Kev hloov kho cellulose etherification

01. Kev Taw Qhia Txog Cellulose

Cellulose yog ib qho polysaccharide macromolecular uas muaj glucose. Nws tsis yaj hauv dej thiab cov organic solvents. Nws yog lub ntsiab lus tseem ceeb ntawm cov nroj tsuag cell phab ntsa, thiab nws kuj yog cov polysaccharide uas muaj ntau tshaj plaws thiab muaj ntau tshaj plaws hauv xwm.

Cellulose yog cov khoom siv rov ua dua tshiab uas muaj ntau tshaj plaws hauv ntiaj teb, thiab nws kuj yog cov polymer ntuj uas muaj ntau tshaj plaws. Nws muaj qhov zoo ntawm kev rov ua dua tshiab, lwj tag nrho, thiab sib haum xeeb zoo.

02. Vim li cas thiaj hloov kho cellulose

Cellulose macromolecules muaj ntau pawg -OH. Vim yog qhov cuam tshuam ntawm hydrogen bonds, lub zog ntawm macromolecules yog qhov loj heev, uas yuav ua rau muaj qhov loj melting enthalpy △H; ntawm qhov tod tes, muaj cov nplhaib hauv cellulose macromolecules. Zoo li cov qauv, qhov rigidity ntawm cov saw molecular yog qhov loj dua, uas yuav ua rau muaj qhov hloov pauv entropy me dua ΔS. Ob qho laj thawj no ua rau qhov kub ntawm molten cellulose (= △H / △S) yuav siab dua, thiab qhov kub ntawm decomposition ntawm cellulose yog qhov qis dua. Yog li ntawd, thaum cellulose raug cua sov rau qee qhov kub, cov fibers yuav tshwm sim. Qhov tshwm sim uas cellulose tau decomposed ua ntej nws pib yaj, yog li ntawd, kev ua cov ntaub ntawv cellulose tsis tuaj yeem siv txoj kev ntawm thawj melting thiab tom qab ntawd molding.

03. Qhov tseem ceeb ntawm kev hloov kho cellulose

Nrog rau kev siv cov khoom siv fossil maj mam thiab cov teeb meem ib puag ncig loj zuj zus los ntawm cov khib nyiab tshuaj fiber textiles, kev tsim kho thiab kev siv cov khoom siv fiber rov ua dua tshiab tau dhau los ua ib qho chaw kub uas tib neeg them sai sai rau. Cellulose yog cov khoom siv rov ua dua tshiab ntau tshaj plaws hauv xwm. Nws muaj cov khoom zoo heev xws li hygroscopicity zoo, antistatic, muaj zog permeability, dyeability zoo, hnav xis nyob, yooj yim ua textile, thiab biodegradability. Nws muaj cov yam ntxwv uas tsis muaj qhov sib piv rau cov tshuaj fibers. .

Cov cellulose molecule muaj ntau pawg hydroxyl, uas yooj yim los tsim cov intramolecular thiab intermolecular hydrogen bonds, thiab decompose ntawm qhov kub siab yam tsis yaj. Txawm li cas los xij, cellulose muaj reactivity zoo, thiab nws cov hydrogen bond tuaj yeem raug rhuav tshem los ntawm kev hloov kho tshuaj lossis grafting reaction, uas tuaj yeem txo qhov melting point. Raws li ntau yam khoom lag luam, nws yog dav siv hauv textiles, membrane sib cais, plastics, haus luam yeeb thiab coatings.

04. Kev hloov kho cellulose etherification

Cellulose ether yog ib hom cellulose derivative tau los ntawm kev hloov kho cellulose etherification. Nws yog dav siv vim nws zoo heev thickening, emulsification, suspension, zaj duab xis tsim, tiv thaiv colloid, noo noo khaws cia, thiab adhesion zog. Siv rau hauv cov khoom noj, tshuaj, ntawv ua, xim, cov ntaub ntawv tsim kho, thiab lwm yam.

Kev sib xyaw ua ke ntawm cellulose yog ib qho ntawm cov khoom tsim los ntawm kev sib xyaw ua ke ntawm cov pab pawg hydroxyl ntawm cov saw hlau cellulose nrog cov neeg sawv cev alkylating hauv qab alkaline. Kev siv cov pab pawg hydroxyl txo cov naj npawb ntawm cov hydrogen bonds intermolecular kom txo cov zog intermolecular, yog li txhim kho qhov ruaj khov ntawm cellulose, txhim kho kev ua haujlwm ntawm cov ntaub ntawv, thiab tib lub sijhawm txo qhov melting point ntawm cellulose.

Piv txwv ntawm cov teebmeem ntawm kev hloov kho etherification rau lwm yam haujlwm ntawm cellulose:

Siv cov paj rwb ua cov khoom siv raw, cov kws tshawb fawb tau siv cov txheej txheem etherification ib kauj ruam los npaj carboxymethyl hydroxypropyl cellulose complex ether nrog cov tshuaj tiv thaiv sib xws, viscosity siab, tiv taus acid zoo thiab tiv taus ntsev los ntawm alkalization thiab etherification reactions. Siv cov txheej txheem etherification ib kauj ruam, cov carboxymethyl hydroxypropyl cellulose uas tsim tawm muaj cov tshuaj tiv thaiv ntsev zoo, tiv taus acid thiab solubility. Los ntawm kev hloov cov nqi sib piv ntawm propylene oxide thiab chloroacetic acid, cov khoom uas muaj cov ntsiab lus carboxymethyl thiab hydroxypropyl sib txawv tuaj yeem npaj tau. Cov txiaj ntsig ntawm kev sim qhia tau tias carboxymethyl hydroxypropyl cellulose uas tsim los ntawm ib kauj ruam muaj lub voj voog luv luv, kev siv cov kuab tshuaj tsawg, thiab cov khoom muaj kev tiv taus zoo rau cov ntsev monovalent thiab divalent thiab tiv taus acid zoo.

05. Kev cia siab ntawm kev hloov pauv cellulose etherification

Cellulose yog ib qho tseem ceeb ntawm cov tshuaj lom neeg thiab cov khoom siv raw uas muaj ntau yam khoom siv, ntsuab thiab zoo rau ib puag ncig, thiab rov ua dua tshiab. Cov derivatives ntawm cellulose etherification hloov kho muaj kev ua tau zoo heev, ntau yam kev siv thiab cov txiaj ntsig zoo heev, thiab ua tau raws li qhov xav tau ntawm lub teb chaws kev lag luam rau ntau yam. Thiab cov kev xav tau ntawm kev txhim kho hauv zej zog, nrog rau kev nce qib ntawm thev naus laus zis thiab kev paub txog kev lag luam yav tom ntej, yog tias cov khoom siv raw khoom thiab cov txheej txheem hluavtaws ntawm cellulose derivatives tuaj yeem ua lag luam ntau dua, lawv yuav raug siv ntau dua thiab paub txog ntau yam kev siv. Tus nqi