Methylcellulose (MC) yog ib hom cellulose ether. Cov tshuaj cellulose ether yog cov derivatives tau los ntawm kev hloov kho tshuaj ntawm cov cellulose ntuj, thiab methylcellulose yog ib qho tseem ceeb cellulose derivative tsim los ntawm methylating (methyl hloov chaw) qhov hydroxyl ntawm cellulose. Yog li ntawd, methylcellulose tsis yog tsuas yog cellulose derivative, tab sis kuj yog ib qho cellulose ether ib txwm muaj.
1. Kev npaj ntawm methylcellulose
Methylcellulose yog npaj los ntawm kev sib xyaw cellulose nrog tus neeg sawv cev methylating (xws li methyl chloride lossis dimethyl sulfate) nyob rau hauv alkaline mob kom methylate qhov hydroxyl ntawm cellulose. Qhov kev sib xyaw no feem ntau tshwm sim ntawm cov pab pawg hydroxyl ntawm C2, C3 thiab C6 txoj haujlwm ntawm cellulose los tsim methylcellulose nrog ntau qib ntawm kev hloov pauv. Cov txheej txheem sib xyaw yog raws li nram no:
Cellulose (ib qho polysaccharide uas muaj cov glucose units) yog thawj zaug ua haujlwm nyob rau hauv alkaline mob;
Tom qab ntawd tus neeg sawv cev methylating raug qhia kom dhau los ua qhov kev sib xyaw ua ke kom tau txais methylcellulose.
Txoj kev no tuaj yeem tsim cov khoom methylcellulose nrog cov viscosities thiab solubility sib txawv los ntawm kev tswj hwm cov xwm txheej ntawm cov tshuaj tiv thaiv thiab qib ntawm methylation.
2. Cov khoom ntawm methylcellulose
Methylcellulose muaj cov yam ntxwv tseem ceeb hauv qab no:
Kev yaj: Tsis zoo li cov cellulose ntuj, methylcellulose tuaj yeem yaj rau hauv dej txias tab sis tsis yog hauv dej kub. Qhov no yog vim tias kev qhia txog methyl substituents rhuav tshem cov hydrogen bonds ntawm cellulose molecules, yog li txo nws cov crystallinity. Methylcellulose tsim cov tshuaj pob tshab hauv dej thiab ua kom pom cov yam ntxwv gelation ntawm qhov kub siab, uas yog, cov tshuaj tuab thaum cua sov thiab rov qab tau cov kua tom qab txias.
Tsis muaj tshuaj lom: Methylcellulose tsis muaj tshuaj lom thiab tib neeg lub cev zom zaub mov tsis nqus tau. Yog li ntawd, nws feem ntau siv rau hauv cov khoom noj thiab cov tshuaj ntxiv ua cov khoom ua kom tuab, emulsifier thiab stabilizer.
Kev tswj hwm viscosity: Methylcellulose muaj cov yam ntxwv tswj hwm viscosity zoo, thiab nws cov viscosity ntawm cov tshuaj muaj feem cuam tshuam nrog qhov concentration ntawm cov tshuaj thiab qhov hnyav molecular. Los ntawm kev tswj hwm qib ntawm kev hloov pauv hauv cov tshuaj etherification, cov khoom methylcellulose nrog ntau yam viscosity tuaj yeem tau txais.
3. Kev siv cov methylcellulose
Vim nws cov khoom siv lub cev thiab tshuaj lom neeg tshwj xeeb, methylcellulose tau siv dav hauv ntau yam lag luam.
3.1 Kev lag luam zaub mov
Methylcellulose yog ib yam khoom noj khoom haus uas siv ntau hauv ntau yam kev ua zaub mov, feem ntau yog ua kom tuab, ua kom emulsifier thiab ua kom ruaj khov. Vim tias methylcellulose tuaj yeem ua gel thaum raug cua sov thiab rov qab ua kom du tom qab txias, nws feem ntau siv rau hauv cov zaub mov khov, cov khoom ci thiab cov kua zaub. Tsis tas li ntawd, qhov xwm txheej qis calorie ntawm methylcellulose ua rau nws yog ib qho khoom xyaw tseem ceeb hauv qee cov mis zaub mov qis calorie.
3.2 Kev lag luam tshuaj thiab kev kho mob
Methylcellulose siv dav hauv kev lag luam tshuaj, tshwj xeeb tshaj yog hauv kev tsim cov ntsiav tshuaj, ua ib qho khoom siv ntxiv thiab cov khoom sib txuas. Vim nws muaj peev xwm hloov kho viscosity zoo, nws tuaj yeem txhim kho lub zog kho tshuab thiab cov khoom tawg ntawm cov ntsiav tshuaj. Tsis tas li ntawd, methylcellulose kuj tseem siv ua cov khoom tsim kua muag hauv kev kho qhov muag kom kho qhov muag qhuav.
3.3 Kev lag luam tsim kho thiab cov ntaub ntawv
Ntawm cov ntaub ntawv siv hauv kev tsim kho, methylcellulose siv dav hauv cov cement, gypsum, txheej thiab nplaum ua cov khoom ua kom tuab, khaws dej thiab ua zaj duab xis. Vim nws khaws dej zoo, methylcellulose tuaj yeem txhim kho kev ua haujlwm ntawm cov ntaub ntawv siv hauv kev tsim kho thiab tiv thaiv kev tsim cov kab nrib pleb thiab qhov khoob.
3.4 Kev lag luam pleev kom zoo nkauj
Methylcellulose kuj tseem siv ntau hauv kev lag luam pleev kom zoo nkauj ua cov khoom ua kom tuab thiab ruaj khov los pab tsim cov emulsions thiab gels uas kav ntev. Nws tuaj yeem txhim kho qhov kev xav ntawm cov khoom thiab txhim kho cov nyhuv noo noo. Nws yog hypoallergenic thiab mos, thiab tsim nyog rau cov tawv nqaij rhiab heev.
4. Kev sib piv ntawm methylcellulose nrog lwm cov cellulose ethers
Cellulose ethers yog ib tsev neeg loj. Ntxiv rau methylcellulose, kuj tseem muaj ethyl cellulose (EC), hydroxypropyl methylcellulose (HPMC), hydroxyethyl cellulose (HEC) thiab lwm hom. Lawv qhov sib txawv tseem ceeb yog hom thiab qib ntawm kev hloov pauv ntawm cov substituents ntawm cov cellulose molecule, uas txiav txim siab lawv cov solubility, viscosity thiab thaj chaw siv.
Methylcellulose vs Hydroxypropyl Methylcellulose (HPMC): HPMC yog ib qho kev hloov kho dua tshiab ntawm methylcellulose. Ntxiv rau qhov methyl substituent, hydroxypropyl kuj tau qhia, uas ua rau qhov solubility ntawm HPMC ntau yam. HPMC tuaj yeem yaj hauv qhov kub thiab txias dav dua, thiab nws qhov kub thermal gelation siab dua li ntawm methylcellulose. Yog li ntawd, hauv cov ntaub ntawv tsim kho thiab kev lag luam tshuaj, HPMC muaj ntau yam kev siv.
Methylcellulose vs Ethyl Cellulose (EC): Ethyl cellulose tsis yaj hauv dej, tab sis yaj hauv cov kuab tshuaj organic. Nws feem ntau siv rau hauv cov ntaub ntawv membrane uas tso tawm tas mus li rau cov txheej thiab tshuaj. Methyl cellulose yaj hauv dej txias thiab feem ntau yog siv ua tus neeg sawv cev tuab thiab khaws dej. Nws cov cheeb tsam siv txawv ntawm cov ethyl cellulose.
5. Kev loj hlob ntawm cellulose ethers
Nrog rau qhov kev thov nce ntxiv rau cov khoom siv ruaj khov thiab cov tshuaj ntsuab, cov tshuaj cellulose ether, suav nrog methyl cellulose, maj mam dhau los ua ib qho tseem ceeb ntawm cov khoom siv zoo rau ib puag ncig. Nws yog los ntawm cov nroj tsuag ntuj, rov ua dua tshiab, thiab tuaj yeem lwj hauv ib puag ncig. Yav tom ntej, cov chaw siv cellulose ethers yuav raug nthuav dav ntxiv, xws li hauv lub zog tshiab, cov tsev ntsuab thiab biomedicine.
Ua ib hom cellulose ether, methyl cellulose siv dav hauv ntau yam lag luam vim nws cov khoom siv lub cev thiab tshuaj lom neeg tshwj xeeb. Nws tsis tsuas yog muaj kev yaj zoo, tsis muaj tshuaj lom, thiab muaj peev xwm hloov kho viscosity zoo, tab sis kuj ua lub luag haujlwm tseem ceeb hauv zaub mov, tshuaj, kev tsim kho thiab tshuaj pleev ib ce. Yav tom ntej, nrog rau kev thov ntau ntxiv rau cov ntaub ntawv ib puag ncig, kev cia siab ntawm daim ntawv thov ntawm methyl cellulose yuav dav dua.
Lub sijhawm tshaj tawm: Lub Kaum Hli-23-2024