1 Kev Taw Qhia
Tam sim no, cov khoom siv tseem ceeb uas siv rau kev npaj cov khoom noj khoom hauscellulose etheryog paj rwb, thiab nws cov zis tawm poob qis, thiab tus nqi kuj nce siab;
Ntxiv mus, cov neeg sawv cev etherifying feem ntau siv xws li chloroacetic acid (muaj tshuaj lom heev) thiab ethylene oxide (ua rau mob qog noj ntshav) kuj ua rau tib neeg lub cev thiab ib puag ncig puas tsuaj ntau dua. Phau Ntawv
Hauv tshooj no, cov cellulose ntoo thuv uas muaj qhov huv ntawm ntau dua 90% uas tau rho tawm hauv tshooj thib ob yog siv ua cov khoom siv raw, thiab sodium chloroacetate thiab 2-chloroethanol yog siv los hloov pauv.
Siv cov tshuaj lom chloroacetic acid ua tus neeg sawv cev etherifying, anioniccarboxymethyl cellulose (CMC), non-ionic hydroxyethyl cellulose tau npaj.
Cellulose (HEC) thiab sib xyaw hydroxyethyl carboxymethyl cellulose (HECMC) peb cellulose ethers. ib qho tseem ceeb
Cov txheej txheem npaj ntawm peb lub cellulose ethers tau raug kho kom zoo los ntawm kev sim thiab kev sim orthogonal, thiab cov cellulose ethers uas tau tsim tau raug cim los ntawm FT-IR, XRD, H-NMR, thiab lwm yam.
Cov hauv paus ntawm cellulose etherification
Lub hauv paus ntsiab lus ntawm cellulose etherification tuaj yeem muab faib ua ob ntu. Thawj ntu yog cov txheej txheem alkalization, uas yog, thaum lub sijhawm alkalization reaction ntawm cellulose,
Sib npaug zos hauv NaOH kua, ntoo thuv cellulose swells violently nyob rau hauv qhov kev ua ntawm kev sib xyaw tshuab, thiab nrog rau kev nthuav dav ntawm dej
Ib qho loj ntawm NaOH me me molecules nkag mus rau hauv sab hauv ntawm cov ntoo thuv cellulose, thiab reacted nrog cov hydroxyl pawg ntawm lub nplhaib ntawm cov glucose structural unit,
Tsim cov alkali cellulose, lub hauv paus tseem ceeb ntawm cov tshuaj etherification.
Qhov thib ob yog cov txheej txheem etherification, uas yog, qhov tshuaj tiv thaiv ntawm lub chaw nquag thiab sodium chloroacetate lossis 2-chloroethanol nyob rau hauv alkaline mob, ua rau
Tib lub sijhawm, tus neeg sawv cev etherifying sodium chloroacetate thiab 2-chloroethanol kuj tseem yuav tsim qee yam dej nyob rau hauv alkaline mob.
Cov tshuaj tiv thaiv sab nraud tau daws teeb meem los tsim cov sodium glycolate thiab ethylene glycol, raws li.
2 Kev kho ua ntej alkali decrystallization ntawm cov ntoo thuv cellulose
Ua ntej, npaj qee qhov concentration ntawm NaOH kua nrog dej deionized. Tom qab ntawd, ntawm qee qhov kub, 2g ntawm cov ntoo thuv fiber
Cov vitamin no yaj rau hauv ib qho ntim ntawm NaOH kua, do rau ib lub sijhawm, thiab tom qab ntawd lim rau kev siv.
Chaw Tsim Khoom Siv Qauv Ntsuas
Kev Ntsuas pH Uas Muaj Kev Ntsuas Zoo
Cov khoom siv sib nqus stirrer kub tas li uas siv cov khoom sib nqus
Qhov cub kom qhuav nrog lub tshuab nqus tsev
Kev sib npaug hluav taws xob
Lub twj tso kua dej ntau hom uas siv dej ncig
Fourier Transform Infrared Spectrometer
Lub tshuab ntsuas hluav taws xob X-ray
Nuclear Magnetic Resonance Spectrometer
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Shanghai Jinghong Experimental Equipment Co., Ltd.
METTLER TOLEDO Cov Cuab Yeej (Shanghai) Co., Ltd.
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Lub Tuam Txhab American Thermoelectric Switzerland ARL
Lub tuam txhab Swiss BRUKER
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Kev npaj cov CMCs
Siv cov ntoo thuv alkali cellulose pretreated los ntawm concentrated alkali decrystallization ua raw khoom, siv ethanol ua cov kuab tshuaj thiab siv sodium chloroacetate ua etherification.
CMC nrog DS siab dua tau npaj los ntawm kev ntxiv alkali ob zaug thiab etherifying tus neeg sawv cev ob zaug. Ntxiv 2g ntawm ntoo thuv alkali cellulose rau hauv lub raj mis plaub-caj dab, tom qab ntawd ntxiv ib qho ntim ntawm ethanol solvent, thiab do kom zoo rau 30 feeb
txog, yog li ntawd cov alkali cellulose tau tawg tag nrho. Tom qab ntawd ntxiv ib qho nyiaj ntawm cov neeg sawv cev alkali thiab sodium chloroacetate kom ua rau muaj kev cuam tshuam rau ib lub sijhawm ntawm qee qhov kub etherification.
Tom qab lub sijhawm, ntxiv ob qho alkaline agent thiab sodium chloroacetate ua raws li etherification rau ib lub sijhawm. Tom qab qhov kev ua haujlwm tiav lawm, txias thiab txias, ces
Siv cov kua qaub glacial acetic acid kom tsis txhob muaj kuab paug, ces lim dej, ntxuav thiab ziab.
Kev Npaj ntawm HECs
Siv cov ntoo thuv alkali cellulose pretreated nrog concentrated alkali decrystallization ua raw khoom, ethanol ua cov kuab tshuaj thiab 2-chloroethanol ua etherification
Lub HEC nrog MS siab dua tau npaj los ntawm kev ntxiv alkali ob zaug thiab etherifying tus neeg sawv cev ob zaug. Ntxiv 2g ntawm ntoo thuv alkali cellulose rau hauv lub raj mis plaub-caj dab, thiab ntxiv qee qhov ntim ntawm 90% (ntim feem) ethanol, do
Do rau ib lub sijhawm kom tag nrho disperse, tom qab ntawd ntxiv ib qho alkali, thiab maj mam ua kom sov, ntxiv ib qho ntim ntawm 2-
Chloroethanol, etherified ntawm qhov kub tas li rau ib lub sijhawm, thiab tom qab ntawd ntxiv cov sodium hydroxide thiab 2-chloroethanol uas seem kom txuas ntxiv etherification rau ib lub sijhawm. kho
Tom qab ua tiav qhov kev ua tshuaj, neutralize nrog ib qho nyiaj ntawm glacial acetic acid, thiab thaum kawg lim nrog lub iav lim (G3), ntxuav, thiab ziab.
Kev Npaj ntawm HEMCC
Siv HEC npaj rau hauv 3.2.3.4 ua cov khoom siv raw, ethanol ua cov tshuaj tiv thaiv, thiab sodium chloroacetate ua tus neeg sawv cev etherifying los npaj
HECMC. Cov txheej txheem tshwj xeeb yog: siv ib qho ntawm HEC, muab tso rau hauv 100 mL plaub-caj dab flask, thiab tom qab ntawd ntxiv ib qho ntawm qhov ntim
90% ethanol, do mechanically rau ib lub sijhawm kom nws dispersed tag nrho, ntxiv ib qho alkali tom qab cua sov, thiab maj mam ntxiv
Sodium chloroacetate, qhov etherification ntawm qhov kub tas li xaus tom qab ib lub sijhawm. Tom qab qhov kev ua tiav, neutralize nws nrog glacial acetic acid kom neutralize nws, tom qab ntawd siv lub iav lim (G3)
Tom qab nqus cov lim dej, ntxuav thiab ziab.
Kev ntxuav cov cellulose ethers
Hauv cov txheej txheem npaj ntawm cellulose ether, qee cov khoom lag luam feem ntau tsim tawm, feem ntau yog cov ntsev inorganic sodium chloride thiab qee qhov lwm yam
cov khoom tsis huv. Yuav kom txhim kho qhov zoo ntawm cellulose ether, kev ntxuav yooj yim tau ua tiav rau ntawm cov cellulose ether tau txais. vim tias lawv nyob hauv dej
Muaj cov solubility sib txawv, yog li qhov kev sim siv qee qhov ntim ntawm hydrated ethanol los ntxuav cov cellulose ethers uas tau npaj tseg.
hloov.
Muab cov qauv cellulose ether uas tau npaj nrog qee yam zoo rau hauv lub beaker, ntxiv qee qhov ntawm 80% ethanol uas tau preheated rau 60 ℃ ~ 65 ℃, thiab tswj kev sib xyaw tshuab ntawm 60 ℃ ~ 65 ℃ ntawm qhov kub tas li cua sov magnetic stirrer rau 10 ℃. feeb. Coj cov supernatant kom qhuav
Hauv ib lub beaker huv si, siv silver nitrate los xyuas seb puas muaj chloride ions. Yog tias muaj cov av dawb, lim nws los ntawm lub lim iav thiab coj cov khoom khov
Rov ua cov kauj ruam dhau los rau lub cev, kom txog thaum cov lim dej tom qab ntxiv 1 tee ntawm AgNO3 kua tsis muaj cov av dawb, uas yog, kev ntxuav thiab ntxuav tiav.
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rau hauv (feem ntau yog kom tshem tawm cov khoom NaCl uas ua rau muaj kev cuam tshuam). Tom qab nqus cov lim dej, ziab, txias rau qhov kub thiab txias hauv chav thiab hnyav.
mass, g.
Cov Txheej Txheem Xeem thiab Kev Txheeb Xyuas rau Cellulose Ethers
Kev Txiav Txim Siab Txog Qib Kev Hloov Chaw (DS) thiab Qib Molar ntawm Kev Hloov Chaw (MS)
Kev txiav txim siab ntawm DS: Ua ntej, hnyav 0.2 g (muaj tseeb txog 0.1 mg) ntawm cov qauv cellulose ether uas tau ntxuav thiab qhuav, yaj nws rau hauv
80mL dej distilled, do hauv dej da dej kub tas li ntawm 30 ℃ ~ 40 ℃ rau 10 feeb. Tom qab ntawd kho nrog sulfuric acid kua lossis NaOH kua.
pH ntawm cov tshuaj kom txog thaum pH ntawm cov tshuaj yog 8. Tom qab ntawd hauv lub beaker uas muaj lub pH meter electrode, siv cov tshuaj sulfuric acid txheem.
Yuav titrate, nyob rau hauv cov xwm txheej sib xyaw, saib qhov nyeem ntawv pH thaum titrating, thaum tus nqi pH ntawm cov tshuaj raug kho rau 3.74,
Qhov kev titration xaus. Nco ntsoov qhov ntim ntawm cov kua sulfuric acid txheem siv rau lub sijhawm no.
Tiam neeg:
Qhov sib sau ua ke ntawm cov lej proton sab saud thiab pawg hydroxyethyl
Qhov piv ntawm tus naj npawb ntawm cov protons sab saud; I7 yog qhov hnyav ntawm pawg methylene ntawm pawg hydroxyethyl
Qhov muaj zog ntawm lub ncov proton resonance; yog qhov muaj zog ntawm lub ncov proton resonance ntawm 5 pawg methine thiab ib pawg methylene ntawm cellulose glucose unit
Tag nrho.
Cov txheej txheem sim tau piav qhia rau kev sim cov yam ntxwv infrared ntawm peb lub cellulose ethers CMC, HEC thiab HEECMC
Txoj Cai
3.2.4.3 Kev sim XRD
Kev Ntsuas Tus Qauv ntawm X-ray Diffraction Analysis ntawm Peb Lub Cellulose Ethers CMC, HEC thiab HEECMC
txoj kev sim uas tau piav qhia.
3.2.4.4 Kev Ntsuas H-NMR
Lub H NMR spectrometer ntawm HEC tau ntsuas los ntawm Avance400 H NMR spectrometer tsim los ntawm BRUKER.
Siv deuterated dimethyl sulfoxide ua cov kuab tshuaj, cov tshuaj tau raug kuaj los ntawm cov kua hydrogen NMR spectroscopy. Lub zaus kuaj yog 75.5MHz.
Sov, cov tshuaj yog 0.5mL.
3.3 Cov Txiaj Ntsig thiab Kev Tshawb Fawb
3.3.1 Kev txhim kho cov txheej txheem npaj CMC
Siv cov ntoo thuv cellulose rho tawm hauv tshooj thib ob ua cov khoom siv raw, thiab siv sodium chloroacetate ua tus neeg sawv cev etherifying, txoj kev sim ib qho tau txais yuav,
Cov txheej txheem npaj ntawm CMC tau raug kho kom zoo, thiab cov hloov pauv pib ntawm qhov kev sim tau teeb tsa raws li tau pom hauv Rooj 3.3. Cov hauv qab no yog cov txheej txheem npaj HEC
Hauv kev kos duab, kev tshuaj xyuas ntawm ntau yam.
Rooj 3.3 Cov Nqi Pib
Tus nqi pib
Kev kho mob ua ntej alkalizing kub / ℃ 40
Lub sijhawm ua ntej alkalizing / h 1
Qhov sib piv ntawm cov khoom khov thiab kua ua ntej kho/(g/mL) 1:25
Kev kho mob ua ntej lye concentration /% 40
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Thawj theem etherification kub / ℃ 45
Lub sijhawm etherification thawj zaug / h 1
Qhov kub thiab txias theem ob ntawm etherification / ℃ 70
Lub sijhawm etherification theem ob / h 1
Cov tshuaj noj hauv theem etherification / g 2
Tus nqi ntawm tus neeg sawv cev etherifying hauv theem etherification / g 4.3
Qhov sib piv ntawm cov khoom khov-kua Etherified / (g / mL) 1:15
3.3.1.1 Kev cuam tshuam ntawm ntau yam tseem ceeb rau qib kev hloov pauv CMC hauv theem ua ntej alkalization
1. Cov nyhuv ntawm qhov kub thiab txias ua ntej kho alkalization rau qib hloov pauv ntawm CMC
Yuav kom xav txog qhov cuam tshuam ntawm qhov kub thiab txias ua ntej kho alkalization rau qib ntawm kev hloov pauv hauv CMC tau txais, yog tias kho lwm yam tseem ceeb ua tus nqi pib,
Nyob rau hauv cov xwm txheej, qhov cuam tshuam ntawm qhov kub thiab txias alkalization ua ntej kho rau CMC substitution degree tau tham txog, thiab cov txiaj ntsig tau qhia nyob rau hauv daim duab.
Kev kho mob ua ntej alkalizing kub / ℃
Cov nyhuv ntawm qhov kub thiab txias ua ntej kho rau CMC substitution degree
Nws tuaj yeem pom tias qib ntawm kev hloov pauv ntawm CMC nce nrog rau qhov nce ntawm qhov kub ua ntej alkalization, thiab qhov kub alkalization yog 30 ° C.
Cov qib saum toj no ntawm kev hloov pauv txo qis nrog rau qhov kub thiab txias nce ntxiv. Qhov no yog vim qhov kub ntawm alkalizing qis dhau, thiab cov molecule tsis tshua muaj zog thiab tsis tuaj yeem ua haujlwm
Ua kom puas tsuaj rau thaj chaw crystalline ntawm cellulose, uas ua rau nws nyuaj rau tus neeg sawv cev etherifying nkag mus rau sab hauv ntawm cellulose hauv theem etherification, thiab qib ntawm kev ua tshuaj tiv thaiv yog qhov siab heev.
qis, ua rau muaj qib qis dua ntawm kev hloov khoom. Txawm li cas los xij, qhov kub ntawm alkalization yuav tsum tsis txhob siab dhau. Thaum qhov kub nce ntxiv, nyob rau hauv qhov kev ua ntawm qhov kub siab thiab muaj zog alkali,
Cellulose yog qhov yooj yim rau oxidative degradation, thiab qib ntawm kev hloov pauv ntawm cov khoom CMC txo qis.
2. Kev cuam tshuam ntawm lub sijhawm ua ntej alkalinization rau CMC hloov chaw degree
Nyob rau hauv qhov xwm txheej uas qhov kub thiab txias ua ntej alkalization yog 30 ° C thiab lwm yam tseem ceeb yog cov nqi pib, cov nyhuv ntawm lub sijhawm ua ntej alkalization rau CMC tau tham txog.
Qhov cuam tshuam ntawm kev hloov pauv. Qib ntawm kev hloov pauv
Lub sijhawm ua ntej alkalizing / teev
Cov nyhuv ntawm lub sijhawm ua ntej alkalinization rauCMCqib hloov pauv
Cov txheej txheem bulking nws tus kheej yog qhov ceev heev, tab sis cov kua alkali xav tau lub sijhawm diffusion hauv cov fiber.
Nws tuaj yeem pom tias thaum lub sijhawm alkalization yog 0.5-1.5 teev, qib hloov pauv ntawm cov khoom nce nrog rau qhov nce ntawm lub sijhawm alkalization.
Qhov degree ntawm kev hloov pauv ntawm cov khoom tau txais yog qhov siab tshaj plaws thaum lub sijhawm yog 1.5 teev, thiab qib ntawm kev hloov pauv txo qis nrog rau kev nce ntawm lub sijhawm tom qab 1.5 teev. Qhov no tuaj yeem
Tej zaum yuav yog vim thaum pib ntawm alkalization, nrog rau lub sijhawm ntev ntawm alkalization, qhov infiltration ntawm alkali rau cellulose yog ntau txaus, yog li ntawd cov fiber
Tus qauv tseem ceeb yog qhov so kom txaus, ua rau tus neeg sawv cev etherifying thiab cov khoom siv nquag nce ntxiv
Lub sijhawm tshaj tawm: Plaub Hlis-26-2024