Hauv cov capulle qhuav, cellulose qhia lub luag haujlwm ntawm dej khaws cia, thickening thiab thixotrostropy, huab cua-entraining thiab retarding yam ntxwv. Cov dej ua kom zoo ua rau muaj kev sib xyaw ua ke ntawm cov tshuaj khib nyiab ntxiv, nws tuaj yeem txhim kho lub sijhawm qhib thiab kho lub sijhawm. Ntxiv cov cellulose ether rau cov tshuab txau tshuaj yuav txhim kho cov qauv txheej txheem ntawm lub cug. Kev ntsuas tus kheej tau tuaj yeem tiv thaiv kev sib hais haum, cais thiab stratification, thiab lwm yam yog siv dav hauv cov tshuaj pleev hmoov kom qhuav. Txhawm rau muab kev ua si tag nrho rau daim ntawv thov ntawm cellulose ether hauv tov colle tov, nws kuj tseem yog qhov tseem ceeb los xaiv hom cellulose ether thiab txiav txim nws daim ntawv thov.
1. Dej tuav ntawm cellulose ether
Tam sim no cov viscosity ntau dua ether ether, qhov zoo dua cov dej cia ua kev ua tau zoo, thiab viscer ntawm polymer tov. Ua raws li cov molecular hnyav (polymerization degree) ntawm cov qauv ntev ntawm cov qauv molecular thiab cov khoom faib ntawm cov khoom hloov kuj tseem cuam tshuam nrog nws cov viscosity ntau.
Tam sim ntawd ntau dua tus nqi ntawm cov cellulose ether ntxiv rau hauv 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, lub finer rau particle, qhov zoo dua cov dej khaws cia. Tom qab cov ntu loj ntawm cellulose ethows tuaj yeem nkag mus rau hauv kev sib cuag nrog cov khoom siv kom tiv thaiv cov roj av ntawm infiltrating. 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.
2. 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 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 muaj siab dua nyob rau hauv chav tsev kub.
Kev sib xws tseem tuaj yeem tuaj yeem xaiv los ntawm xaiv cov particle me me thiab xaiv cov cellulose muaj kev hais txaus nrog qib kev hloov kho. Lub npe hu ua kev hloov kho yog los qhia txog cov pab pawg hydroxyalkyl nrog qee cov qib ntawm kev hloov pauv ntawm pob txha pob txha pob txha pob txha pob ntseg 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.
Qhov kev sib ntxiv ntawm cov cellulose ether 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.
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: Mar-14-2023