Methylcellulose (MC) thiab carboxymethylcellulose (CMC) yog ob hom cellulose derivatives uas siv dav hauv cov khoom noj, tshuaj, kev tsim kho, kev lag luam tshuaj lom neeg thiab lwm yam. Txawm hais tias lawv txhua tus tau hloov kho los ntawm cov cellulose ntuj, tab sis muaj qhov sib txawv tseem ceeb hauv cov qauv tshuaj, cov khoom siv lub cev thiab tshuaj, thiab kev siv.
1. Cov qauv tshuaj lom neeg thiab cov txheej txheem npaj
Methylcellulose yog tsim los ntawm kev cuam tshuam cellulose nrog methyl chloride (lossis methanol) nyob rau hauv alkaline mob. Thaum lub sijhawm no, ib feem ntawm cov hydroxyl pawg (-OH) hauv cov cellulose molecules raug hloov los ntawm methoxy pawg (-OCH₃) los tsim methylcellulose. Qib ntawm kev hloov pauv (DS, tus lej ntawm cov substituents ib chav glucose) ntawm methylcellulose txiav txim siab nws cov khoom siv lub cev thiab tshuaj, xws li solubility thiab viscosity.
Carboxymethylcellulose yog tsim los ntawm kev sib xyaw cellulose nrog chloroacetic acid nyob rau hauv alkaline mob, thiab cov hydroxyl pawg yog hloov los ntawm carboxymethyl (-CH₂COOH). Qhov degree ntawm kev hloov pauv thiab degree ntawm polymerization (DP) ntawm CMC cuam tshuam rau nws cov solubility thiab viscosity hauv dej. CMC feem ntau muaj nyob rau hauv daim ntawv ntawm sodium ntsev, hu ua sodium carboxymethylcellulose (NaCMC).
2. Cov khoom siv lub cev thiab tshuaj lom neeg
Kev yaj tau: Methylcellulose yaj hauv dej txias, tab sis poob kev yaj thiab tsim cov gel hauv dej kub. Qhov kev hloov pauv thermal no ua rau nws siv tau ua tus neeg sawv cev thickener thiab gelling hauv kev ua zaub mov. CMC yaj tau hauv dej txias thiab dej kub, tab sis qhov viscosity ntawm nws cov tshuaj txo qis thaum qhov kub nce.
Viscosity: Qhov viscosity ntawm ob qho tib si yog cuam tshuam los ntawm qib ntawm kev hloov pauv thiab kev sib xyaw ua ke ntawm cov kua. Qhov viscosity ntawm MC ua ntej nce thiab tom qab ntawd txo qis thaum qhov kub nce, thaum qhov viscosity ntawm CMC txo qis thaum qhov kub nce. Qhov no muab lawv tus kheej qhov zoo hauv kev siv hauv kev lag luam sib txawv.
Kev ruaj khov ntawm pH: CMC tseem ruaj khov rau ntau qhov pH, tshwj xeeb tshaj yog nyob rau hauv cov xwm txheej alkaline, uas ua rau nws nrov heev ua tus stabilizer thiab thickener hauv cov khoom noj thiab tshuaj. MC ruaj khov nyob rau hauv cov xwm txheej nruab nrab thiab me ntsis alkaline, tab sis yuav lwj hauv cov kua qaub lossis alkalis muaj zog.
3. Cov cheeb tsam thov
Kev Lag Luam Khoom Noj: Methylcellulose feem ntau siv rau hauv cov khoom noj ua cov khoom ua kom tuab, emulsifier thiab stabilizer. Piv txwv li, nws tuaj yeem ua raws li qhov saj thiab cov qauv ntawm cov rog thaum tsim cov khoom noj uas muaj roj tsawg. Carboxymethylcellulose feem ntau siv rau hauv cov dej haus, cov khoom ci thiab cov khoom noj mis nyuj ua cov khoom ua kom tuab thiab stabilizer kom tiv thaiv kev sib cais dej thiab txhim kho qhov saj.
Kev lag luam tshuaj: Methylcellulose siv rau hauv kev npaj cov ntsiav tshuaj ua tus khi thiab disintegrant, thiab kuj yog cov roj nplua nyeem thiab tus neeg sawv cev tiv thaiv, xws li hauv cov tshuaj qhov muag ophthalmic ua cov kua muag hloov. CMC yog siv dav hauv tshuaj vim nws cov biocompatibility zoo, xws li kev npaj cov tshuaj tso tawm tas mus li thiab cov nplaum hauv cov tshuaj qhov muag.
Kev tsim kho thiab kev lag luam tshuaj lom neeg: MC siv dav hauv cov ntaub ntawv tsim kho ua cov khoom ua kom tuab, tus neeg sawv cev khaws dej thiab nplaum rau cement thiab gypsum. Nws tuaj yeem txhim kho kev ua haujlwm ntawm kev tsim kho thiab qhov zoo ntawm cov ntaub ntawv. CMC feem ntau siv rau hauv kev kho av nkos hauv kev khawb av roj, slurry hauv kev luam ntawv thiab zas xim, txheej ntawv saum npoo, thiab lwm yam.
4. Kev nyab xeeb thiab kev tiv thaiv ib puag ncig
Ob qho tib si suav tias muaj kev nyab xeeb rau kev siv hauv cov khoom noj thiab tshuaj, tab sis lawv cov peev txheej thiab cov txheej txheem tsim khoom yuav muaj kev cuam tshuam sib txawv rau ib puag ncig. Cov khoom siv raw ntawm MC thiab CMC yog los ntawm cov cellulose ntuj thiab yog biodegradable, yog li lawv ua tau zoo hauv kev phooj ywg ib puag ncig. Txawm li cas los xij, lawv cov txheej txheem tsim khoom yuav suav nrog cov tshuaj yaj thiab cov tshuaj reagents, uas yuav muaj qee qhov cuam tshuam rau ib puag ncig.
5. Tus nqi thiab kev xav tau ntawm kev ua lag luam
Vim muaj ntau yam txheej txheem tsim khoom sib txawv, tus nqi tsim khoom ntawm methylcellulose feem ntau siab dua, yog li nws tus nqi ua lag luam kuj siab dua li carboxymethylcellulose. CMC feem ntau muaj kev thov ua lag luam ntau dua vim nws daim ntawv thov dav dua thiab tus nqi tsim khoom qis dua.
Txawm hais tias methylcellulose thiab carboxymethylcellulose yog ob qho tib si derivatives ntawm cellulose, lawv muaj qhov sib txawv tseem ceeb hauv cov qauv, cov khoom, daim ntawv thov thiab kev thov ua lag luam. Methylcellulose feem ntau yog siv rau hauv cov teb ntawm cov khoom noj, tshuaj thiab cov ntaub ntawv tsim kho vim nws qhov tshwj xeeb thermal reversibility thiab kev tswj hwm viscosity siab. Carboxymethyl cellulose tau siv dav hauv cov khoom noj, tshuaj, petrochemical, textile thiab lwm yam lag luam vim nws cov solubility zoo heev, viscosity hloov kho thiab dav pH adaptability. Kev xaiv ntawm cellulose derivative nyob ntawm qhov xwm txheej thov tshwj xeeb thiab cov kev xav tau.
Lub sijhawm tshaj tawm: Lub Yim Hli-20-2024