH thiab calcium hydroxide. Ntawm cov khoom tshuaj, nws tsis tshua muaj adsorbed ntawm thawj mineral theem ntawm clinker. Tsis tas li ntawd, cellulose ether txo qhov kev txav mus los ntawm cov ions (Ca2 +, SO42-, ...) hauv cov kua pore vim yog qhov nce viscosity ntawm cov kua pore, yog li ntawd ncua ntxiv cov txheej txheem hydration.

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

Qhov kev ncua ntawm cellulose ether nyob ntawm nws cov qauv tshuaj lom neeg, thiab qhov sib txawv dav dav xaus lus tias, rau MHEC, qhov siab dua ntawm methylation, qhov cuam tshuam tsawg dua ntawm cellulose ether. Tsis tas li ntawd, qhov cuam tshuam ntawm hydrophilic hloov chaw (xws li hloov chaw rau HEC) muaj zog dua li ntawm hydrophobic hloov chaw (xws li hloov chaw rau MH, MHEC, MHPC). Qhov cuam tshuam ntawm cellulose ether feem ntau cuam tshuam los ntawm ob qho kev ntsuas, hom thiab qhov ntau ntawm cov pab pawg hloov chaw.

Peb cov kev sim ua haujlwm kuj pom tias cov ntsiab lus ntawm cov khoom hloov pauv ua lub luag haujlwm tseem ceeb hauv lub zog kho tshuab ntawm cov nplais pobzeb. Peb tau soj ntsuam qhov kev ua tau zoo ntawm HPMC nrog ntau qib sib txawv ntawm kev hloov pauv hauv cov nplais pobzeb, thiab sim cov nyhuv ntawm cellulose ethers uas muaj ntau pawg sib txawv nyob rau hauv cov xwm txheej kho sib txawv ntawm Cov nyhuv rau cov khoom siv kho tshuab ntawm cov nplais pobzeb.

Hauv kev sim, peb xav txog HPMC, uas yog cov ether sib xyaw, yog li peb yuav tsum muab ob daim duab tso ua ke. Rau HPMC, nws xav tau qee qib ntawm kev nqus kom ntseeg tau tias nws cov dej yaj thiab lub teeb xa mus. Peb paub cov ntsiab lus ntawm cov khoom hloov pauv Nws kuj txiav txim siab qhov kub ntawm HPMC, uas kuj txiav txim siab qhov chaw siv ntawm HPMC. Ua li no, cov ntsiab lus pab pawg ntawm HPMC uas feem ntau siv tau kuj tau teeb tsa hauv ib qho ntau. Hauv qhov ntau no, yuav ua li cas los sib xyaw methoxy thiab hydroxypropoxy Txhawm rau kom ua tiav qhov zoo tshaj plaws yog cov ntsiab lus ntawm peb txoj kev tshawb fawb. Daim duab 2 qhia tau hais tias hauv ib qho ntau, kev nce ntxiv ntawm cov ntsiab lus ntawm methoxyl pawg yuav ua rau muaj kev poob qis hauv lub zog rub tawm, thaum kev nce ntxiv ntawm cov ntsiab lus ntawm hydroxypropoxyl pawg yuav ua rau muaj kev nce ntxiv ntawm lub zog rub tawm. Muaj cov txiaj ntsig zoo sib xws rau lub sijhawm qhib.

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