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 mono ether thiab sib xyaw ether. Peb feem ntau siv mc ua mono ether, thiab hpmc raws li sib xyaw ether. Methyl Cellulose ether mc yog cov khoom tom qab cov pab pawg hydroxyl ntawm chav dej qab zib ntawm cov methoxy pab pawg. Cov txheej txheem txheej txheem yog [co h7o2 (Oh) 3-H (OCH3) H] nws tau los ntawm cov pab pawg hydroxy thiab lwm feem nrog cov pab pawg hydroxyprroproutyl. Cov qauv txheej txheem yog [C6h7o2 (Oh) 3-MN (OCH3)-OH) C3] NEETS WEMCELLUE 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, hemc, thiab lwm yam. Feem ntau yog siv nyob rau hauv cov ntaub ntawv hauv tsev, tshuaj, tshuaj noj, txhua hnub tshuaj thiab lwm hnub. Siv ua cov thickener, dej tuav tus neeg sawv cev, stabilizer, dispersant thiab ua yeeb yaj duab sib sau tus neeg sawv cev.
Dej tuav tseg ntawm cellulose ether
Hauv kev tsim cov ntaub ntawv hauv tsev, tshwj xeeb tshaj yog cov cellulose cattrose, tshwj xeeb tshaj yog hauv kev tsim cov cug cug (capified cug), nws yog qhov 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. Nws yog qhov paub zoo tias txawm hais tias lub cellulose molecular chart muaj ntau ntawm hydratle hel pawg, vim hais tias lub cellulose qauv muaj qib 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 siab dua viscosity ntawm cellulose ether, qhov zoo dua cov dej khaws cia, thiab ntau dua viscer daws. Nyob ntawm cov molecular hnyav (polymerization degree) ntawm cov qauv ntev ntawm cov qauv molecular thiab cov khoom faib tawm kuj cuam tshuam nrog nws hom viscosity.
[η] = km α
[η] intrinsic viscosity ntawm polymer daws
m polymer molecular hnyav
lus polymer yam ntxwv tsis tu ncua
K viscosity Tib Coefficient
Lub viscire ntawm cov polymer yog nyob ntawm qhov hnyav molecular ntawm cov polymer. Lub viscosity thiab concentration ntawm cellulose cellulose cellulose muaj kev daws teeb meem ntsig txog daim ntawv thov hauv ntau thaj teb. Yog li no, txhua cellulose ether muaj ntau qhov txawv viscosity, thiab kev hloov kho ntawm alkali cellulose, uas yog, kev tawg ntawm cellulose molecular chains.
Nws tuaj yeem pom los ntawm daim duab 1.2 Koj qhov ntau dua cov cellulose ether ntxiv rau lub capulose, thiab ntau dua cov viscosity, qhov zoo dua cov dej khaws cia.
Rau qhov loj me me, lub finer rau particle, qhov zoo dua cov dej rov qab saib cov khoom siv los tiv thaiv cov roj av lwg me me los ntawm kev tsis taus dej. 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 ntau rau cov dej tuav ntawm nws cov cellulose ether, thiab solubility yog ib qho ntawm cov cellulose ether.
Thickening thiab thixotropy ntawm cellulose ether
Qhov thib ob muaj nuj nqi ntawm cellulose thib ob - tuab nyob ntawm: Qib ntawm polymerization ntawm cellulation ntawm cellulation, kev daws teeb meem, 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. For mc and HPMC with low viscosity, 10%-15% concentration solution can be prepared, 5%-10% solution can be prepared for medium viscosity mc and HPMC, and 2%-3% solution can be prepared for high viscosity mc and HPMC, and usually the viscosity classification of cellulose ether is also graded with 1%-2% solution. High-molecular-phaus cellulose ether muaj siab thicking efficiency. Polymers nrog hnyav molecular hnyav muaj viscosities txawv nyob rau hauv tib lub ntsiab lus daws. 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. Lub gelation concentration ntawm HPMC muaj 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.
Los ntawm Daim Duab 4 peb tuaj yeem pom cov kev sib txheeb ntawm kev sib raug zoo thiab kev hloov kho. Qhov kev sib ntxiv ntawm cellulose ether hauv Daim Duab 5 cuam tshuam rau kev siv dej ntawm cov tshuaj khib thiab hloov cov dej-rau-xis mas piv, uas yog cov nyhuv tuab. Qhov siab dua qhov ntau npaum li cas, qhov ntau dua cov dej 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 ntawm cov nyhuv, saib Daim Duab 6.
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 hom polymers feem ntau muaj pseudopastic thiab tsis yog-thixotropic fluidity hauv qab no lawv qhov kub thiab txias, tab sis Newtonian ntws tawm ntawm cov nqi qis. 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 ntau dua cov viscosity ntawm cellulose kev cia siab, thiab ntau dua cov neeg txheeb ze, uas muaj qhov tsis zoo ntawm cov tshuaj khib kev ua haujlwm. 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.
Lub Sijhawm Post: Feb-18-2023