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. Peb feem ntau siv mc ua monotreether, thiab PMC raws li sib xyaw ethered ether. Methyl Cellulose ether mc yog cov khoom tom qab cov pab pawg hydroxyl ntawm chav dej qab zib ntawm cov methoxy pab pawg. 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, PMC, Hemc, thiab lwm yam, tshuaj, dej txhua hnub txhua hnub, dej tsis tu ncua, dispersant thiab zaj dab neeg sib tw thiab cov yeeb yaj kiab sib txawv.
2. 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. Qhov cuam tshuam rau cov dej khaws cia ntawm cug suav nrog lub viscosity ntawm cellospose ntawm cellws paus ether, qhov nyiaj ntxiv, qhov zoo ntawm cov lus thiab qhov 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 av qhuav rau lub caij ntuj sov, uas feem ntau ua kom nrawm dua ntawm cov cement thiab tawv tawv ntawm cov hmoov av 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.
Lub Sijhawm Post: Mar-04-2023