Kev npaj ntawm cellulose ethers

Kev npaj ntawmcov cellulose etherscuam ​​tshuam nrog kev hloov kho cov tshuaj polymer cellulose ntuj los ntawm kev sib xyaw ua ke ntawm etherification. Cov txheej txheem no qhia txog cov pab pawg ether rau ntawm cov pab pawg hydroxyl ntawm cov saw hlau cellulose polymer, ua rau muaj cov cellulose ethers nrog cov khoom tshwj xeeb. Cov cellulose ethers feem ntau suav nrog Hydroxypropyl Methylcellulose (HPMC), Carboxymethyl Cellulose (CMC), Hydroxyethyl Cellulose (HEC), Methyl Cellulose (MC), thiab Ethyl Cellulose (EC). Nov yog kev piav qhia dav dav ntawm cov txheej txheem npaj:

1. Kev Nrhiav Cellulose:

• Cov txheej txheem pib nrog kev nrhiav cellulose, uas feem ntau yog los ntawm cov ntoo pulp lossis paj rwb. Kev xaiv cov cellulose qhov chaw tuaj yeem cuam tshuam rau cov khoom ntawm cov khoom cellulose ether kawg.

2. Kev ua cov pulp:

• Cov cellulose raug rau cov txheej txheem pulping kom rhuav cov fibers kom yooj yim dua. Qhov no yuav suav nrog cov txheej txheem mechanical lossis tshuaj pulping.

3. Kev ntxuav kom huv:

• Cov cellulose raug ntxuav kom huv si kom tshem tawm cov khoom tsis huv, lignin, thiab lwm yam khoom uas tsis yog cellulosic. Cov kauj ruam ntxuav no yog qhov tseem ceeb rau kev tau txais cov khoom siv cellulose zoo.

4. Kev Ua Haujlwm Etherification:

• Cov cellulose uas tau ntxuav lawm raug etherification, qhov twg cov pawg ether raug qhia rau cov pawg hydroxyl ntawm cov saw hlau cellulose polymer. Kev xaiv ntawm tus neeg sawv cev etherifying thiab cov xwm txheej ntawm cov tshuaj tiv thaiv nyob ntawm cov khoom cellulose ether xav tau.
• Cov neeg sawv cev etherifying feem ntau suav nrog ethylene oxide, propylene oxide, sodium chloroacetate, methyl chloride, thiab lwm yam.

5. Kev Tswj Xyuas Cov Kev Ntsuas Tshuaj:

• Qhov kev ua kom etherification raug tswj hwm kom zoo zoo hauv qhov kub, siab, thiab pH kom ua tiav qib kev hloov pauv (DS) thiab zam kev ua xua.
• Cov xwm txheej alkaline feem ntau siv, thiab pH ntawm cov tshuaj sib tov raug saib xyuas ze.

6. Kev Ua Kom Tsis Muaj Kev Cuam Tshuam thiab Kev Ntxuav:

• Tom qab qhov kev ua etherification, cov khoom feem ntau raug neutralized kom tshem tawm cov reagents lossis cov khoom seem ntau dhau. Cov kauj ruam no yog ua raws li kev ntxuav kom huv si kom tshem tawm cov tshuaj lom neeg thiab cov khoom tsis huv.

7. Kev ziab:

• Cov cellulose uas tau lim thiab etherified raug ziab kom tau txais cov khoom cellulose ether kawg hauv cov hmoov lossis cov ntawv granular.

8. Kev Tswj Xyuas Zoo:

• Muaj ntau txoj kev tshuaj xyuas siv rau kev tswj xyuas zoo, suav nrog nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, thiab chromatography.
• Qhov degree of substitution (DS) yog ib qho tseem ceeb uas tau saib xyuas thaum lub sijhawm tsim khoom kom ntseeg tau tias muaj kev sib xws.

9. Kev Tsim Khoom thiab Ntim Khoom:

• Cov cellulose ether ces raug tsim ua ntau qib sib txawv kom tau raws li qhov xav tau tshwj xeeb ntawm ntau yam kev siv. Cov khoom kawg tau ntim rau kev faib tawm.

Kev npaj cov cellulose ethers yog ib qho txheej txheem tshuaj lom neeg nyuaj uas yuav tsum tau tswj hwm cov xwm txheej ua kom zoo kom ua tiav cov khoom xav tau. Qhov ua tau ntau yam ntawm cellulose ethers tso cai rau lawv siv rau ntau yam kev siv thoob plaws hauv kev lag luam, suav nrog tshuaj, khoom noj, kev tsim kho, txheej, thiab ntau ntxiv.