Super Absorbent Khoom los ntawm Cellulose Ether

Cov txheej txheem thiab cov khoom ua tau zoo ntawm carboxymethyl cellulose cross-linked los ntawm N, N-methylenebisacrylamide los npaj superabsorbent resin tau kawm, thiab cov concentration ntawm alkali, tus nqi ntawm kev sib txuas tus neeg sawv cev, alkali etherification, thiab hnyav tau tham. Cov nyhuv ntawm ntau npaum li cas ntawm cov dej nqus dej ntawm cov khoom. Lub adsorption mechanism ntawm dej-absorbent resin rau dej tau piav qhia. Cov kev tshawb fawb tau pom tias cov dej tuav tus nqi (WRV) ntawm cov khoom no nce mus txog 114ml / g.

Cov lus tseem ceeb:cellulose ether; methylenebisacrylamide; kev npaj

1,Taw qhia

Superabsorbent resin yog cov khoom siv polymer nrog cov pab pawg muaj zog hydrophilic thiab qee qib ntawm kev sib txuas. Cov khoom siv dej nqus dej xws li ntawv, paj rwb, thiab hemp muaj qhov nqus dej tsawg thiab cov dej tsis muaj peev xwm tuav tau, thaum cov khoom siv super-absorbent tuaj yeem nqus dej ntau ntau zaus lawv qhov hnyav, thiab cov gel tsim tom qab nqus dej yuav tsis dehydrate txawm. nrog me ntsis siab. Cov dej tuav tau zoo heev. Nws tsis yog soluble hauv dej lossis hauv cov kuab tshuaj organic.

Muaj ntau pawg hydroxyl pawg, carboxyl pawg thiab sodium hydrate ions ntawm cov saw molecular ntawm super absorbent khoom ua los ntawm cellulose. Tom qab nqus dej, cov dej nyob ib puag ncig los ntawm hydrophilic macromolecular network thiab tuaj yeem khaws cia nyob rau hauv lub siab sab nraud. Thaum dej moistens lub adsorption resin, ib txheej ntawm semi-permeable membrane yog tsim ntawm resin thiab dej. Vim tias qhov siab ntawm cov ions mobile (Na +) hauv cov dej nqus dej, raws li Donnan's equilibrium txoj cai, qhov no ion concentration sib txawv tuaj yeem ua rau osmotic siab. Tsis zoo, tsim lub zog moistening thiab o tsis muaj zog, dej dhau los ntawm cov txheej txheem ntawm cov txheej txheem semi-permeable thiab ua ke nrog hydrophilic pawg thiab ions ntawm macromolecules ntawm superabsorbent resin, txo cov concentration ntawm mobile ions, yog li qhia tau tias muaj dej nqus thiab o. Cov txheej txheem adsorption no txuas ntxiv mus txog rau thaum osmotic siab sib txawv los ntawm qhov sib txawv ntawm qhov sib txawv ntawm cov ions mobile yog sib npaug rau qhov tsis kam mus rau kev nthuav dav ntxiv los ntawm kev sib koom ua ke ntawm cov molecular network ntawm polymer resin. Qhov zoo ntawm superabsorbent resin npaj los ntawm cellulose yog: nruab nrab dej nqus tus nqi, ceev dej nqus ceev, zoo ntsev dej tsis kam, tsis muaj tshuaj lom, yooj yim kho pH tus nqi, tuaj yeem degraded nyob rau hauv qhov, thiab tus nqi qis, yog li nws muaj qhov dav. ntau yam kev siv. Nws tuaj yeem siv los ua tus neeg saib xyuas dej thaiv, cov av txias, thiab cov dej tuav tus neeg saib xyuas hauv kev lag luam thiab kev ua liaj ua teb. Tsis tas li ntawd, nws muaj kev txhim kho zoo thiab kev cia siab rau hauv kev noj qab haus huv, zaub mov, microbiology, thiab tshuaj.

2. Kev sim ib feem

2.1 Kev sim txoj cai

Kev npaj ntawm paj rwb fiber ntau superabsorbent resin yog tsuas yog los tsim ib tug ntoo khaub lig-txuas qauv nrog ib tug tsawg degree ntawm kev hloov nyob rau hauv daim tawv nqaij fiber. Hla-txuas mus rau cov tebchaw uas feem ntau muaj ob lossis ntau pawg ua haujlwm ua haujlwm. Cov pab pawg ua haujlwm muaj peev xwm hla kev sib txuas muaj xws li vinyl, hydroxyl, carboxyl, amide, acid chloride, oxirane, nitrile, thiab lwm yam. Cov dej nqus piv ntawm superabsorbent resins npaj nrog cov sib txuas sib txuas sib txawv. Hauv qhov kev sim no, N, N-methylenebisacrylamide yog siv los ua tus neeg sawv cev sib txuas, suav nrog cov kauj ruam hauv qab no:

(1) Cellulose (Rcell) reacts nrog alkaline tov los tsim alkali cellulose, thiab alkalization cov tshuaj tiv thaiv cellulose yog ib tug ceev exothermic cov tshuaj tiv thaiv. Txo qhov kub thiab txias yog qhov tsim nyog rau kev tsim cov alkali fibers thiab tuaj yeem cuam tshuam lawv cov hydrolysis. Ntxiv cov cawv tuaj yeem ua rau muaj kev cuam tshuam ntawm cellulose, uas muaj txiaj ntsig zoo rau alkalization thiab etherification tom qab.

RcellOH+NaOH→RcellONa + H2O

(2) Alkali cellulose thiab monochloroacetic acid tsim sodium carboxymethyl cellulose, thiab cov tshuaj tiv thaiv etherification belongs rau nucleophilic hloov cov tshuaj tiv thaiv:

RcellONa + ClCH2COONa→RcellOCH2COONa+NaCl

(3) N, N-methylenebisacrylamide cross-linked kom tau txais super absorbent resin. Vim tias tseem muaj ntau pawg hydroxyl nyob rau ntawm cov saw molecular ntawm carboxymethyl fiber, ionization ntawm hydroxyl pawg cellulose thiab ionization ntawm acryloyl ob daim ntawv cog lus ntawm cov saw molecular ntawm N, N-methylenebisacrylamide tuaj yeem tshwm sim nyob rau hauv qhov kev txiav txim. ntawm alkali catalysis, thiab ces Hla-txuas ntawm cellulose molecular chains tshwm sim los ntawm Michael condensation, thiab tam sim ntawd undergoes proton pauv nrog dej los ua ib tug dej-insoluble cellulose superabsorbent resin.

2.2 Cov khoom siv raw thiab cov cuab yeej siv

Cov khoom siv raw: cov paj rwb absorbent (txiav rau hauv linters), sodium hydroxide, monochloroacetic acid, N, N-methylenebisacrylamide, absolute ethanol, acetone.

Cov cuab yeej: peb-caj dab, hluav taws xob nplawm, reflux condenser, nqus lim dej, Buchner funnel, nqus kom qhuav qhov cub, circulating dej nqus twj tso kua mis.

2.3 Txoj kev npaj

2.3.1 Alkalinization

Ntxiv 1 g ntawm cov paj rwb absorbent rau hauv lub raj mis peb-caj dab, tom qab ntawd ntxiv ib qho nyiaj ntawm sodium hydroxide tov thiab ethanol kiag li, ua kom qhov kub thiab txias hauv chav tsev kub, thiab do ib pliag.

2.3.2 Etherification

Ntxiv ib qho nyiaj ntawm chloroacetic acid thiab do rau 1h.

2.3.2 Crosslinking

Nyob rau theem tom ntej ntawm etherification, N, N-methylenebisacrylamide tau ntxiv rau hauv kev faib ua ke kom ua tiav kev sib txuas, thiab nplawm hauv chav sov li 2 teev.

2.3.4 Tom qab ua tiav

Siv glacial acetic acid los kho tus nqi pH mus rau 7, ntxuav cov ntsev nrog ethanol, ntxuav cov dej nrog acetone, lim nrog nqus, thiab nqus kom qhuav rau 4 teev (thaum txog 60).°C, nqus tsev kawm ntawv qib 8.8kPa) kom tau txais cov khoom siv paj rwb dawb.

2.4 Kev ntsuas ntsuas

Tus nqi nqus dej (WRV) yog txiav txim los ntawm sieving, uas yog, 1g ntawm cov khoom (G) yog ntxiv rau lub beaker uas muaj 100ml ntawm distilled dej (V1), soaked rau 24 teev, lim los ntawm 200-mesh stainless hlau screen. , thiab cov dej hauv qab ntawm qhov screen yog sau (V2). Cov mis laij lej yog raws li nram no: WRV = (V1-V2)/G.

3. Cov txiaj ntsig thiab kev sib tham

3.1 Kev xaiv cov tshuaj tiv thaiv alkalization

Nyob rau hauv cov txheej txheem ntawm kev tsim cov alkali cellulose los ntawm kev ua ntawm paj rwb fiber ntau thiab alkaline tov, cov txheej txheem tej yam kev mob muaj feem xyuam rau cov kev ua tau zoo ntawm cov khoom. Muaj ntau yam hauv cov tshuaj tiv thaiv alkalization. Rau qhov yooj yim ntawm kev soj ntsuam, txoj kev sim tsim orthogonal tau txais yuav.

Lwm yam kev mob: Cov kuab tshuaj yog 20ml ntawm cov ethanol, qhov piv ntawm alkali rau etherifying tus neeg sawv cev (mol / md) yog 3: 1, thiab tus neeg sawv cev crosslinking yog 0.05g.

Cov txiaj ntsig kev sim qhia tau tias: kev sib raug zoo ntawm thawj thiab theem nrab: C> A> B, qhov zoo tshaj plaws piv: A3B3C3. Qhov concentration ntawm lye yog qhov tseem ceeb tshaj plaws hauv cov tshuaj tiv thaiv alkalization. Lub siab concentration ntawm lye yog haum rau tsim ntawm alkali cellulose. Txawm li cas los xij, nws yuav tsum tau muab sau tseg tias qhov siab dua qhov concentration ntawm lye, qhov ntau dua cov ntsev cov ntsiab lus ntawm cov npaj superabsorbent resin. Yog li ntawd, thaum ntxuav cov ntsev nrog ethanol, ntxuav nws ob peb zaug kom ntseeg tau tias cov ntsev hauv cov khoom raug tshem tawm, thiaj li tsis cuam tshuam rau lub peev xwm nqus dej ntawm cov khoom.

3.2 Cov nyhuv ntawm crosslinking tus neeg saib xyuas ntau npaum li cas ntawm cov khoom WRV

Cov kev sim yog: 20ml ntawm cov ethanol kiag li, 2.3: 1 piv ntawm alkali rau etherification tus neeg sawv cev, 20ml ntawm lye, thiab 90min ntawm alkalization.

Cov txiaj ntsig tau pom tias tus nqi ntawm tus neeg sawv cev sib txuas tau cuam tshuam rau kev sib txuas ntawm kev sib txuas ntawm CMC-Na. Kev sib txuas ntau dhau ua rau cov qauv sib txuas nruj hauv qhov chaw khoom, uas yog tus cwj pwm los ntawm kev nqus dej tsawg thiab tsis zoo elasticity tom qab nqus dej; thaum tus nqi ntawm tus neeg sawv cev sib txuas me me, qhov sib txuas ntawm qhov sib txuas tsis tiav, thiab muaj cov khoom siv dej-soluble, uas tseem cuam tshuam rau cov dej nqus dej. Thaum tus nqi ntawm tus neeg sawv cev sib txuas tsawg dua 0.06g, tus nqi nqus dej nce ntxiv nrog qhov nce ntawm tus neeg sawv cev sib txuas, thaum tus nqi ntawm tus neeg sawv cev sib txuas ntau dua 0.06g, tus nqi nqus dej txo qis. nrog tus nqi ntawm tus neeg sawv cev sib txuas. Yog li, qhov ntau npaum li cas ntawm tus neeg sawv cev crosslinking yog li 6% ntawm cov paj rwb fiber ntau.

3.3 Qhov cuam tshuam ntawm etherification tej yam kev mob ntawm cov khoom WRV

Cov kev sim yog: alkali concentration 40%; alkali ntim 20 ml; ethanol kiag li 20 ml; cross-linking tus neeg saib xyuas ntau npaum li cas 0.06g; alkalization 90 feeb.

Los ntawm cov tshuaj tiv thaiv kab mob, qhov sib piv ntawm alkali-ether (NaOH: CICH2-COOH) yuav tsum yog 2: 1, tab sis qhov tseeb ntawm alkali siv yog ntau dua li qhov piv txwv no, vim tias qee qhov dawb alkali concentration yuav tsum tau lav nyob rau hauv cov tshuaj tiv thaiv. , vim: tej yam ib tug ntau dua concentration ntawm dawb puag yog conducive rau ua kom tiav cov tshuaj tiv thaiv alkalization; cov tshuaj tiv thaiv kev sib txuas yuav tsum tau ua raws li cov xwm txheej alkaline; Qee qhov kev tawm tsam sab nraud noj alkali. Txawm li cas los xij, yog tias tus nqi ntawm alkali ntxiv ntau dhau lawm, cov alkali fiber ntau yuav raug degraded tiag, thiab tib lub sijhawm, kev ua haujlwm ntawm tus neeg sawv cev etherification yuav raug txo. Kev sim qhia tias qhov piv ntawm alkali rau ether yog li 2.5: 1.

3.4 Kev cuam tshuam ntawm cov kuab tshuaj

Cov kev sim yog: alkali concentration 40%; alkali noj 20 ml; alkali-ether piv 2.5: 1; cross-linking tus neeg saib xyuas ntau npaum li cas 0.06g, alkalization 90min.

Cov kuab tshuaj anhydrous ethanol plays lub luag hauj lwm ntawm dispersing, homogenizing thiab tswj lub slurry lub xeev ntawm lub system, uas yog zoo rau disperse thiab hloov lub tshav kub tso tawm thaum lub sij hawm tsim ntawm alkali cellulose, thiab yuav txo tau cov hydrolysis cov tshuaj tiv thaiv ntawm alkali cellulose, yog li tau txais cov uniform. cellulose. Txawm li cas los xij, yog tias cov cawv ntxiv ntau dhau lawm, cov alkali thiab sodium monochloroacetate yuav yaj hauv nws, qhov concentration ntawm reactants yuav txo qis, cov tshuaj tiv thaiv yuav txo qis, thiab nws tseem yuav muaj kev cuam tshuam tsis zoo rau kev sib txuas txuas ntxiv tom ntej. Thaum tus nqi ntawm ethanol kiag li yog 20ml, WRV tus nqi yog loj.

Hauv cov ntsiab lus, qhov tsim nyog tshaj plaws rau kev npaj superabsorbent resin los ntawm absorbent paj rwb alkalized thiab etherified carboxymethyl cellulose cross-txuas los ntawm N, N-methylenebisacrylamide yog: alkali concentration 40%, hnyav-dawb 20ml dej thiab ethanol, qhov piv ntawm alkali rau ether yog 2.5: 1, thiab ntau npaum li cas ntawm crosslinking tus neeg sawv cev yog 0.06g (6% ntawm cov paj rwb linters).