1 Kev Taw Qhia
Tam sim no, lub ntsiab raw khoom siv nyob rau hauv kev npaj ntawmcellulose etheryog paj rwb, thiab nws cov zis poob qis, thiab tus nqi kuj nce;
Ntxiv mus, feem ntau siv cov tshuaj etherifying xws li chloroacetic acid (muaj tshuaj lom heev) thiab ethylene oxide (carcinogenic) kuj muaj kev phom sij rau tib neeg lub cev thiab ib puag ncig. Phau ntawv
Hauv tshooj no, cov ntoo thuv cellulose nrog cov txheeb ze purity ntau dua 90% muab rho tawm hauv tshooj thib ob yog siv los ua cov khoom siv raw, thiab sodium chloroacetate thiab 2-chloroethanol yog siv los hloov.
Siv cov tshuaj lom chloroacetic acid ua etherifying tus neeg sawv cev, anioniccarboxymethyl cellulose (CMC), non-ionic hydroxyethyl cellulose tau npaj.
Cellulose (HEC) thiab sib xyaw hydroxyethyl carboxymethyl cellulose (HECMC) peb cellulose ethers. ib yam
Cov txheej txheem kev npaj ntawm peb cellulose ethers tau optimized los ntawm kev sim thiab orthogonal thwmsim, thiab cov synthesized cellulose ethers yog yus muaj los ntawm FT-IR, XRD, H-NMR, thiab lwm yam.
Qhov tseem ceeb ntawm cellulose etherification
Lub hauv paus ntsiab lus ntawm cellulose etherification tuaj yeem muab faib ua ob ntu. Thawj ntu yog txheej txheem alkalization, uas yog, thaum lub sij hawm alkalization ntawm cellulose,
Ib qho kev sib cais nyob rau hauv NaOH tov, ntoo thuv cellulose swells hnyav nyob rau hauv qhov kev txiav txim ntawm txhua yam stirring, thiab nrog nthuav dej.
Ib tug loj npaum li cas ntawm NaOH me me molecules nkag mus rau hauv lub sab hauv ntawm ntoo thuv cellulose, thiab reacted nrog cov hydroxyl pawg ntawm lub nplhaib ntawm cov piam thaj structural unit,
Generates alkali cellulose, lub active chaw ntawm etherification cov tshuaj tiv thaiv.
Qhov thib ob yog cov txheej txheem etherification, uas yog, cov tshuaj tiv thaiv ntawm qhov chaw nquag thiab sodium chloroacetate lossis 2-chloroethanol nyob rau hauv cov xwm txheej alkaline, ua rau
Nyob rau tib lub sijhawm, tus neeg sawv cev etherifying sodium chloroacetate thiab 2-chloroethanol tseem yuav tsim cov dej hauv qab alkaline.
Cov tshuaj tiv thaiv sab yog txiav txim siab los tsim sodium glycolate thiab ethylene glycol, feem.
2 Concentrated alkali decrystallization pretreatment ntawm ntoo thuv cellulose
Ua ntej, npaj ib qho concentration ntawm NaOH tov nrog dej deionized. Tom qab ntawd, ntawm qhov kub thiab txias, 2 g ntawm ntoo thuv fiber
Cov vitamin yog yaj nyob rau hauv ib lub ntim ntawm NaOH tov, nplawm rau ib lub sij hawm, thiab ces lim rau siv.
Tus Qauv Tsim Qauv
Precision pH ntsuas
Collector hom qhov kub thiab txias cua sov magnetic stirrer
Nqus kom qhuav qhov cub
Electronic tshuav nyiaj li cas
Circulating water type multi-purpose nqus tsev vacuum
Fourier Hloov Infrared Spectrometer
X-ray diffractometer
Nuclear Sib Nqus Resonance Spectrometer
Hangzhou Aolilong Instrument Co., Ltd.
Hangzhou Huichuang Instrument Equipment Co., Ltd.
Shanghai Jinghong Experimental Equipment Co., Ltd.
METTLER TOLEDO Instruments (Shanghai) Co., Ltd.
Hangzhou David Science thiab Education Instrument Co., Ltd.
American Thermo Fisher Co., Ltd.
American Thermoelectric Switzerland ARL Lub Tuam Txhab
Swiss tuam txhab BRUKER
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Kev npaj CMCs
Siv ntoo thuv alkali cellulose pretreated los ntawm concentrated alkali decrystallization li raw khoom, siv ethanol ua hnyav thiab siv sodium chloroacetate li 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 khob plaub-caj dab, ces ntxiv ib lub ntim ntawm ethanol hnyav, thiab do zoo rau 30min.
txog, kom cov alkali cellulose yog tag nrho dispersed. Tom qab ntawd ntxiv ib qho nyiaj ntawm alkali tus neeg sawv cev thiab sodium chloroacetate kom hnov mob rau lub sijhawm ntawm qhov kub thiab txias.
Tom qab lub sijhawm, qhov thib ob ntxiv ntawm alkaline tus neeg sawv cev thiab sodium chloroacetate ua raws li etherification rau lub sijhawm. Tom qab cov tshuaj tiv thaiv dhau lawm, txias thiab txias, ces
Neutralize nrog tus nqi tsim nyog ntawm glacial acetic acid, ces nqus lim, ntxuav thiab qhuav.
Kev npaj ntawm HECs
Siv ntoo thuv alkali cellulose pretreated nrog concentrated alkali decrystallization li raw khoom, ethanol li hnyav thiab 2-chloroethanol li etherification
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 ib lub khob plaub-caj dab, thiab ntxiv ib qho ntim ntawm 90% (ntim feem) ethanol, do.
Do rau ib lub sij hawm ntawm lub sij hawm kom tag nrho disperse, ces ntxiv ib tug tej yam nqi ntawm alkali, thiab maj mam cua sov, ntxiv ib co ntim ntawm 2-
Chloroethanol, etherified ntawm qhov kub thiab txias rau ib lub sij hawm, thiab tom qab ntawd ntxiv cov sodium hydroxide thiab 2-chloroethanol ntxiv mus txuas ntxiv etherification rau lub sijhawm. kho
Tom qab cov tshuaj tiv thaiv ua tiav, nruab nrab nrog ib qho nyiaj ntawm glacial acetic acid, thiab thaum kawg lim nrog iav lim (G3), ntxuav, thiab qhuav.
Kev npaj HEMCC
Siv HEC npaj hauv 3.2.3.4 raws li cov khoom siv raw, ethanol ua cov tshuaj tiv thaiv nruab nrab, thiab sodium chloroacetate ua tus neeg sawv cev etherifying los npaj
HECMC. Cov txheej txheem tshwj xeeb yog: noj qee qhov HEC, muab tso rau hauv 100 mL plaub-caj dab, thiab tom qab ntawd ntxiv qee qhov ntim.
90% ethanol, mechanically do rau ib lub sij hawm ntawm lub sij hawm ua kom nws tag nrho dispersed, ntxiv ib tug npaum li cas ntawm alkali tom qab cua sov, thiab maj mam ntxiv.
Sodium chloroacetate, etherification ntawm qhov kub thiab txias tas mus li xaus tom qab lub sijhawm. Tom qab cov tshuaj tiv thaiv tiav lawm, neutralize nws nrog glacial acetic acid rau neutralize nws, ces siv lub iav lim (G3)
Tom qab nqus pom, ntxuav thiab ziab.
Purification ntawm cellulose ethers
Hauv kev npaj cov txheej txheem ntawm cellulose ether, qee cov khoom lag luam feem ntau yog tsim, feem ntau yog cov ntsev inorganic sodium chloride thiab lwm yam.
impurities. Txhawm rau txhim kho qhov zoo ntawm cellulose ether, kev ua kom huv yooj yim tau ua tiav ntawm cov tau txais cellulose ether. vim lawv nyob hauv dej
Muaj ntau cov solubility sib txawv, yog li qhov kev sim siv ib feem ntawm hydrated ethanol los ua kom huv ntawm peb cov cellulose ethers.
hloov.
Muab cov cellulose ether qauv npaj nrog ib qho zoo nyob rau hauv lub beaker, ntxiv ib qho nyiaj ntawm 80% ethanol uas tau preheated rau 60 ℃ ~ 65 ℃, thiab tuav txhua yam stirring ntawm 60 ℃ ~ 65 ℃ ntawm qhov kub thiab txias cua sov magnetic stirrer rau 10 ℃. min. Siv lub supernatant kom qhuav
Hauv ib lub khob huv huv, siv nyiaj nitrate los kuaj xyuas cov chloride ions. Yog hais tias muaj ib tug dawb precipitate, lim nws los ntawm ib lub iav lim thiab coj cov khoom
Rov ua cov kauj ruam dhau los rau lub cev, kom txog rau thaum lub lim dej tom qab ntxiv 1 ncos ntawm AgNO3 cov tshuaj tsis muaj dej dawb, uas yog, kev ua kom huv thiab ntxuav tiav.
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rau hauv (tsuas yog tshem tawm cov tshuaj tiv thaiv los ntawm cov khoom NaCl). Tom qab nqus pom, ziab, txias rau chav tsev kub thiab hnyav.
mas, g.
Test thiab Characterization Methods rau Cellulose Ethers
Kev txiav txim siab ntawm Degree of Hloov (DS) thiab Molar Degree of Hloov (MS)
Kev txiav txim siab ntawm DS: Ua ntej, hnyav 0.2 g (qhov tseeb rau 0.1 mg) ntawm cov qauv purified thiab qhuav cellulose ether, yaj hauv
80mL ntawm cov dej distilled, stirred nyob rau hauv ib tug tas li kub dej da dej ntawm 30 ℃ ~ 40 ℃ rau 10min. Tom qab ntawd kho nrog sulfuric acid tov los yog NaOH tov
pH ntawm cov tshuaj kom txog rau thaum pH ntawm cov tshuaj yog 8. Ces nyob rau hauv ib tug beaker nruab nrog ib tug pH meter electrode, siv ib tug standard tov ntawm sulfuric acid.
Txhawm rau titrate, nyob rau hauv cov xwm txheej nplawm, saib pH meter nyeem ntawv thaum titrating, thaum pH tus nqi ntawm cov tshuaj raug kho rau 3.74,
Lub titration xaus. Nco ntsoov qhov ntim ntawm sulfuric acid txheem tov siv nyob rau lub sijhawm no.
Tiam:
Cov lej ntawm cov lej proton sab saud thiab pawg hydroxyethyl
Qhov piv ntawm tus naj npawb ntawm cov protons sab saud; I7 yog qhov loj ntawm pawg methylene ntawm pawg hydroxyethyl
Kev siv ntawm cov proton resonance ncov; yog qhov kev siv ntawm proton resonance ncov ntawm 5 pawg methine thiab ib pawg methylene ntawm cellulose qabzib units
Saum.
Cov txheej txheem ntsuas tau piav qhia rau kev ntsuas tus cwj pwm infrared ntawm peb lub cellulose ethers CMC, HEC thiab HEECMC
Txoj cai
3.2.4.3 XRD test
X-ray Diffraction Analysis Kev Ntsuas Kev Ntsuas ntawm Peb Cellulose Ethers CMC, HEC thiab HEECMC
txoj kev xeem 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 hnyav, cov tshuaj tau sim los ntawm cov kua hydrogen NMR spectroscopy. Qhov ntsuas zaus yog 75.5MHz.
Sov, cov tshuaj yog 0.5 mL.
3.3 Cov txiaj ntsig thiab Kev Ntsuam Xyuas
3.3.1 Kev ua kom zoo ntawm CMC txheej txheem npaj
Siv cov ntoo thuv cellulose muab rho tawm hauv tshooj thib ob ua cov khoom siv raw, thiab siv sodium chloroacetate ua tus neeg sawv cev etherifying, txoj kev ntawm ib qho kev sim tau txais yuav,
Cov txheej txheem kev npaj ntawm CMC tau ua kom zoo dua qub, thiab thawj qhov sib txawv ntawm qhov kev sim tau teeb tsa raws li qhia hauv Table 3.3. Cov hauv qab no yog txheej txheem kev npaj HEC
Hauv kev kos duab, kev tsom xam ntawm ntau yam.
Table 3.3 Qhov Tseem Ceeb Tseem Ceeb
Factor Tus nqi pib
Pretreatment alkalizing kub / ℃ 40
Pretreatment alkalizing lub sij hawm / h 1
Pretreatment solid-liquid ratio/(g/mL) 1:25
Pretreatment lye concentration /% 40
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Thawj theem etherification kub / ℃ 45
Thawj theem etherification lub sij hawm / h 1
Qhov thib ob theem etherification kub / ℃ 70
Theem ob etherification lub sij hawm / h 1
Lub hauv paus ntau npaum li cas hauv etherification theem / g 2
Tus nqi ntawm etherifying tus neeg sawv cev hauv etherification theem / g 4.3
Etherified solid-liquid ratio / (g / mL) 1:15
3.3.1.1 Kev cuam tshuam ntawm ntau yam ntawm CMC hloov pauv qib hauv pretreatment alkalization theem
1. Cov nyhuv ntawm pretreatment alkalization kub ntawm qhov kev hloov ntawm CMC
Txhawm rau txiav txim siab qhov cuam tshuam ntawm pretreatment alkalization kub ntawm qhov ntsuas ntawm kev hloov pauv hauv CMC tau txais, nyob rau hauv rooj plaub ntawm kev kho lwm yam raws li thawj qhov tseem ceeb,
Raws li cov xwm txheej, cov txiaj ntsig ntawm pretreatment alkalization kub ntawm CMC hloov pauv qib tau tham, thiab cov txiaj ntsig tau qhia hauv daim duab.
Pretreatment alkalizing kub / ℃
Cov nyhuv ntawm pretreatment alkalizing kub ntawm CMC hloov degree
Nws tuaj yeem pom tau tias qhov kev hloov pauv ntawm CMC nce nrog qhov nce ntawm pretreatment alkalization kub, thiab alkalization kub yog 30 ° C.
Qhov saum toj no degrees ntawm kev hloov pauv txo nrog nce kub. Qhov no yog vim qhov kub alkalizing tsawg dhau, thiab cov molecules tsis tshua muaj zog thiab ua tsis tau
Ua kom muaj txiaj ntsig zoo ua rau thaj tsam crystalline ntawm cellulose, uas ua rau nws nyuaj rau tus neeg sawv cev etherifying nkag mus rau sab hauv ntawm cellulose nyob rau theem etherification, thiab qib ntawm cov tshuaj tiv thaiv kuj yog siab heev.
qis, ua rau qis qis ntawm cov khoom hloov pauv. Txawm li cas los xij, qhov kub ntawm alkalization yuav tsum tsis txhob siab dhau. Raws li qhov kub thiab txias, nyob rau hauv qhov kev txiav txim siab kub thiab muaj zog alkali,
Cellulose yog nquag oxidative degradation, thiab qib ntawm kev hloov ntawm cov khoom CMC txo.
2. Kev cuam tshuam ntawm pretreatment alkalinization lub sij hawm ntawm CMC hloov degree
Nyob rau hauv cov xwm txheej uas qhov pretreatment alkalization kub yog 30 ° C thiab lwm yam tseem ceeb yog thawj qhov tseem ceeb, cov nyhuv ntawm pretreatment alkalization lub sij hawm ntawm CMC yog tham.
Cov nyhuv ntawm kev hloov pauv. Degree ntawm kev hloov
Pretreatment alkalizing lub sij hawm / h
Cov nyhuv ntawm pretreatment alkalinization lub sij hawm rauCMChloov degree
Cov txheej txheem bulking nws tus kheej yog qhov nrawm, tab sis cov tshuaj alkali xav tau lub sijhawm diffusion hauv fiber ntau.
Nws tuaj yeem pom tau tias thaum lub sijhawm alkalization yog 0.5-1.5h, qhov hloov pauv ntawm cov khoom nce ntxiv nrog rau lub sijhawm alkalization.
Qhov kev hloov pauv ntawm cov khoom tau txais yog qhov siab tshaj plaws thaum lub sij hawm yog 1.5h, thiab cov degree ntawm kev hloov pauv poob nrog qhov nce ntawm lub sij hawm tom qab 1.5h. Qhov no ua tau
Tej zaum nws yuav yog vim thaum pib ntawm alkalization, nrog rau lub sij hawm ntev ntawm alkalization, infiltration ntawm alkali rau cellulose yog ntau txaus, thiaj li hais tias cov fiber ntau.
Cov qauv tseem ceeb yog so kom txaus, ua rau tus neeg sawv cev etherifying thiab qhov nruab nrab nquag
Post lub sij hawm: Apr-26-2024