Kev npaj ntawm carboxymethyl cellulose

Carboxymethyl cellulose (CMC)yog ib tug ntau yam dej-soluble polymer muab tau los ntawm cellulose, uas yog ib tug natural polysaccharide pom nyob rau hauv cov nroj tsuag cell phab ntsa. CMC pom ntau daim ntawv thov hauv ntau yam lag luam suav nrog zaub mov, tshuaj, tshuaj pleev ib ce, textiles, ntawv, thiab ntau lwm yam vim nws cov khoom tshwj xeeb xws li thickening, stabilizing, binding, film-forming, thiab dej tuav. Kev npaj ntawm CMC suav nrog ntau cov kauj ruam pib los ntawm kev rho tawm ntawm cellulose los ntawm cov khoom siv ntuj tsim ua raws li nws cov kev hloov kho los qhia txog carboxymethyl pawg.

1. Extraction ntawm Cellulose:
Thawj kauj ruam hauv kev npaj CMC yog kev rho tawm ntawm cellulose los ntawm tej yam ntuj tso xws li ntoo pulp, paj rwb linters, los yog lwm yam nroj tsuag fibers. Cov cellulose feem ntau tau txais los ntawm ntau cov txheej txheem xws li pulping, bleaching, thiab purification. Piv txwv li, ntoo pulp tuaj yeem tau los ntawm kev siv tshuab lossis tshuaj lom neeg cov txheej txheem ua raws li cov tshuaj dawb nrog cov tshuaj chlorine lossis hydrogen peroxide kom tshem tawm cov impurities thiab lignin.

2. Ua kom Cellulose:
Thaum cellulose tau muab rho tawm, nws yuav tsum tau qhib kom yooj yim rau kev qhia txog carboxymethyl pawg. Kev ua kom nquag plias yog ua tiav los ntawm kev kho cellulose nrog alkali xws li sodium hydroxide (NaOH) lossis sodium carbonate (Na2CO3) nyob rau hauv kev tswj xyuas qhov kub thiab txias. Kev kho Alkali swells cov cellulose fibers thiab ua rau lawv cov reactivity los ntawm kev rhuav tshem intra thiab intermolecular hydrogen bonds.

3. Carboxymethylation Reaction:
Cov cellulose activated ces raug rau cov tshuaj tiv thaiv carboxymethylation qhov twg carboxymethyl pawg (-CH2COOH) tau nkag mus rau hydroxyl pawg ntawm cellulose chains. Cov tshuaj tiv thaiv no feem ntau yog ua los ntawm kev ua haujlwm ntawm cov cellulose activated nrog sodium monochloroacetate (SMCA) nyob rau hauv muaj cov alkaline catalyst xws li sodium hydroxide (NaOH). Cov tshuaj tiv thaiv tuaj yeem sawv cev raws li hauv qab no:

Cellulose + Chloroacetic Acid → Carboxymethyl Cellulose + NaCl

Cov tshuaj tiv thaiv nrog rau qhov kub thiab txias, lub sij hawm tshuaj tiv thaiv, concentration ntawm reagents, thiab pH yog ua tib zoo tswj xyuas kom muaj cov txiaj ntsig siab thiab qhov xav tau ntawm kev hloov pauv (DS) uas yog hais txog qhov nruab nrab ntawm cov carboxymethyl pawg qhia hauv ib chav tsev ntawm cov cellulose.

4. Neutralization thiab ntxuav:
Tom qab cov tshuaj tiv thaiv carboxymethylation, qhov tshwm sim carboxymethyl cellulose yog neutralized kom tshem tawm ntau tshaj alkali thiab unreacted chloroacetic acid. Qhov no feem ntau ua tiav los ntawm kev ntxuav cov khoom nrog dej los yog cov kua qaub diluted ua raws li kev pom kom cais cov khoom CMC los ntawm cov tshuaj tiv thaiv sib tov.

5. Purification:
CMC purified ces ntxuav nrog dej ntau zaus kom tshem tawm impurities xws li ntsev, unreacted reagents, thiab by-products. Lim lossis centrifugation tuaj yeem ua haujlwm los cais cov CMC purified los ntawm cov dej ntxuav.

6. Qhuav:
Thaum kawg, cov purified carboxymethyl cellulose yog qhuav kom tshem tawm cov seem seem thiab tau txais cov khoom xav tau nyob rau hauv daim ntawv ntawm cov hmoov qhuav los yog granules. Kev ziab tuaj yeem ua tiav siv ntau txoj hauv kev xws li cua kom qhuav, nqus kom qhuav, lossis txau kom qhuav nyob ntawm qhov xav tau ntawm cov khoom kawg.

7. Yam ntxwv thiab Kev Tswj Xyuas Zoo:
Cov qhuavCMCCov khoom yog raug rau ntau yam kev ua cim xws li Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thiab ntsuas viscosity kom paub meej tias nws cov qauv tshuaj, qib kev hloov pauv, qhov hnyav molecular, thiab purity. Kev tswj xyuas kev ua tau zoo kuj tau ua los xyuas kom meej tias cov khoom ua tau raws li qhov xav tau tshwj xeeb rau nws cov ntawv thov.

Kev npaj ntawm carboxymethyl cellulose koom nrog ob peb kauj ruam suav nrog kev rho tawm ntawm cellulose los ntawm cov khoom siv ntuj, kev ua kom muaj zog, carboxymethylation cov tshuaj tiv thaiv, kev ua kom tsis zoo, kev ua kom huv, ziab, thiab kev ua kom zoo. Txhua kauj ruam yuav tsum tau ceev faj tswj cov tshuaj tiv thaiv kab mob thiab tsis ua kom tiav cov txiaj ntsig siab, qhov xav tau ntawm kev hloov pauv, thiab qhov zoo ntawm cov khoom kawg. CMC yog cov khoom siv dav siv polymer nrog ntau hom kev siv vim nws cov khoom tshwj xeeb thiab ntau yam.