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.
Nyob rau hauv npaj txhij cug, ntxiv cov nyiaj ntawm cellulose ether yog tsawg heev, thiab nws yog lub ntsiab ntxiv uas cuam tshuam rau kev ua haujlwm 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.
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 Cov txheej txheem qauv txheej txheem yog [Coh7o2 (Oh) 3-H (OCH3) H] x. Ib feem ntawm pab pawg hydroxyl ntawm chav tsev hloov chaw los ntawm cov pab pawg methoxy yog [C63ch) Nether Hemulrop, cov no yog cov hom neeg tseem ceeb 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, tsis huv thiab zaj dab neeg dispersant thiab ua yeeb yaj kiab.
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 tsuas yog muaj peb yam:
1. Zoo rau dej ua kom muaj peev xwm
2. Cov nyhuv ntawm tshuaj khib sib xws thiab thixotrotropy
3. Kev 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.
Lub Sijhawm Post: Dec-06-2022