Cellulose ether (CE) yog ib chav kawm ntawm cov khoom siv tau los ntawm kev hloov kho cellulose. Cellulose yog cov khoom tseem ceeb ntawm cov phab ntsa cell ntawm cov nroj tsuag, thiab cellulose ethers yog cov polymers tsim los ntawm etherification ntawm qee pawg hydroxyl (-OH) hauv cellulose. Lawv siv dav hauv ntau qhov chaw xws li cov ntaub ntawv tsim kho, tshuaj, khoom noj, tshuaj pleev ib ce, thiab lwm yam, thiab siv dav hauv ntau yam lag luam vim lawv cov khoom siv lub cev thiab tshuaj lom neeg tshwj xeeb thiab kev hloov pauv tau yooj yim.
1. Kev faib tawm ntawm cellulose ethers
Cov cellulose ethers tuaj yeem muab faib ua ntau hom raws li cov hom substituents hauv cov qauv tshuaj. Kev faib tawm feem ntau yog raws li qhov sib txawv ntawm cov substituents. Cov cellulose ethers feem ntau yog raws li nram no:
Methyl cellulose (MC)
Methyl cellulose yog tsim los ntawm kev hloov qhov hydroxyl ntawm cov cellulose molecule nrog methyl (–CH₃). Nws muaj cov khoom zoo thickening, zaj duab xis-tsim thiab kev sib txuas thiab feem ntau yog siv rau hauv cov ntaub ntawv tsim kho, coatings, tshuaj thiab zaub mov lag luam.
Hydroxypropyl methylcellulose (HPMC)
Hydroxypropyl methylcellulose yog ib qho cellulose ether uas siv ntau, uas siv dav hauv cov ntaub ntawv siv hauv tsev, tshuaj, tshuaj txhua hnub thiab cov zaub mov vim nws cov dej zoo dua thiab kev ruaj khov tshuaj. HPMC yog ib qho cellulose ether nonionic nrog cov khoom ntawm kev khaws cia dej, thickening thiab stability.
Carboxymethyl cellulose (CMC)
Carboxymethyl cellulose yog ib qho anionic cellulose ether uas tsim los ntawm kev qhia cov carboxymethyl (–CH₂COOH) pawg rau hauv cov cellulose molecules. CMC muaj cov dej solubility zoo heev thiab feem ntau siv ua cov khoom siv tuab, stabilizer thiab suspending agent. Nws ua lub luag haujlwm tseem ceeb hauv cov khoom noj, tshuaj thiab tshuaj pleev ib ce.
Ethyl cellulose (EC)
Ethyl cellulose tau los ntawm kev hloov pawg hydroxyl hauv cellulose nrog ethyl (–CH₂CH₃). Nws muaj hydrophobicity zoo thiab feem ntau siv ua tus neeg sawv cev txheej zaj duab xis thiab cov khoom tso tawm tswj hauv kev lag luam tshuaj.
2. Cov khoom siv lub cev thiab tshuaj lom neeg ntawm cellulose ethers
Cov khoom siv lub cev thiab tshuaj ntawm cellulose ethers muaj feem cuam tshuam nrog cov yam xws li hom cellulose ether, hom substituent thiab qib ntawm kev hloov pauv. Nws cov khoom tseem ceeb suav nrog cov hauv qab no:
Kev yaj dej thiab kev yaj
Feem ntau cov cellulose ethers muaj cov dej solubility zoo thiab tuaj yeem yaj rau hauv dej txias lossis dej kub kom tsim tau cov kua colloidal pob tshab. Piv txwv li, HPMC, CMC, thiab lwm yam tuaj yeem yaj sai sai hauv dej kom tsim tau cov kua viscosity siab, uas yog siv dav hauv cov xwm txheej thov nrog cov kev xav tau ua haujlwm xws li thickening, suspension, thiab zaj duab xis tsim.
Cov khoom ua kom tuab thiab ua zaj duab xis
Cellulose ethers muaj cov khoom ua kom tuab zoo heev thiab tuaj yeem ua rau kom cov viscosity ntawm cov kua dej nce ntxiv. Piv txwv li, ntxiv HPMC rau cov ntaub ntawv tsim kho tuaj yeem txhim kho qhov plasticity thiab kev ua haujlwm ntawm cov mortar thiab txhim kho cov khoom tiv thaiv kev sagging. Tib lub sijhawm, cellulose ethers muaj cov khoom ua yeeb yaj kiab zoo thiab tuaj yeem tsim cov yeeb yaj kiab tiv thaiv zoo ib yam ntawm qhov chaw ntawm cov khoom, yog li lawv tau siv dav hauv cov txheej thiab cov tshuaj txheej.
Kev khaws cia dej thiab kev ruaj khov
Cellulose ethers kuj muaj peev xwm khaws dej zoo, tshwj xeeb tshaj yog nyob rau hauv thaj chaw ntawm cov ntaub ntawv tsim kho. Cellulose ethers feem ntau yog siv los txhim kho qhov khaws dej ntawm cov cement mortar, txo qhov tshwm sim ntawm cov kab nrib pleb shrinkage, thiab ntev lub neej kev pabcuam ntawm mortar. Hauv thaj chaw ua zaub mov, CMC kuj tseem siv ua humectant los ncua cov zaub mov qhuav.
Kev ruaj khov tshuaj lom neeg
Cov cellulose ethers qhia tau tias muaj kev ruaj khov zoo hauv cov kua qaub, alkali thiab electrolyte, thiab tuaj yeem tswj lawv cov qauv thiab kev ua haujlwm hauv ntau yam kev ua haujlwm tshuaj lom neeg. Qhov no tso cai rau lawv siv rau hauv ntau yam kev lag luam yam tsis muaj kev cuam tshuam los ntawm lwm cov tshuaj lom neeg.
3. Cov txheej txheem tsim khoom ntawm cellulose ether
Kev tsim cov cellulose ether feem ntau yog npaj los ntawm cov tshuaj etherification ntawm cov cellulose ntuj. Cov kauj ruam yooj yim suav nrog kev kho alkalization ntawm cellulose, etherification reaction, purification, thiab lwm yam.
Kev kho mob alkalization
Ua ntej, cellulose ntuj (xws li paj rwb, ntoo, thiab lwm yam) yog alkalized los hloov cov hydroxyl ib feem hauv cellulose mus rau hauv cov ntsev cawv uas muaj zog heev.
Kev ua haujlwm ntawm Etherification
Cov cellulose tom qab alkalization reacts nrog tus neeg sawv cev etherifying (xws li methyl chloride, propylene oxide, thiab lwm yam) los tsim cov cellulose ether. Nyob ntawm cov xwm txheej ntawm cov tshuaj tiv thaiv, ntau hom cellulose ethers tuaj yeem tau txais.
Kev ntxuav thiab ziab
Cov cellulose ether uas tsim los ntawm cov tshuaj tiv thaiv no raug ntxuav, ntxuav thiab ziab kom tau txais cov hmoov lossis cov khoom me me. Qhov huv thiab cov khoom siv ntawm cov khoom kawg tuaj yeem tswj tau los ntawm kev siv tshuab ua tom qab.
4. Cov teb thov ntawm cellulose ether
Vim yog cov khoom siv lub cev thiab tshuaj lom neeg tshwj xeeb ntawm cellulose ethers, lawv tau siv dav hauv ntau yam lag luam. Cov teb tseem ceeb ntawm daim ntawv thov yog raws li nram no:
Cov ntaub ntawv siv hauv tsev
Hauv kev tsim kho vaj tse, cellulose ethers feem ntau yog siv ua cov khoom ua kom tuab thiab cov neeg sawv cev khaws dej rau cov cement mortar thiab cov khoom lag luam gypsum. Cellulose ethers xws li HPMC thiab MC tuaj yeem txhim kho kev ua haujlwm ntawm cov mortar, txo cov dej poob, thiab yog li txhim kho kev nplaum thiab kev tawg.
Tshuaj kho mob
Hauv kev lag luam tshuaj, cellulose ethers yog siv dav ua cov tshuaj pleev xim rau cov tshuaj, cov nplaum rau cov ntsiav tshuaj, thiab cov ntaub ntawv tswj kev tso tawm. Piv txwv li, HPMC feem ntau yog siv los npaj cov tshuaj zaj duab xis thiab muaj cov nyhuv tswj kev tso tawm zoo.
Khoom noj
CMC feem ntau siv ua cov khoom ua kom tuab, emulsifier, thiab stabilizer hauv kev lag luam zaub mov. Nws siv dav hauv cov dej haus, cov khoom noj mis nyuj, thiab cov khoom ci, thiab tuaj yeem txhim kho cov saj thiab cov khoom noo ntawm cov zaub mov.
Cov tshuaj pleev ib ce thiab cov tshuaj siv niaj hnub
Cellulose ethers yog siv los ua cov khoom ua kom tuab thiab emulsifiers thiab stabilizers hauv cov tshuaj pleev ib ce thiab cov tshuaj txhua hnub, uas tuaj yeem muab cov khoom zoo thiab cov qauv. Piv txwv li, HPMC feem ntau siv rau hauv cov khoom xws li tshuaj txhuam hniav thiab tshuaj zawv plaub hau kom muab lawv cov kev xav viscous thiab cov nyhuv ncua ntev.
Cov txheej txheem
Hauv kev lag luam txheej, cellulose ethers yog siv los ua cov khoom ua kom tuab, cov zaj duab xis, thiab cov neeg sawv cev ncua, uas tuaj yeem txhim kho kev ua tau zoo ntawm cov txheej txheem, txhim kho qib, thiab muab cov xim pleev xim zoo.
5. Kev txhim kho yav tom ntej ntawm cellulose ethers
Nrog rau qhov kev thov kom muaj kev tiv thaiv ib puag ncig ntau ntxiv, cellulose ether, ua ib qho khoom siv rov ua dua tshiab, muaj kev cia siab dav dav. Nws qhov kev puas tsuaj ntawm cov khoom siv hauv lub cev, kev rov ua dua tshiab thiab kev hloov pauv tau yooj yim ua rau nws xav tias yuav siv dav dua hauv cov teb ntawm cov ntaub ntawv ntsuab, cov ntaub ntawv puas tsuaj thiab cov ntaub ntawv ntse yav tom ntej. Tsis tas li ntawd, cellulose ether kuj tseem muaj kev tshawb fawb thiab kev txhim kho ntxiv hauv cov teb muaj nqis ntxiv xws li biomedical engineering thiab cov ntaub ntawv siab heev.
Ua ib yam khoom siv tshuaj lom neeg tseem ceeb, cellulose ether muaj ntau yam txiaj ntsig rau kev siv. Nrog nws cov thickening zoo heev, khaws dej, tsim zaj duab xis thiab ruaj khov tshuaj zoo, nws ua lub luag haujlwm tseem ceeb hauv ntau qhov chaw xws li kev tsim kho, tshuaj, thiab zaub mov. Yav tom ntej, nrog kev nce qib ntawm thev naus laus zis thiab kev txhawb nqa cov tswv yim tiv thaiv ib puag ncig, kev siv cellulose ether yuav dav dua thiab ua rau muaj kev pab txhawb nqa kev txhim kho ntawm ntau yam lag luam.
Lub sijhawm tshaj tawm: Cuaj hlis-24-2024