Cellulose ether ntawm Cement-raws li 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-forming zog 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 cov kev txav mus los ntawm ions (Ca2+, SO42-, ...) hauv cov pore tov vim qhov nce hauv cov viscosity ntawm cov pore tov, yog li ntxiv ncua 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.

"Daim ntawv thov ntawm Cellulose Ether hauv Cement-Based Dry-Mixed Mortar Products" tau taw qhia meej tias kev rov qab ntawm cellulose ether nyob ntawm nws cov qauv tshuaj.Thiab cov qauv dav dav xaus lus yog tias rau MHEC, qhov siab dua ntawm cov tshuaj methylation, qhov me dua cov nyhuv retarding 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).

Hauv kev sim, peb xav txog HPMC, uas yog ib qho kev sib xyaw ether.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 tias cov ntsiab lus ntawm cov neeg hloov pauv kuj txiav txim siab qhov kub thiab txias ntawm HPMC, uas yog, Nws txiav txim siab siv ib puag ncig ntawm HPMC, yog li cov pab pawg cov 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 kom ua tiav cov txiaj ntsig zoo tshaj plaws yog cov ntsiab lus ntawm peb cov kev tshawb fawb.Nyob rau hauv ib tug tej yam ntau yam, ib tug nce nyob rau hauv cov ntsiab lus ntawm methoxyl pawg yuav ua rau ib tug downward trend nyob rau hauv lub rub-tawm lub zog, 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 cov neeg kho tshuab lub zog nyob rau hauv lub sijhawm qhib yog ua raws li qhov ntsuas kub ib txwm muaj, uas kuj zoo ib yam nrog lub zog ntawm cov cellulose ether zaj duab xis peb tau tham txog hauv Tshooj 2. Cov ntsiab lus ntawm methoxyl (DS) yog siab thiab cov hydroxypropoxyl. HPMC nrog cov ntsiab lus qis (MS) muaj qhov ua tau zoo ntawm cov yeeb yaj kiab, tab sis nws yuav cuam tshuam rau qhov ntub dej ntawm cov mortar ntub rau cov khoom siv saum npoo av.