Methylcellulose (MC) yog dej-soluble cov polymer compound tau siv nyob rau hauv cov zaub mov, tshuaj, tsim kho txhua hnub, tsim kho thiab lwm yam kev lag luam. Nws cov txheej txheem ntau lawm cuam tshuam nrog ntau cov kauj ruam, feem ntau yog suav nrog cov tshuaj tiv thaiv cellulose, kev hloov pauv, ziab, ziab.
1. Extraction ntawm Cellulose
Cov khoom siv yooj yim ntawm methylcellulose yog cov cellulose ntuj, uas feem ntau yog muab los ntawm ntoo pulp lossis paj rwb. Ua ntej, cov ntoo lossis cov paj rwb yog raug rau kev tshem tawm impurities (xws li lignin, cob, muaj protein, thiab lwm yam) kom tau txais cellulose ntshiab. Cov txheej txheem tshwm sim muaj xws li acid-puag cov qauv thiab enzymatic. Nyob rau hauv lub acid-bas txujcis, ntoo lossis cov paj rwb penp yog kho kom yaj thiab lwm yam impurities, yog li rho tawm cellulose.
2. Kab mob rau ntawm cellulose
Tom ntej no, tshuaj tiv thaiv methylation (kab mob herherification) yog nqa tawm los npaj methylcellose. Cov kauj ruam tseem ceeb ntawm lub heregating cov tshuaj tiv thaiv yog tshuaj sellulose nrog methylating tus neeg sawv cev (methyl iodide, thiab lwm yam) kom tau txais methylcellulose. Cov haujlwm tshwj xeeb yog raws li hauv qab no:
Kev xaiv ntawm kev tawm tsam hnyav: Ncua khaub ncaws (xws li dej, thiab dej cawv lossis dej cawv (xws li sodium hydroxide) qee zaum ntxiv los txhim kho cov tshuaj tiv thaiv kev ua tau zoo.
Cov Tshuaj Tiv Thaiv: Cov tshuaj tiv thaiv yog nqa tawm ntawm qhov kub thiab siab, thiab cov tshuaj tiv thaiv kub ib txwm yog 50-70 ° C. Thaum lub sij hawm cov tshuaj tiv thaiv, methyl chloride reacts nrog hydroxyl (-oh) pawg hauv cellulose los hloov nws mus rau hauv methyl cellulose.
Cov tshuaj tiv thaiv kev tswj hwm: cov tshuaj tiv thaiv methylation yuav tsum tau ua kom muaj kev tswj hwm cov tshuaj tiv thaiv thiab kub. Ntev ntev lub sijhawm kev xav tau lossis kev kub siab dhau yuav ua rau muaj kev cuam tshuam cellulose yuav ua rau tsis tiav ntawm methyl cellulose.
3. Neutralization thiab tu
Tom qab cov tshuaj tiv thaiv tau ua tiav, siv tau methyled reagents thiab catalysts tuaj yeem nyob hauv methyl cellulose khoom, uas yuav tsum tau mob siab thiab ntxuav. Tus txheej txheem nruab nrab feem ntau siv cov tshuaj acidic (xws li acetic acid daws) rau neutralize cov tshuaj alkaline hauv cov tshuaj tiv thaiv. Kev ntxuav cov txheej txheem siv ntau npaum li cas ntawm cov dej lossis dej cawv kom tshem cov kuab tshuaj, cov khoom siv uas tsis raug tshuaj thiab cov khoom lag luam tom qab cov tshuaj tiv thaiv kev coj dawb huv.
4. Kom qhuav thiab crushing
Tom qab ntxuav, lub methylcellulose feem ntau yog nyob rau hauv ib tug muab tshuaj txhuam lossis gel xeev, yog li nws yuav tsum tau qhuav kom tau cov khoom hmoov. Muaj ntau txoj kev kom qhuav, thiab cov siv ntau zaus suav nrog tshuaj txau kom qhuav thiab ziab kom qhuav thiab nqus kom qhuav thiab nqus tsev kom qhuav. Thaum lub sijhawm ua kom qhuav, qhov kub thiab av noo yuav tsum tau nruj me ntsis tswj kom tsis txhob muaj kev cuam tshuam los ntawm kev kub siab lossis kev puas tsuaj rau cov gel khoom.
Tom qab ziab, cov tau txais methylcellulose yuav tsum tau tsoo kom ua tiav qhov uas yuav tsum tau loj. Kev sib tsoo txheej txheem yog feem ntau ua tiav los ntawm huab cua dav hlau milling lossis tshuab milling. Los ntawm kev tswj cov particle loj li cas, tus lej xaus thiab viscosity yam ntxwv ntawm methylcellulose tuaj yeem hloov kho.
5. Kev tshuaj xyuas thiab ntim ntawm cov khoom kawg
Tom qab crushing, lub methylcellulose yuav tsum tau yauv tswj nruj kom ntseeg tau tias nws ua tau raws li cov kev qhia txuj ci. Cov khoom ntsuas kev tshuaj xyuas suav nrog:
Cov ntsiab lus noo: Dhau mot ya raws cov ntsiab lus ntawm methylcellulose yuav cuam tshuam nws cov ruaj khov thiab cia.
Particle loj faib: Qhov loj me thiab faib cov khoom yuav cuam tshuam rau solubility ntawm methylcelulose.
Qib ntawm methylation: kev kawm methylation yog qhov taw qhia tseem ceeb rau kev ntsuas methylcellulose, cuam tshuam rau nws solubility thiab thov ua tiav.
Solubility thiab Viscosity: lub solubility thiab viscosity ntawm methylcellulose yog qhov tsis tseem ceeb hauv nws daim ntawv thov, tshwj xeeb yog nyob hauv thaj teb khoom noj thiab tshuaj.
Tom qab dhau mus soj ntsuam, cov khoom yuav ntim tau raws li cov hnab yas, feem ntau yog cov hnab yas, thiab cim nrog cov ntaub ntawv tshwj xeeb, cov lus qhia tshwj xeeb, hnub ua haujlwm ntau lawm.
6. Kev tiv thaiv ib puag ncig thiab kev nyab xeeb
Thaum lub sijhawm ua tiav ntawm methyl cellulose, tsim nyog tiv thaiv ib puag ncig kev tiv thaiv yuav tsum tau noj, tshwj xeeb yog rau cov txheej txheem kev tshuaj tiv thaiv. Tom qab cov tshuaj tiv thaiv, pov tseg kua thiab roj av yuav tsum tau kho kom tsis txhob muaj kuab paug ib puag ncig. Ib qho ntxiv, tshuaj lom neeg cov tshuaj reagents hauv cov txheej txheem ntau lawm yuav tsum tau nruj me ntsis ua raws li cov txheej txheem kev nyab xeeb kom ntseeg tau tias cov neeg ua haujlwm kev nyab xeeb.
Cov txheej txheem ntau lawm ntawm methyl cellulose feem ntau yog suav nrog cellulose tawm, methylation, ntxuav thiab kev ziab, kom qhuav thiab tawg. Txhua qhov txuas muaj qhov cuam tshuam tseem ceeb rau qhov zoo ntawm cov khoom kawg, yog li kev tswj hwm thiab saib xyuas hauv cov txheej txheem ntau lawm yog qhov tseem ceeb heev. Los ntawm cov txheej txheem no cov kauj ruam, methyl cellulose uas ua tau raws li cov ntawv thov sib txawv tuaj yeem ua tau.
Lub Sijhawm Post: Feb-19-2025