Hauv kev npaj-sib nphua kab cug, ntxiv cov nyiaj ntawm cellulose yog tsawg, tab sis nws yog lub ntsiab ntxiv uas cuam tshuam kev tsim kho ntawm cug. Cov kev xaiv tsim nyog ntawm cellulose tsim muaj ntau yam, txawv cov viscetle, sib txawv yuav muaj kev sib txawv ntawm kev txhim kho ntawm kev ua kom qhuav. Tam sim no muaj ntau masonry thiab plastering mortars muaj cov dej tsis zoo, thiab cov dej slurry yuav cais tom qab ob peb feeb ntawm sawv ntsug. Dej khaws cia yog ib qho kev ua tau tseem ceeb ntawm methyl cellulose ether, tshwj xeeb yog cov cheeb tsam sib xyaw nrog ntau qhov kub thiab txias, xyuam xim rau. Yam cuam tshuam rau cov dej khaws cov nyhuv kom qhuav ntawm cov tshuaj khib nyiab xws li MC, lub hom phiaj ntawm cov ceg thiab qhov kub ntawm kev siv ib puag ncig.
1. Tswvyim
Cellulose ether yog cov khoom siv hluavtaws tau los ntawm cov xov tooj ntawm lub ntsej muag los ntawm kev hloov kho tshuaj lom neeg. Cellulose ether yog ib qho tseem ceeb ntawm cov cellulose ntuj. Kev tsim cov cellulose ether yog qhov sib txawv los ntawm cov hluavtaws polymers. Nws cov khoom siv tshaj plaws yog cellulose, lub ntuj polymer compound. Vim muaj tshwj xeeb ntawm lub ntuj cellulose qauv, lub cellulose nws tus kheej tsis muaj peev xwm ua kom muaj peev xwm tawm tsam nrog etherification tus sawv cev. Txawm li cas los xij, tom qab kev kho mob ntawm ofing tus neeg sawv cev, cov saw hlau muaj zog los ntawm cov pawg molecular thiab cov koom tes nquag tso tawm, thiab cov pab pawg ua kom nquag plias ntawm cov pab pawg hydroxyl dhau los ua cov alkali cellulose. Muab cov cellulose ether.
Cov yam ntxwv ntawm Cellulose cov neeg muaj kev pab yog nyob ntawm hom, tus lej thiab xa tawm ntawm cov neeg hloov chaw. Kev faib khoom ntawm cov cellulose cov neeg muaj cai kuj yog raws li cov hloov chaw, qib ntawm etherification, solubility thiab suav hais tias cov khoom thov siv tau. Raws li hom kev hloov chaw ntawm cov molecular, nws tuaj yeem faib ua monoet thiab sib xyaw ether. Lub MC peb ib txwm siv yog monoethers, thiab HPMC yog sib xyaw ether. Methyl Cellulose ether mc yog cov khoom tom qab cov pab pawg hydluce Nws yog cov khoom tau los ntawm kev hloov chaw ib feem ntawm cov pab pawg hydroxyl ntawm chav ntsuas nrog pawg methoxy thiab lwm feem nrog cov pab pawg hydroxyprropyl. Cov qauv txheej txheem yog [C6h7o2 (Oh) 3-MN (OCH3) M [OCH2CH (OH) METC, cov no yog cov ntau ntau dav siv thiab muag hauv khw.
Hais txog solubility, nws tuaj yeem faib ua ionic thiab tsis yog ionic. Dej-soluble tsis yog-ionic cellulose cov neeg muaj cai yog tsuas yog suav nrog ob sab ntawm Alkyl uas muaj cov neeg txawj ntse thiab Hydroxyalkyl cov neeg txawj ntse. Ionic CMC feem ntau yog siv nyob rau hauv cov khoom siv hluavtaws, textile luam ntawv thiab tawg thiab roj roj. Tsis yog-ionic mc, HPMC, Hemm, thiab lwm yam, siv tshuaj, dej txhua hnub, stabilizer, dispersant thiab ua yeeb yam disping tus neeg sawv cev.
Thib ob, cov dej khaws cia ntawm cellulose ether
Dej tuav tseg ntawm cellulose ether: hauv kev tsim cov ntaub pua chaw ether etherpacable lub luag haujlwm (kev hloov kho lub cev), nws yog qhov tsis tseem ceeb thiab tseem ceeb.
Lub luag haujlwm tseem ceeb ntawm cov dej-soluble cellulose ether nyob rau hauv cug yog muaj peb qhov yog qhov sib xyaw ua ke, thiab qhov thib peb yog kev sib cuam tshuam nrog cov cement. Cov dej khaws cov nyhuv ntawm cellulose nyob ntawm cov txheej txheem dej, cov dej phib tawj, cov dej phib tawj, thiab lub sijhawm teeb tsa lub sijhawm teeb tsa. Cov dej khaws cia ntawm cellulose ether nws tus kheej los ntawm solubility thiab lub cev qhuav dej ether nws tus kheej. Raws li peb txhua tus paub, txawm hais tias lub cellulose molecular saw muaj ntau ntawm hydratle hel pawg, vim hais tias lub cellulose qauv muaj qhov siab ntawm crystallinity.
Cov hydration muaj peev xwm ntawm pawg hydroxyl ib leeg yog tsis txaus los npog qhov muaj zog hydrogen bonds thiab van der waals rog ntawm molecules. Yog li ntawd, nws tsuas yog swells tab sis tsis yaj hauv dej. Thaum tus hloov pauv tau rau hauv cov molecular chart, tsis tsuas yog cov kev sib tw hydrogen puas tsuaj yog rhuav tshem vim kev sib tw ntawm cov kev sib tw ntawm cov saw hlau. Cov loj dua cov neeg hloov pauv, qhov kev ncua deb ntawm cov lwg me me. Qhov ntau dua qhov deb. Qhov ntau dua cov txiaj ntsig ntawm kev rhuav tshem hydrogen bonds, lub cellulose bonded dej-soluble tom qab lub cellulose daws teeb meem siab. Thaum qhov kub nce, cov hydration ntawm cov polymer muaj zog tsis muaj zog, thiab cov dej ntawm txoj saw hlau tau tsav tawm. Thaum lub cev qhuav dej ua tau txaus, cov lwg me me pib sib sau ua ke, ua ib qho cuab yeej cuab tam sim no thiab tais diav.
Yam cuam tshuam rau cov dej khaws cia ntawm colpe xws li cellulose faib ether viscosity, ntxiv cov nyiaj, particle zoo heev thiab siv ntsuas kub:
Qhov ntau dua viscosity ntawm cellulose ether, qhov zoo dua cov dej khaws cia. Viscosity yog qhov tseem ceeb ntsuas ntawm MC kev ua tau zoo. Ntawm tam sim no, cov cav sib txawv ntawm MC cov qauv sib txawv thiab cov cuab yeej los ntsuas qhov viscosity ntawm MC. Cov hau kev tseem ceeb yog Haake Rotovisko, Woppller, Ubbelihde thiab Brookfield. Rau tib cov khoom lag luam, cov viscosity tau ntsuas los ntawm cov qauv sib txawv yog qhov sib txawv heev, thiab qee tus txawm tau muaj ob npaug sib txawv. Yog li ntawd, thaum piv cov viscosity, nws yuav tsum tau nqa tawm ntawm tib txoj kev ntsuas, suav nrog qhov kub thiab lwm yam.
Feem ntau hais lus, ntau dua cov viscosity, qhov zoo dua cov dej khaws cov nyhuv khaws cia. Txawm li cas los xij, qhov siab tshaj plaws viscosity thiab ntau dua cov molecular hnyav ntawm MC, cov kev coj ua tsis zoo rau lub zog thiab kev tsim kho ntawm lub tshuaj khib. Qhov siab tshaj lub viscosity, qhov pom ntau ntxiv rau cov nyhuv tuab rau ntawm lub tshuaj khib, tab sis nws tsis ncaj ncaj ncaj. Qhov siab tshaj lub viscosity, ntau ntau ntau lub cug cug cug yuav ua, uas yog, thaum lub sijhawm tsim, nws yog manifested raws li straper thiab siab adhesion rau lub substrate. Tab sis nws tsis muaj txiaj ntsig zoo rau kev nce cov txheej txheem lub zog ntawm lub txiv ntoo qhuav nws tus kheej. Thaum kev tsim kho, kev ua haujlwm tsis zoo yog tsis pom tseeb. Ntawm qhov tsis sib xws, qee qhov nruab nrab thiab qis viscosity tab sis hloov kho metyl cellulose cellulose kev ua tau zoo tshaj plaws hauv kev txhim kho lub zog ntawm cov tshuaj khib nyiab ntub dej.
Qhov ntau dua ntawm cov cellulose ether ntxiv rau lub cug lub cug, kom zoo dua cov dej kom ua tau zoo, thiab ntau dua cov dej kom zoo dua.
Hais txog qhov loj me me, cov finer qhov particle, qhov zoo dua cov dej khaws cia. Tom qab cov ntu loj ntawm cellulose ethows tuaj nkag mus rau hauv kev sib cuag nrog cov khoom los tiv thaiv cov roj av lwg me me los ntawm txuas ntxiv mus rau infiltrate. Qee lub sij hawm nws tsis tuaj yeem sib txawv dispersed thiab yaj txawm tias tom qab lub sij hawm ntev plhaw, sib sau cov huab nrog cov huab lossis agglomeration. Nws cuam tshuam heev ntawm cov dej tuav ntawm cellulose ether, thiab solubility yog ib qho ntawm cov cellulose ether.
Fineness tseem yog ib qho kev ua tau tseem ceeb ntsuas ntawm methyl cellulose ether. MC siv rau cov hmoov huv kom qhuav yuav tsum tau ua kom tau hmoov, nrog cov dej hauv dej qis, thiab 60% ntawm qhov me me kom tsawg dua 63um. Cov txiaj ntsig cuam tshuam rau kev solubility ntawm methyl cellulose ether. Kev ntxhib feem ntau yog granular, thiab nws yog ib qho yooj yim kom yaj hauv dej yam tsis muaj agglomeration, tab sis nws tsis haum rau siv hauv cov hmoov av qhuav. Hauv cov hmoov chot, MC tau tawg ntawm cov khoom siv cov txiv ntoo xws li ua kom zoo nkauj thiab ua kom zoo nkauj thiab tsw qab, thiab tsuas yog siv metyl cellulose agglomeration thaum sib xyaw nrog dej. Thaum MC tau ntxiv nrog dej kom yaj lub agglomerates, nws yog qhov nyuaj heev rau kev ntiab tawm thiab yaj.
Ntxhoo Zoo ntawm MC tsis yog tsuas yog khib, tab sis kuj tseem txo lub zog ntawm lub tshuaj khib. Thaum xws li cov hmoov av qhuav tau thov rau hauv thaj chaw loj, tshuaj kho kom txo qis, thiab cov kab nrib pleb yuav tshwm sim vim kev kho tus nqi sib txawv. Rau cov tshuaj khib kab kuab nrog kev tsim kho tshuab, qhov yuav tsum muaj rau kev zoo kawg nkaus yog siab dua vim muaj lub sijhawm sib xyaw luv luv.
Lub txiaj ntsig ntawm MC kuj muaj qee yam cuam tshuam rau nws cov dej khaws cia. Feem ntau hais lus, rau methyl cellulose muaj kev hais nrog tib viscosity tab sis sib txawv tib yam, tus finer qhov zoo dua cov dej ua kom tiav.
Cov dej tuav tseg ntawm MC kuj muaj feem xyuam rau qhov kub siv, thiab cov dej tuav tseg ntawm methyl cellulose nrog qhov ntsuas kub. Txawm li cas los xij, hauv cov ntawv thov cov khoom siv tiag tiag, muab cov hmoov txhuam kom qhuav rau lub hnub sov Tshuaj Khib Dej Qhuav. Kev poob qis ntawm cov dej tuav cia ua rau pom tseeb tias ob qho tib si ua haujlwm thiab tawg tau cuam tshuam yog cuam tshuam rau cov khoom siv kub hauv qab no.
Txawm hais tias methyl hydrotyl cellulose cellulose cais, lawv txoj kev vam khom rau kev ua haujlwm ntawm cov tshuaj khib kom tsis muaj zog. Txawm hais tias tus nqi ntawm methyl hydrothethyl cellulose muaj nce (lub caij ntuj sov formula), kev ua haujlwm lub caij ntuj sov), kev ua haujlwm tsis tuaj yeem ua tau raws li qhov xav tau ntawm kev siv. Los ntawm qee qhov kev kho mob tshwj xeeb rau ntawm MC, xws li nce qib etherification, thiab lwm yam, kom nws tuaj yeem muab kev ua haujlwm zoo hauv qab.
3. Thickening thiab thixotropy ntawm cellulose ether
Thickening thiab thixotropy ntawm cellulose ntawm cellulose thiab qhov thib ob ntawm polymerization ntawm cellule ntawm cellulre ether, shear tus nqi, kub thiab lwm yam kev mob. Cov cuab yeej ntawm cov kev daws teeb meem yog qhov tshwj xeeb rau alkyl cellulose thiab nws tau hloov cov derivatives. Cov khoom gelation muaj feem xyuam nrog rau qib degree hloov chaw, kev daws teeb meem thiab ntxiv. Rau hydroxyalkyl hloov cov derivatives, gel cov khoom tseem muaj feem cuam tshuam nrog kev hloov kho qib ntawm hydroxyalkyl. Rau qis viscosity MC thiab HPMC, 10% -15% kev daws teeb meem MC thiab HPMC tuaj yeem npaj 2% kev daws teeb meem, thiab feem ntau Lub viscosity kev qhia ntawm cellulose ether kuj tseem tau txais graded los ntawm 1% -2% kev daws teeb meem.
High molecular hnyav cellulose muaj siab thicking efficiency. Hauv kev daws teeb meem tib yam, cov polymers nrog hnyav molecular hnyav muaj cov vascosities sib txawv. Siab degree. Lub hom phiaj viscosity tsuas yog ua tiav los ntawm kev ntxiv cov nyiaj ntau ntawm cov roj ntsha tsis muaj roj ether ether. Nws viscosity muaj cov neeg sib txawv me me ntawm cov shear tus nqi, thiab cov viscosity siab txog lub hom phiaj viscosity, thiab viscosity nyob ntawm lub xaim hluav taws xob. Yog li ntawd, kom ua tiav qhov xwm txheej, qee qhov nyiaj ntawm cellulose ether (concentration ntawm kev daws teeb meem) thiab daws viscosity yuav tsum lav. Lub gel kub ntawm kev daws teeb meem tseem txo qis linearly nrog kev nce ntawm cov kev daws teeb meem, thiab gels nyob rau hauv chav tsev kub tom qab ncav ib co siab. Qhov kev pom zoo ntawm HPMC yog qhov siab dua nyob rau hauv chav tsev kub.
Kev sib xws tseem tuaj yeem xaiv tau los ntawm kev xaiv qhov loj me thiab xaiv cov neeg ua haujlwm ntawm cellulose nrog kev hloov kho sib txawv. Lub npe hu ua kev hloov kho yog los qhia qee qib ntawm kev hloov ntawm hydroxyalkyl ntawm lub pob txha txheem ntawm MC. Los ntawm kev hloov pauv tus txheeb ze hloov chaw nyob ntawm ob qho chaw hloov chaw, yog, cov ntawv txheeb ze hloov cov pab pawg uas peb nquag hais. Ntau yam kev ua tau zoo xav tau ntawm cellulose ether tuaj yeem tau los ntawm kev hloov tus txheeb ze hloov chaw ntawm ob qho chaw hloov chaw.
Kev sib raug zoo ntawm kev sib xws thiab hloov kho: ntxiv rau ntawm cellulose cuam tshuam ntawm cov dej caper ntawm cov dej haus, ntau dua qhov ntau npaum li cas, ntau dua cov dej tau noj.
Cov neeg muab kev pab cuam hauv tsev ntawm cov hmoov av yuav tsum yaj tawm hauv dej txias thiab muab ib qho kev ua kom haum rau cov kab ke. Yog tias muab ib qho kev sib tw shear, nws tseem ua cov flocculent thiab colloidal thaiv, uas yog cov khoom lag luam uas tsis muaj cov khoom lag luam tsis zoo.
Kuj tseem muaj cov kab zoo zoo ntawm qhov sib xws ntawm cov cement muab tshuaj pleev thiab cov tshuaj ntawm cellulose ether. Cellulose ether tuaj yeem ua rau muaj viscosity heev ntawm cug. Qhov loj dua cov kev siv tshuaj, qhov tseeb pom tseeb. High-viscosity cellulose ethooure kua muaj siab thixotrostropy, uas tseem yog tus yam ntxwv loj ntawm cellulose ether. Cov kev daws teeb meem aqueous ntawm MC polymers feem ntau muaj pseudopastic thiab tsis-thixotropic fluidity hauv qab no lawv qhov kub thiab txias, tab sis Newtonian Flow cov khoom ntawm cov nqi qis shear. Pseudoplastic nce nrog molecular hnyav lossis concentration ntawm cellulose ether, tsis hais hom kev hloov pauv thiab cov degree hloov chaw. Yog li ntawd, cellulose muaj kev hais ua neeg ntawm tib lub hom phiaj viscosity ntev li ntev tau pom tias muaj qhov siab thiab kub tu tas mus li.
Cov tshuaj pleev cov qauv qauv yog tsim thaum qhov kub tau tsa, thiab muaj txiaj ntsig zoo siab tshaj plaws tshwm sim. Kev siab thiab cov viscosity cellulos cov neeg hais ua ke ua yeeb yam thixotrotropy txawm nyob hauv qab cov pa taws kub. Cov cuab yeej no yog cov txiaj ntsig zoo rau kev hloov kho ntawm leveling thiab sagging hauv kev tsim kho lub tshuab tshuaj khib. Nws yuav tsum tau piav qhia ntawm no tias qhov siab dua ntawm cellulose ntawm cov dej nyob ether ether, thiab cov kev txo qis hauv nws solubility, uas muaj qhov tsis zoo On cug tshuaj masterration thiab kev tsim kho. Qhov siab tshaj lub viscosity, qhov pom ntau ntxiv rau cov nyhuv tuab rau ntawm lub tshuaj khib, tab sis nws tsis yog tag nrho. Qee qhov nruab nrab thiab qis viscosity, tab sis hloov kho cellulose muaj kev ua tau zoo dua hauv kev txhim kho lub zog ntawm lub zog ntub. Nrog rau kev nce viscosity, cov dej khaws cia ntawm cellulose ether txhim kho. 4. Kev rov ua haujlwm ntawm cellulose ether
Kev rov ua haujlwm ntawm cellulose ether: thib peb ua haujlwm ntawm cellulose ether yog ncua cov txheej txheem kev haus hydration ntawm cov cement. Cellulose ether Yuav cug nrog ntau yam tshuaj ntsuab, thiab kuj txo qhov kev ua kom dej sov thiab qeeb cov txheej txheem kev ua kom zoo nkauj ntawm cov cement. Qhov no tsis zoo rau kev siv tshuaj khib hauv cov cheeb tsam txias. Qhov kev ua tau zoo no tshwm sim los ntawm cov adsorption ntawm cellulose ether molecules ntawm cov khoom siv dej xws li CSH thiab Ca (Oh) 2. Vim tias qhov nce nyob rau hauv viscosity ntawm cov kab viscosity ntawm cov kab viscosity, lub cellulose ither txo lub ions hauv kev daws teeb meem, yog li ncua cov txheej txheem hydration.
Lub sijhawm Post: Feb-04-2023