Kev npaj ntawm carboxymethyl cellulose

Carboxymethyl cellulose (CMC)yog ib qho polymer uas yaj tau hauv dej uas tau los ntawm cellulose, uas yog ib qho polysaccharide ntuj uas pom muaj nyob rau hauv cov phab ntsa cell ntawm cov nroj tsuag. CMC pom muaj 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 water retention. Kev npaj CMC muaj ntau kauj ruam pib los ntawm kev rho tawm ntawm cellulose los ntawm cov chaw ntuj ua raws li nws txoj kev hloov kho kom qhia txog carboxymethyl pawg.

1. Kev rho tawm ntawm Cellulose:
Kauj ruam thawj zaug hauv kev npaj CMC yog kev rho tawm cov cellulose los ntawm cov khoom siv ntuj xws li cov ntoo pulp, paj rwb linters, lossis lwm yam nroj tsuag fibers. Cov cellulose feem ntau tau txais los ntawm ntau yam txheej txheem suav nrog pulping, bleaching, thiab purification. Piv txwv li, ntoo pulp tuaj yeem tau txais los ntawm cov txheej txheem mechanical lossis tshuaj pulping ua raws li bleaching nrog chlorine lossis hydrogen peroxide kom tshem tawm cov impurities thiab lignin.

2. Kev Ua Haujlwm ntawm Cellulose:
Thaum cellulose raug rho tawm lawm, nws yuav tsum tau ua kom nquag siv los pab txhawb kev qhia txog cov pab pawg carboxymethyl. Kev ua kom nquag siv feem ntau yog ua tiav los ntawm kev kho cellulose nrog alkali xws li sodium hydroxide (NaOH) lossis sodium carbonate (Na2CO3) nyob rau hauv kev tswj hwm ntawm qhov kub thiab txias. Kev kho alkali ua rau cov cellulose fibers o thiab ua rau lawv cov tshuaj tiv thaiv ntau ntxiv los ntawm kev rhuav tshem cov hydrogen bonds sab hauv thiab intermolecular.

3. Kev Sib Tshuam Carboxymethylation:
Cov cellulose uas tau ua haujlwm lawm ces raug rau qhov kev sib xyaw ua ke ntawm carboxymethylation qhov twg cov carboxymethyl pawg (-CH2COOH) raug coj mus rau hauv cov pab pawg hydroxyl ntawm cov saw cellulose. Qhov kev sib xyaw ua ke no feem ntau yog ua los ntawm kev sib xyaw cov cellulose uas tau ua haujlwm nrog sodium monochloroacetate (SMCA) nyob rau hauv qhov muaj cov tshuaj alkaline xws li sodium hydroxide (NaOH). Qhov kev sib xyaw ua ke tuaj yeem sawv cev raws li hauv qab no:

Cellulose + Chloroacetic Acid → Carboxymethyl Cellulose + NaCl

Cov xwm txheej tshuaj tiv thaiv suav nrog qhov kub thiab txias, lub sijhawm tshuaj tiv thaiv, qhov concentration ntawm cov tshuaj reagents, thiab pH raug tswj hwm kom zoo kom ntseeg tau tias muaj txiaj ntsig zoo thiab qib kev hloov pauv (DS) uas xav tau uas yog hais txog tus lej nruab nrab ntawm cov carboxymethyl pawg uas tau qhia rau ib chav glucose ntawm cellulose saw.

4. Kev Ua Kom Tsis Muaj Kev Cuam Tshuam thiab Kev Ntxuav:
Tom qab qhov kev sib xyaw ua ke ntawm carboxymethylation, cov carboxymethyl cellulose uas tshwm sim tau raug tshem tawm kom tshem tawm cov alkali ntau dhau thiab cov kua qaub chloroacetic uas tsis tau ua haujlwm. Qhov no feem ntau ua tiav los ntawm kev ntxuav cov khoom nrog dej lossis cov kua qaub dilute ua raws li kev lim dej kom cais cov khoom CMC khov ntawm cov tshuaj sib xyaw ua ke.

5. Kev ntxuav kom huv:
Cov CMC uas tau ntxuav lawm ces ntxuav nrog dej ntau zaus kom tshem tawm cov khoom tsis huv xws li ntsev, cov tshuaj reagents uas tsis tau ua haujlwm, thiab cov khoom seem. Kev lim dej lossis centrifugation yuav siv tau los cais cov CMC uas tau ntxuav lawm ntawm cov dej ntxuav.

6. Kev ziab:
Thaum kawg, cov carboxymethyl cellulose uas tau lim lawm raug ziab kom tshem tawm cov dej noo seem thiab tau txais cov khoom xav tau hauv daim ntawv ntawm cov hmoov qhuav lossis cov hmoov me me. Kev ziab tuaj yeem ua tiav los ntawm ntau txoj kev xws li ziab cua, ziab nqus tsev, lossis ziab tshuaj tsuag nyob ntawm cov yam ntxwv xav tau ntawm cov khoom kawg.

7. Kev Txheeb Xyuas Tus Yam Ntxwv thiab Kev Tswj Xyuas Zoo:
Cov qhuavCMCcov khoom raug rau ntau yam txheej txheem kev piav qhia xws li Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), thiab viscosity ntsuas kom paub meej nws cov qauv tshuaj, qib ntawm kev hloov pauv, qhov hnyav molecular, thiab kev dawb huv. Kev ntsuam xyuas kev tswj hwm zoo kuj tau ua kom ntseeg tau tias cov khoom ua tau raws li cov lus qhia xav tau rau nws cov ntawv thov.

Kev npaj cov carboxymethyl cellulose muaj ntau kauj ruam suav nrog kev rho tawm cov cellulose los ntawm cov khoom siv ntuj, kev ua kom muaj zog, kev ua kom cov tshuaj tiv thaiv carboxymethylation, kev ua kom tsis muaj zog, kev ntxuav kom huv, kev ziab, thiab kev piav qhia. Txhua kauj ruam yuav tsum tau tswj hwm cov xwm txheej thiab cov kev cai kom ua tiav cov txiaj ntsig siab, qib kev hloov pauv xav tau, thiab qhov zoo ntawm cov khoom kawg. CMC yog cov polymer siv dav dav nrog ntau yam kev siv vim nws cov khoom tshwj xeeb thiab kev hloov pauv tau yooj yim.