Hauv cov mortar sib xyaw ua tiav, qhov ntxiv ntawm cellulose ether yog tsawg heev, tab sis nws tuaj yeem txhim kho qhov ua tau zoo ntawm cov mortar ntub, thiab nws yog ib qho khoom ntxiv tseem ceeb uas cuam tshuam rau kev ua tau zoo ntawm mortar. Kev xaiv cov cellulose ethers ntawm ntau yam sib txawv, viscosities sib txawv, qhov loj me ntawm cov khoom sib txawv, qib sib txawv ntawm viscosity thiab cov nqi ntxiv yuav muaj qhov cuam tshuam zoo rau kev txhim kho qhov ua tau zoo ntawm cov hmoov qhuav mortar. Tam sim no, ntau lub masonry thiab plastering mortars muaj kev ua tau zoo tsis zoo, thiab cov dej slurry yuav sib cais tom qab ob peb feeb ntawm sawv. Kev khaws dej yog ib qho kev ua tau zoo tseem ceeb ntawm methyl cellulose ether, thiab nws kuj yog ib qho kev ua tau zoo uas ntau lub tuam txhab tsim cov mortar qhuav hauv tsev, tshwj xeeb tshaj yog cov neeg nyob rau sab qab teb uas muaj qhov kub siab, them sai sai rau. Cov yam ntxwv cuam tshuam rau qhov khaws dej ntawm cov mortar qhuav sib xyaw suav nrog qhov ntau ntawm MC ntxiv, viscosity ntawm MC, qhov zoo ntawm cov khoom me me thiab qhov kub ntawm qhov chaw siv.
1. Lub Tswv Yim
Cellulose ether yog ib qho polymer hluavtaws ua los ntawm cov cellulose ntuj los ntawm kev hloov kho tshuaj. Cellulose ether yog ib qho derivative ntawm cellulose ntuj. Kev tsim cov cellulose ether txawv ntawm cov polymers hluavtaws. Nws cov khoom siv yooj yim tshaj plaws yog cellulose, ib qho tshuaj polymer ntuj. Vim yog qhov tshwj xeeb ntawm cov qauv cellulose ntuj, cellulose nws tus kheej tsis muaj peev xwm los cuam tshuam nrog cov neeg sawv cev etherification. Txawm li cas los xij, tom qab kev kho mob ntawm tus neeg sawv cev o, cov hydrogen bonds muaj zog ntawm cov saw hlau molecular thiab cov saw hlau raug rhuav tshem, thiab kev tso tawm ntawm pawg hydroxyl ua rau cov alkali cellulose reactive. Tau txais cellulose ether.
Cov khoom ntawm cellulose ethers nyob ntawm hom, tus lej thiab kev faib tawm ntawm cov substituents. Kev faib tawm ntawm cellulose ethers kuj yog raws li hom substituents, qib ntawm etherification, solubility thiab cov khoom siv cuam tshuam. Raws li hom substituents ntawm cov saw molecular, nws tuaj yeem faib ua monoether thiab sib xyaw ether. MC peb feem ntau siv yog monoether, thiab HPMC yog sib xyaw ether. Methyl cellulose ether MC yog cov khoom tom qab hydroxyl pawg ntawm chav glucose ntawm cellulose ntuj yog hloov los ntawm methoxy. Nws yog cov khoom tau los ntawm kev hloov ib feem ntawm hydroxyl pawg ntawm chav nrog ib pawg methoxy thiab lwm qhov nrog hydroxypropyl pawg. Cov qauv qauv yog [C6H7O2 (OH) 3-mn (OCH3) m [OCH2CH (OH) CH3] n] x Hydroxyethyl methyl cellulose ether HEMC, cov no yog cov ntau yam tseem ceeb siv dav thiab muag hauv khw.
Hais txog kev yaj, nws muaj peev xwm muab faib ua ionic thiab non-ionic. Cov dej-soluble non-ionic cellulose ethers feem ntau yog tsim los ntawm ob series ntawm alkyl ethers thiab hydroxyalkyl ethers. Ionic CMC feem ntau yog siv rau hauv cov tshuaj ntxuav hluavtaws, textile printing thiab dyeing, zaub mov thiab roj tshawb nrhiav. Non-ionic MC, HPMC, HEMC, thiab lwm yam feem ntau yog siv rau hauv cov ntaub ntawv siv hauv tsev, latex coatings, tshuaj, tshuaj txhua hnub, thiab lwm yam. Siv ua thickener, dej khaws cia tus neeg sawv cev, stabilizer, dispersant thiab zaj duab xis tsim tus neeg sawv cev.
Qhov thib ob, qhov dej khaws cia ntawm cellulose ether
Kev khaws dej ntawm cellulose ether: Hauv kev tsim cov ntaub ntawv tsim kho, tshwj xeeb tshaj yog cov hmoov qhuav mortar, cellulose ether ua lub luag haujlwm tsis tuaj yeem hloov pauv, tshwj xeeb tshaj yog hauv kev tsim cov mortar tshwj xeeb (hloov kho mortar), nws yog ib qho tseem ceeb thiab tseem ceeb.
Lub luag haujlwm tseem ceeb ntawm cov cellulose ether uas yaj tau hauv dej hauv cov mortar feem ntau muaj peb yam, ib qho yog lub peev xwm khaws dej zoo heev, qhov thib ob yog qhov cuam tshuam rau qhov sib xws thiab thixotropy ntawm mortar, thiab qhov thib peb yog kev sib cuam tshuam nrog cement. Cov nyhuv khaws dej ntawm cellulose ether nyob ntawm qhov nqus dej ntawm cov txheej hauv paus, cov khoom sib xyaw ntawm cov mortar, qhov tuab ntawm cov txheej mortar, qhov xav tau dej ntawm cov mortar, thiab lub sijhawm teeb tsa ntawm cov khoom teeb tsa. Kev khaws dej ntawm cellulose ether nws tus kheej los ntawm qhov solubility thiab dehydration ntawm cellulose ether nws tus kheej. Raws li peb txhua tus paub, txawm hais tias cov saw hlau molecular cellulose muaj ntau tus lej ntawm cov pab pawg OH uas muaj dej ntau, nws tsis yaj hauv dej, vim tias cov qauv cellulose muaj qib siab ntawm crystallinity.
Lub peev xwm hydration ntawm hydroxyl pawg ib leeg tsis txaus los npog cov hydrogen bonds muaj zog thiab van der Waals forces ntawm cov molecules. Yog li ntawd, nws tsuas yog o tab sis tsis yaj hauv dej. Thaum ib qho substituent raug qhia rau hauv cov saw molecular, tsis yog tsuas yog cov substituent rhuav tshem cov saw hydrogen, tab sis kuj tseem muaj cov interchain hydrogen bond raug rhuav tshem vim yog qhov wedging ntawm cov substituent ntawm cov saw sib ze. Qhov loj dua cov substituent, qhov ntau dua qhov deb ntawm cov molecules. Qhov ntau dua qhov deb. Qhov ntau dua qhov cuam tshuam ntawm kev rhuav tshem cov hydrogen bonds, cov cellulose ether ua dej-soluble tom qab cellulose lattice nthuav dav thiab cov tshuaj nkag mus, tsim cov tshuaj viscosity siab. Thaum qhov kub nce siab, qhov hydration ntawm polymer tsis muaj zog, thiab cov dej ntawm cov saw raug tsav tawm. Thaum cov dehydration effect txaus, cov molecules pib sib sau ua ke, tsim cov qauv network peb-seem gel thiab tais tawm.
Cov yam tseem ceeb uas cuam tshuam rau qhov khaws dej ntawm cov mortar suav nrog cellulose ether viscosity, ntxiv tus nqi, qhov zoo ntawm cov khoom me me thiab siv qhov kub:
Qhov viscosity ntawm cellulose ether ntau dua, qhov zoo dua qhov kev ua tau zoo ntawm kev khaws dej. Viscosity yog ib qho tseem ceeb ntawm MC kev ua tau zoo. Tam sim no, cov chaw tsim khoom MC sib txawv siv ntau txoj kev thiab cov cuab yeej los ntsuas qhov viscosity ntawm MC. Cov txheej txheem tseem ceeb yog Haake Rotovisko, Hoppler, Ubbelohde thiab Brookfield. Rau tib yam khoom, cov txiaj ntsig viscosity ntsuas los ntawm ntau txoj kev sib txawv yog txawv heev, thiab qee qhov txawm tias muaj ob npaug sib txawv. Yog li ntawd, thaum piv viscosity, nws yuav tsum tau ua tiav ntawm tib txoj kev sim, suav nrog kub, rotor, thiab lwm yam.
Feem ntau hais lus, qhov siab dua qhov viscosity, qhov zoo dua qhov dej khaws cia nyhuv. Txawm li cas los xij, qhov siab dua qhov viscosity thiab qhov siab dua qhov hnyav molecular ntawm MC, qhov txo qis hauv nws cov solubility yuav muaj qhov cuam tshuam tsis zoo rau lub zog thiab kev tsim kho ntawm cov mortar. Qhov siab dua qhov viscosity, qhov ntau dua qhov thickening effect ntawm cov mortar, tab sis nws tsis yog proportional ncaj qha. Qhov siab dua qhov viscosity, qhov ntau dua viscosity cov ntub mortar yuav yog, uas yog, thaum lub sijhawm tsim kho, nws yog manifested li lo rau ntawm scraper thiab siab adhesion rau lub substrate. Tab sis nws tsis pab kom nce lub zog ntawm cov ntub mortar nws tus kheej. Thaum lub sijhawm tsim kho, qhov kev ua tau zoo tiv thaiv-sag tsis pom tseeb. Ntawm qhov tsis sib xws, qee qhov nruab nrab thiab qis viscosity tab sis hloov kho methyl cellulose ethers muaj kev ua tau zoo heev hauv kev txhim kho lub zog ntawm cov ntub mortar.
Qhov ntau ntawm cellulose ether ntxiv rau hauv cov mortar, qhov zoo dua qhov kev ua tau zoo ntawm kev khaws dej, thiab qhov siab dua qhov viscosity, qhov zoo dua qhov kev ua tau zoo ntawm kev khaws dej.
Hais txog qhov loj ntawm cov khoom me me, cov khoom me me dua, qhov zoo dua qhov khaws dej. Tom qab cov khoom loj ntawm cellulose ether kov dej, qhov chaw tam sim ntawd yaj thiab tsim cov gel los qhwv cov khoom kom tiv thaiv cov dej molecules los ntawm kev txuas ntxiv mus rau hauv. Qee zaum nws tsis tuaj yeem sib kis thiab yaj txawm tias tom qab do ntev, tsim cov kua flocculent lossis agglomeration. Nws cuam tshuam loj heev rau kev khaws dej ntawm cellulose ether, thiab solubility yog ib qho ntawm cov yam tseem ceeb rau kev xaiv cellulose ether.
Qhov zoo kuj yog ib qho tseem ceeb ntawm kev ua tau zoo ntawm methyl cellulose ether. MC siv rau cov hmoov qhuav yuav tsum yog hmoov, nrog cov dej tsawg, thiab qhov zoo kuj xav tau 20% ~ 60% ntawm qhov loj me ntawm cov khoom me me kom tsawg dua 63um. Qhov zoo cuam tshuam rau qhov solubility ntawm methyl cellulose ether. Coarse MC feem ntau yog granular, thiab nws yooj yim yaj hauv dej yam tsis muaj agglomeration, tab sis qhov nrawm yaj qeeb heev, yog li nws tsis haum rau siv rau hauv cov hmoov qhuav mortar. Hauv cov hmoov qhuav mortar, MC raug tawg ntawm cov ntaub ntawv cementing xws li aggregate, filler zoo thiab cement, thiab tsuas yog hmoov zoo txaus tuaj yeem zam methyl cellulose ether agglomeration thaum sib tov nrog dej. Thaum MC raug ntxiv nrog dej kom yaj cov agglomerates, nws nyuaj heev rau tawg thiab yaj.
Qhov MC uas zoo li tsis zoo tsuas yog ua rau lub zog ntawm cov tshuaj khib tsis zoo xwb, tab sis kuj ua rau lub zog ntawm cov tshuaj khib tsis zoo. Thaum siv cov tshuaj khib qhuav no rau hauv thaj chaw loj, qhov ceev ntawm cov tshuaj khib qhuav hauv zos yuav raug txo qis, thiab yuav muaj kab nrib pleb vim yog lub sijhawm kho sib txawv. Rau cov tshuaj khib uas siv tshuaj tsuag nrog kev tsim kho tshuab, qhov yuav tsum tau ua kom zoo dua vim yog lub sijhawm sib tov luv dua.
Qhov zoo ntawm MC kuj muaj qee qhov cuam tshuam rau nws cov dej khaws cia. Feem ntau hais lus, rau methyl cellulose ethers nrog tib viscosity tab sis sib txawv fineness, nyob rau hauv tib qho ntxiv tus nqi, qhov finer qhov finer qhov zoo dua qhov dej khaws cia nyhuv.
Qhov kev khaws dej ntawm MC kuj muaj feem cuam tshuam nrog qhov kub thiab txias uas siv, thiab qhov kev khaws dej ntawm methyl cellulose ether txo qis nrog rau qhov kub thiab txias nce ntxiv. Txawm li cas los xij, hauv kev siv cov khoom siv tiag tiag, cov hmoov qhuav feem ntau siv rau cov khoom kub ntawm qhov kub siab (siab dua 40 degrees) hauv ntau qhov chaw, xws li kev pleev xim rau phab ntsa sab nraud hauv qab lub hnub thaum lub caij ntuj sov, uas feem ntau ua rau kev kho ntawm cov cement thiab kev ua kom cov hmoov qhuav tawv dua. Qhov kev poob qis ntawm qhov kev khaws dej ua rau muaj kev xav tias ob qho tib si kev ua haujlwm tau zoo thiab kev tiv thaiv tawg raug cuam tshuam, thiab nws yog qhov tseem ceeb heev kom txo qhov cuam tshuam ntawm cov yam ntxwv kub hauv qab qhov xwm txheej no.
Txawm hais tias methyl hydroxyethyl cellulose ether additives tam sim no suav hais tias yog nyob rau pem hauv ntej ntawm kev txhim kho thev naus laus zis, lawv qhov kev vam khom rau qhov kub tseem yuav ua rau qhov kev ua haujlwm ntawm cov hmoov qhuav tsis muaj zog. Txawm hais tias qhov ntau ntawm methyl hydroxyethyl cellulose nce ntxiv (lub caij ntuj sov mis), qhov ua haujlwm tau zoo thiab kev tiv thaiv tawg tseem tsis tuaj yeem ua tau raws li qhov xav tau ntawm kev siv. Los ntawm qee qhov kev kho tshwj xeeb ntawm MC, xws li kev nce qib ntawm etherification, thiab lwm yam, cov dej khaws cia cov nyhuv tuaj yeem tswj tau ntawm qhov kub siab dua, yog li nws tuaj yeem muab kev ua tau zoo dua nyob rau hauv cov xwm txheej hnyav.
3. Kev ua kom tuab thiab Thixotropy ntawm Cellulose Ether
Thickening thiab thixotropy ntawm cellulose ether: Lub luag haujlwm thib ob ntawm cellulose ether - thickening effect nyob ntawm: qib ntawm polymerization ntawm cellulose ether, kev daws teeb meem, shear rate, kub thiab lwm yam mob. Lub zog gelling ntawm cov tshuaj yog tshwj xeeb rau alkyl cellulose thiab nws cov derivatives hloov kho. Cov khoom gelation muaj feem cuam tshuam nrog qib ntawm kev hloov pauv, kev daws teeb meem concentration thiab cov khoom ntxiv. Rau hydroxyalkyl hloov kho derivatives, cov khoom gel kuj muaj feem cuam tshuam nrog qib hloov kho ntawm hydroxyalkyl. Rau cov viscosity qis MC thiab HPMC, 10% -15% kev daws teeb meem tuaj yeem npaj tau, nruab nrab viscosity MC thiab HPMC tuaj yeem npaj tau 5% -10% kev daws teeb meem, thaum viscosity siab MC thiab HPMC tsuas yog tuaj yeem npaj 2% -3% kev daws teeb meem, thiab Feem ntau qhov kev faib tawm viscosity ntawm cellulose ether kuj tau qib los ntawm 1% -2% kev daws teeb meem.
Cov cellulose ether uas muaj qhov hnyav molecular siab muaj qhov ua kom tuab siab. Hauv cov tshuaj concentration tib yam, cov polymers uas muaj qhov hnyav molecular sib txawv muaj viscosities sib txawv. Qib siab. Lub hom phiaj viscosity tsuas yog ua tiav los ntawm kev ntxiv ntau ntawm cov cellulose ether uas muaj qhov hnyav molecular qis. Nws cov viscosity tsis muaj kev vam khom rau qhov nrawm shear, thiab cov viscosity siab ncav cuag lub hom phiaj viscosity, thiab qhov xav tau ntxiv yog me me, thiab cov viscosity nyob ntawm qhov ua kom tuab. Yog li ntawd, kom ua tiav qee qhov sib xws, qee qhov ntawm cellulose ether (kev sib xyaw ntawm cov tshuaj) thiab cov viscosity ntawm cov tshuaj yuav tsum tau lees paub. Qhov kub ntawm cov tshuaj gel kuj txo qis linearly nrog qhov nce ntawm qhov concentration ntawm cov tshuaj, thiab cov gels ntawm chav tsev kub tom qab ncav cuag qee qhov concentration. Qhov concentration gelling ntawm HPMC yog qhov siab heev ntawm chav tsev kub.
Kev sib xws kuj tseem tuaj yeem hloov kho los ntawm kev xaiv qhov loj me ntawm cov khoom me me thiab xaiv cov cellulose ethers nrog ntau qib kev hloov kho. Qhov kev hloov kho hu ua yog qhia txog qee qib ntawm kev hloov pauv ntawm cov pab pawg hydroxyalkyl ntawm cov qauv pob txha ntawm MC. Los ntawm kev hloov pauv cov nqi hloov pauv ntawm ob qho kev hloov pauv, uas yog, DS thiab ms cov nqi hloov pauv ntawm cov pab pawg methoxy thiab hydroxyalkyl uas peb feem ntau hais. Ntau yam kev ua tau zoo ntawm cellulose ether tuaj yeem tau txais los ntawm kev hloov pauv cov nqi hloov pauv ntawm ob qho kev hloov pauv.
Kev sib raug zoo ntawm kev sib xws thiab kev hloov kho: qhov ntxiv ntawm cellulose ether cuam tshuam rau kev siv dej ntawm cov mortar, kev hloov pauv qhov sib piv ntawm dej-binder ntawm dej thiab cement yog qhov ua rau tuab, qhov ntau dua qhov koob tshuaj, qhov ntau dua qhov kev siv dej.
Cov cellulose ethers siv rau hauv cov khoom siv ua hmoov yuav tsum yaj sai sai hauv dej txias thiab muab qhov sib xws tsim nyog rau lub kaw lus. Yog tias muab qee qhov shear rate, nws tseem yuav ua rau flocculent thiab colloidal block, uas yog cov khoom tsis zoo lossis tsis zoo.
Kuj tseem muaj kev sib raug zoo ntawm qhov sib xws ntawm cov cement paste thiab cov koob tshuaj ntawm cellulose ether. Cellulose ether tuaj yeem ua rau kom cov viscosity ntawm mortar ntau ntxiv. Qhov ntau dua qhov koob tshuaj, qhov pom tseeb dua. Cov kua dej cellulose ether uas muaj viscosity siab muaj thixotropy siab, uas kuj yog ib qho tseem ceeb ntawm cellulose ether. Cov kua dej ntawm MC polymers feem ntau muaj pseudoplastic thiab non-thixotropic fluidity qis dua lawv qhov kub gel, tab sis Newtonian ntws cov khoom ntawm qhov qis shear. Pseudoplasticity nce nrog qhov hnyav molecular lossis concentration ntawm cellulose ether, tsis hais hom substituent thiab qib ntawm kev hloov pauv. Yog li ntawd, cellulose ethers ntawm tib qib viscosity, tsis hais MC, HPMC, HEMC, yuav ib txwm qhia tib yam rheological khoom ntev li qhov concentration thiab kub tau khaws cia tas li.
Cov gels qauv tsim thaum qhov kub nce siab, thiab cov dej ntws thixotropic heev tshwm sim. Cov cellulose ethers uas muaj concentration siab thiab viscosity qis qhia thixotropy txawm tias qis dua qhov kub gel. Cov khoom no muaj txiaj ntsig zoo rau kev kho qhov sib npaug thiab sagging hauv kev tsim kho mortar. Nws yuav tsum tau piav qhia ntawm no tias qhov viscosity ntawm cellulose ether siab dua, qhov zoo dua qhov khaws cia dej, tab sis qhov viscosity siab dua, qhov hnyav molecular ntawm cellulose ether siab dua, thiab qhov txo qis hauv nws cov solubility, uas muaj qhov cuam tshuam tsis zoo rau qhov concentration ntawm mortar thiab kev ua haujlwm ntawm kev tsim kho. Qhov viscosity siab dua, qhov pom tseeb dua qhov thickening effect ntawm mortar, tab sis nws tsis yog proportional tag nrho. Qee qhov viscosity nruab nrab thiab qis, tab sis cov cellulose ether hloov kho muaj kev ua tau zoo dua hauv kev txhim kho lub zog ntawm cov mortar ntub. Nrog rau qhov nce ntawm viscosity, qhov khaws cia dej ntawm cellulose ether txhim kho. 4. Kev ncua ntawm cellulose ether
Kev ncua ntawm cellulose ether: Lub luag haujlwm thib peb ntawm cellulose ether yog ncua cov txheej txheem hydration ntawm cement. Cellulose ether muab mortar nrog ntau yam khoom zoo, thiab tseem txo qhov kub hydration thaum ntxov ntawm cement thiab ncua cov txheej txheem hydration dynamic ntawm cement. Qhov no tsis zoo rau kev siv mortar hauv thaj chaw txias. Qhov cuam tshuam retardation no yog tshwm sim los ntawm kev adsorption ntawm cellulose ether molecules ntawm cov khoom hydration xws li CSH thiab ca (OH) 2. Vim yog qhov nce ntawm viscosity ntawm cov kua pore, cellulose ether txo qhov kev txav mus los ntawm cov ions hauv cov kua, yog li ncua cov txheej txheem hydration.
Lub sijhawm tshaj tawm: Lub Ob Hlis-04-2023