Cellulose ether yog ib qho tseem ceeb hauv tsev cov khoom siv ntxiv, dav siv hauv tsev mortar, putty hmoov, txheej thiab lwm yam khoom los txhim kho lub cev thiab kev tsim kho ntawm cov khoom. Cov khoom tseem ceeb ntawm cellulose ether suav nrog cov qauv cellulose hauv paus thiab cov khoom hloov pauv tau qhia los ntawm kev hloov kho tshuaj, uas muab nws qhov tshwj xeeb solubility, thickening, dej tuav thiab rheological zog.
1. Cellulose yooj yim qauv
Cellulose yog ib qho ntawm feem ntau polysaccharides nyob rau hauv cov xwm, feem ntau muab tau los ntawm cov nroj tsuag fibers. Nws yog lub hauv paus tseem ceeb ntawm cellulose ether thiab txiav txim siab nws cov qauv thiab cov khoom. Cellulose molecules yog tsim los ntawm qabzib units txuas nrog β-1,4-glycosidic bonds los tsim ib txoj hlua ntev. Cov qauv linear no muab cellulose siab zog thiab siab molecular hnyav, tab sis nws solubility hauv dej tsis zoo. Txhawm rau txhim kho cov dej solubility ntawm cellulose thiab hloov mus rau cov kev xav tau ntawm cov khoom siv hauv tsev, cellulose yuav tsum tau hloov kho tshuaj.
2. Cov khoom hloov pauv-cov khoom tseem ceeb ntawm cov tshuaj tiv thaiv etherification
Cov khoom tshwj xeeb ntawm cellulose ether yog ua tiav los ntawm cov khoom siv hloov pauv tau qhia los ntawm cov tshuaj tiv thaiv etherification ntawm pawg hydroxyl (-OH) ntawm cellulose thiab ether compounds. Cov khoom siv feem ntau suav nrog methoxy (-OCH₃), ethoxy (-OC₂H₅) thiab hydroxypropyl (-CH₂CHOHCH₃). Kev taw qhia ntawm cov khoom hloov pauv hloov cov solubility, thickening thiab dej tuav ntawm cellulose. Raws li cov khoom siv sib txawv, cov cellulose ethers tuaj yeem muab faib ua methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC) thiab lwm yam.
Methyl cellulose (MC): Methyl cellulose yog tsim los ntawm kev qhia methyl substituents (-OCH₃) rau hauv pawg hydroxyl hauv cellulose molecule. Cov cellulose ether no muaj cov dej zoo solubility thiab thickening zog thiab yog dav siv nyob rau hauv qhuav mortar, adhesives thiab coatings. MC muaj cov dej tuav zoo heev thiab pab txo cov dej poob hauv cov khoom siv hauv tsev, kom ntseeg tau qhov adhesion thiab lub zog ntawm mortar thiab putty hmoov.
Hydroxyethyl cellulose (HEC): Hydroxyethyl cellulose yog tsim los ntawm kev qhia hydroxyethyl substituents (-OC₂H₅), uas ua rau nws ntau dej-soluble thiab ntsev-resistant. HEC feem ntau yog siv rau hauv cov dej-raws li txheej, latex xim thiab lub tsev additives. Nws muaj cov thickening zoo heev thiab zaj duab xis-tsim cov khoom thiab tuaj yeem txhim kho kev tsim kho ntawm cov ntaub ntawv zoo.
Hydroxypropyl methylcellulose (HPMC): Hydroxypropyl methylcellulose yog tsim los ntawm kev qhia ib txhij ntawm hydroxypropyl (-CH₂CHOHCH₃) thiab methyl substituents. Hom cellulose ether no nthuav tawm cov dej tuav tau zoo, lubricity thiab kev ua haujlwm hauv cov khoom siv hauv tsev xws li cov tshuaj khib nyiab qhuav, cov nplais nplaum nplaum, thiab cov kab hluav taws xob sab nrauv. HPMC kuj muaj qhov kub thiab txias tsis kam, yog li nws tuaj yeem txhim kho kev ua haujlwm ntawm cov khoom siv hauv tsev nyob rau hauv huab cua huab cua.
3. Dej solubility thiab thickening
Cov dej solubility ntawm cellulose ether nyob ntawm seb hom thiab qib ntawm kev hloov pauv ntawm qhov hloov pauv (piv txwv li, tus naj npawb ntawm hydroxyl pawg hloov ntawm txhua chav tsev piam thaj). Qhov tsim nyog ntawm kev hloov pauv ua rau cov cellulose molecules tsim ib qho kev daws teeb meem hauv dej, muab cov khoom zoo thickening zog. Hauv cov khoom siv hauv tsev, cellulose ethers li thickeners tuaj yeem ua kom cov viscosity ntawm cov tshuaj khib, tiv thaiv kev sib cais thiab kev sib cais ntawm cov ntaub ntawv, thiab yog li txhim kho kev tsim kho.
4. Kev tuav dej
Kev tuav dej ntawm cellulose ether yog qhov tseem ceeb rau qhov zoo ntawm cov khoom siv hauv tsev. Hauv cov khoom xws li tshuaj khib thiab ua kom muaj hmoov, cellulose ether tuaj yeem tsim cov khoom siv tsis ntev dhau los, yog li txuas tau lub sijhawm qhib thiab ua haujlwm ntawm cov khoom. Qhov no ua lub luag haujlwm tseem ceeb hauv kev txhim kho kev sib txuas ntawm lub zog thiab tiv thaiv kev tawg.
5. Rheology thiab kev tsim kho kev ua haujlwm
Qhov sib ntxiv ntawm cellulose ether ho txhim kho rheological zog ntawm lub tsev cov ntaub ntawv, uas yog, ntws thiab deformation tus cwj pwm ntawm cov ntaub ntawv nyob rau hauv sab nraud quab yuam. Nws tuaj yeem txhim kho cov dej tuav thiab lubricity ntawm mortar, ua kom lub twj tso kua mis thiab yooj yim ntawm kev tsim cov ntaub ntawv. Nyob rau hauv cov txheej txheem tsim kho xws li tshuaj tsuag, scraping thiab masonry, cellulose ether pab txo qhov tsis kam thiab txhim kho kev ua haujlwm, thaum ua kom cov txheej txheej tsis sagging.
6. Compatibility thiab kev tiv thaiv ib puag ncig
Cellulose ether muaj kev sib raug zoo nrog ntau yam khoom siv hauv tsev, nrog rau cov cement, gypsum, txiv qaub, thiab lwm yam. Thaum lub sij hawm tsim kho, nws yuav tsis hnov mob rau lwm yam tshuaj los xyuas kom meej cov khoom ruaj khov. Tsis tas li ntawd, cellulose ether yog ib qho ntsuab thiab ib puag ncig tus phooj ywg additive, uas feem ntau yog muab los ntawm cov nroj tsuag ntuj fibers, tsis muaj teeb meem rau ib puag ncig, thiab ua tau raws li kev tiv thaiv ib puag ncig ntawm cov khoom siv niaj hnub no.
7. Lwm cov khoom xyaw hloov kho
Txhawm rau txhawm rau txhim kho kev ua haujlwm ntawm cellulose ether, lwm cov khoom xyaw hloov kho yuav raug qhia hauv kev tsim khoom tiag. Piv txwv li, qee cov tuam txhab lag luam yuav txhim kho cov dej tsis kam thiab huab cua tsis kam ntawm cellulose ether los ntawm kev sib xyaw nrog silicone, paraffin thiab lwm yam khoom. Qhov sib ntxiv ntawm cov khoom xyaw hloov kho no feem ntau yog ua kom tau raws li cov kev xav tau tshwj xeeb, xws li nce cov khoom tiv thaiv permeability thiab durability nyob rau hauv sab nrauv phab ntsa coatings los yog waterproof mortars.
Raws li ib qho tseem ceeb ntawm cov khoom siv hauv tsev, cellulose ether muaj cov khoom siv ntau yam, nrog rau cov thickening, dej tuav, thiab txhim kho rheological zog. Nws cov khoom tseem ceeb yog cov qauv hauv paus cellulose thiab cov khoom hloov pauv tau qhia los ntawm cov tshuaj tiv thaiv etherification. Ntau hom cellulose ethers muaj ntau daim ntawv thov thiab kev ua yeeb yam hauv cov khoom siv hauv tsev vim qhov sib txawv ntawm lawv cov khoom siv. Cellulose ethers tuaj yeem tsis tsuas yog txhim kho kev tsim kho ntawm cov ntaub ntawv, tab sis kuj txhim kho tag nrho cov khoom zoo thiab kev pabcuam lub neej ntawm cov tsev. Yog li ntawd, cellulose ethers muaj dav daim ntawv thov kev cia siab nyob rau hauv niaj hnub tsev cov ntaub ntawv.
Lub sij hawm xa tuaj: Sep-18-2024