Cellulose etherification hloov kho

01. Taw qhia txog cellulose

Cellulose yog macromolecular polysaccharide uas muaj cov piam thaj. Insoluble nyob rau hauv dej thiab cov organic solvents. Nws yog cov khoom tseem ceeb ntawm cov phab ntsa ntawm cov nroj tsuag, thiab nws kuj yog qhov dav tshaj plaws thiab muaj ntau tshaj polysaccharide nyob rau hauv cov xwm.

Cellulose yog cov khoom siv txuas ntxiv dua tshiab tshaj plaws hauv ntiaj teb, thiab nws tseem yog cov khoom siv hluav taws xob uas muaj cov khoom loj tshaj plaws. Nws muaj qhov zoo ntawm kev rov ua dua tshiab, ua tiav biodegradable, thiab biocompatibility zoo.

02. Yog vim li cas rau kev hloov cellulose

Cellulose macromolecules muaj ntau pawg -OH. Vim cov nyhuv ntawm hydrogen bonds, lub zog ntawm macromolecules kuj loj, uas yuav ua rau ib tug loj melting enthalpy △H; Ntawm qhov tod tes, muaj cov nplhaib hauv cellulose macromolecules. Zoo li cov qauv, qhov rigidity ntawm cov saw hlau molecular yog ntau dua, uas yuav ua rau me me melting entropy hloov ΔS. Ob qho laj thawj no ua rau qhov kub ntawm cov cellulose molten (= △H / △S ) yuav siab dua, thiab qhov decomposition kub ntawm cellulose kuj tsawg. Yog li ntawd, thaum lub cellulose yog rhuab mus rau ib tug tej yam kub, fibers yuav tshwm sim Qhov tshwm sim uas cov cellulose tau decomposed ua ntej nws pib yaj, yog li ntawd, cov txheej txheem ntawm cov ntaub ntawv cellulose tsis tuaj yeem siv txoj kev ntawm thawj melting thiab ces molding.

03. Qhov tseem ceeb ntawm kev hloov kho cellulose

Nrog rau qhov maj mam depletion ntawm fossil cov peev txheej thiab cov teeb meem loj zuj zus ntawm ib puag ncig los ntawm cov ntaub ntawv pov tseg cov tshuaj fiber ntau, kev txhim kho thiab kev siv cov khoom siv hluav taws xob txuas ntxiv dua tshiab tau dhau los ua ib qho chaw kub uas tib neeg tau saib xyuas. Cellulose yog cov khoom siv hluav taws xob txuas ntxiv dua tshiab tshaj plaws hauv qhov xwm txheej. Nws muaj cov khoom zoo heev xws li zoo hygroscopicity, antistatic, muaj zog huab cua permeability, zoo dyeability, xis hnav, yooj yim textile ua, thiab biodegradability. Nws muaj cov yam ntxwv uas tsis sib piv rau cov tshuaj fibers. .

Cellulose molecules muaj ib tug loj tus naj npawb ntawm hydroxyl pawg, uas yog ib qho yooj yim rau tsim intramolecular thiab intermolecular hydrogen bonds, thiab decompose nyob rau hauv high kub yam tsis melting. Txawm li cas los xij, cellulose muaj qhov ua haujlwm zoo, thiab nws daim ntawv cog lus hydrogen tuaj yeem raug rhuav tshem los ntawm kev hloov kho tshuaj lom neeg lossis cov tshuaj tiv thaiv grafting, uas tuaj yeem txo qhov melting point. Raws li ntau yam khoom lag luam, nws yog dav siv hauv textiles, membrane sib cais, plastics, luam yeeb thiab coatings.

04. Kev hloov kho cellulose etherification

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

Etherification ntawm cellulose yog ib tug series ntawm derivatives ua los ntawm cov tshuaj tiv thaiv ntawm hydroxyl pawg ntawm cov cellulose molecular saw nrog alkylating agents nyob rau hauv alkaline tej yam kev mob. Kev noj ntawm cov pab pawg hydroxyl txo cov naj npawb ntawm cov khoom sib txuas ntawm cov khoom siv hluav taws xob kom txo tau cov kev sib cuam tshuam cov rog, yog li txhim kho cov thermal stability ntawm cellulose, txhim kho kev ua haujlwm ntawm cov ntaub ntawv, thiab tib lub sij hawm txo qhov melting point ntawm cellulose.

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

Siv cov paj rwb refined 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 zoo, siab viscosity, zoo acid tsis kam thiab ntsev tiv thaiv los ntawm alkalization thiab etherification tshua. Siv cov txheej txheem etherification ib-kauj ruam, cov khoom tsim carboxymethyl hydroxypropyl cellulose muaj ntsev zoo, acid tsis kam thiab solubility. Los ntawm kev hloov cov txheeb ze ntawm propylene oxide thiab chloroacetic acid, cov khoom uas muaj carboxymethyl thiab hydroxypropyl sib txawv tuaj yeem npaj tau. Cov txiaj ntsig kev sim qhia tau hais tias cov carboxymethyl hydroxypropyl cellulose uas tsim los ntawm ib-kauj ruam txoj kev muaj lub voj voog luv luv, kev siv cov kuab tshuaj tsawg, thiab cov khoom muaj kev tiv thaiv zoo rau monovalent thiab divalent ntsev thiab cov kua qaub zoo.

05. Kev cia siab ntawm kev hloov kho cellulose etherification

Cellulose yog ib qho tseem ceeb ntawm cov khoom siv tshuaj lom neeg thiab tshuaj lom neeg uas muaj kev nplua nuj nyob hauv cov peev txheej, ntsuab thiab ib puag ncig tus phooj ywg, thiab rov ua dua tshiab. Cov derivatives ntawm cellulose etherification hloov kho muaj kev ua tau zoo, ntau yam kev siv thiab kev siv zoo heev, thiab ua tau raws li cov kev xav tau ntawm lub teb chaws kev lag luam mus rau qhov loj. Thiab cov kev xav tau ntawm kev txhim kho kev sib raug zoo, nrog rau kev ua tiav thev naus laus zis tsis tu ncua thiab kev ua lag luam kev lag luam yav tom ntej, yog tias cov khoom siv hluavtaws thiab cov txheej txheem hluavtaws ntawm cellulose derivatives tuaj yeem ua haujlwm ntau dua, lawv yuav siv tau ntau dua thiab paub txog ntau yam kev siv. . Tus nqi