Cellulose ether yog ib qho khoom siv tseem ceeb hauv kev tsim kho, siv dav hauv kev tsim cov mortar, hmoov putty, txheej thiab lwm yam khoom los txhim kho cov khoom siv lub cev thiab kev ua haujlwm ntawm cov khoom siv. Cov khoom tseem ceeb ntawm cellulose ether suav nrog cov qauv yooj yim cellulose thiab cov khoom hloov pauv uas tau tsim los ntawm kev hloov kho tshuaj, uas ua rau nws muaj kev yaj tshwj xeeb, tuab, khaws dej thiab rheological zog.
1. Cov qauv yooj yim ntawm Cellulose
Cellulose yog ib qho ntawm cov polysaccharides feem ntau nyob rau hauv xwm, feem ntau yog los ntawm cov nroj tsuag fibers. Nws yog lub hauv paus tseem ceeb ntawm cellulose ether thiab txiav txim siab nws cov qauv yooj yim thiab cov khoom. Cellulose molecules yog tsim los ntawm cov glucose units txuas nrog β-1,4-glycosidic bonds los tsim cov qauv saw ntev. Cov qauv linear no muab cellulose lub zog siab thiab qhov hnyav molecular siab, tab sis nws cov solubility hauv dej tsis zoo. Txhawm rau txhim kho cov dej solubility ntawm cellulose thiab hloov kho rau cov kev xav tau ntawm cov ntaub ntawv tsim kho, cellulose yuav tsum tau hloov kho tshuaj.
2. Cov khoom hloov pauv - cov khoom tseem ceeb ntawm kev sib xyaw ua ke
Cov khoom tshwj xeeb ntawm cellulose ether feem ntau yog ua tiav los ntawm cov substituents uas tau qhia los ntawm cov tshuaj etherification ntawm hydroxyl pawg (-OH) ntawm cellulose thiab ether compounds. Cov substituents feem ntau suav nrog methoxy (-OCH₃), ethoxy (-OC₂H₅) thiab hydroxypropyl (-CH₂CHOHCH₃). Kev qhia txog cov substituents no hloov pauv qhov solubility, thickening thiab dej khaws cia ntawm cellulose. Raws li cov substituents sib txawv, cellulose ethers tuaj yeem faib ua methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC) thiab lwm hom.
Methyl cellulose (MC): Methyl cellulose yog tsim los ntawm kev qhia cov methyl substituents (-OCH₃) rau hauv cov hydroxyl pawg hauv cov cellulose molecule. Cov cellulose ether no muaj cov khoom yaj tau zoo hauv dej thiab ua kom tuab thiab siv dav hauv cov mortar qhuav, cov nplaum thiab cov txheej txheem. MC muaj kev khaws dej zoo heev thiab pab txo cov dej poob hauv cov ntaub ntawv tsim kho, ua kom ntseeg tau tias cov mortar thiab putty hmoov lo rau qhov lo thiab lub zog.
Hydroxyethyl cellulose (HEC): Hydroxyethyl cellulose yog tsim los ntawm kev qhia txog hydroxyethyl substituents (-OC₂H₅), uas ua rau nws yaj tau dej ntau dua thiab tiv taus ntsev. HEC feem ntau siv rau hauv cov txheej txheem dej, cov xim latex thiab cov khoom siv hauv tsev. Nws muaj cov khoom ua kom tuab thiab ua zaj duab xis zoo heev thiab tuaj yeem txhim kho kev ua tau zoo ntawm cov ntaub ntawv.
Hydroxypropyl methylcellulose (HPMC): Hydroxypropyl methylcellulose yog tsim los ntawm kev qhia txog hydroxypropyl (-CH₂CHOHCH₃) thiab methyl substituents tib lub sijhawm. Hom cellulose ether no qhia txog kev khaws cia dej zoo heev, lubricity thiab kev ua haujlwm hauv cov ntaub ntawv tsim kho xws li cov av qhuav, cov nplaum pobzeb, thiab cov txheej txheem rwb thaiv tsev phab ntsa sab nraud. HPMC kuj muaj kev tiv thaiv kub zoo thiab kev tiv thaiv te, yog li nws tuaj yeem txhim kho kev ua tau zoo ntawm cov ntaub ntawv tsim kho hauv qab huab cua hnyav.
3. Kev yaj dej thiab ua kom tuab
Qhov dej solubility ntawm cellulose ether nyob ntawm hom thiab qib ntawm kev hloov pauv ntawm cov substituent (piv txwv li, tus lej ntawm cov hydroxyl pawg hloov pauv ntawm txhua chav glucose). Qib tsim nyog ntawm kev hloov pauv ua rau cov cellulose molecules tsim cov tshuaj sib xws hauv dej, muab cov khoom zoo thickening. Hauv cov ntaub ntawv tsim kho, cellulose ethers ua thickeners tuaj yeem ua rau kom viscosity ntawm mortar, tiv thaiv stratification thiab kev sib cais ntawm cov ntaub ntawv, thiab yog li txhim kho kev ua haujlwm tsim kho.
4. Kev khaws dej
Qhov kev khaws dej ntawm cellulose ether yog qhov tseem ceeb rau qhov zoo ntawm cov ntaub ntawv tsim kho. Hauv cov khoom xws li mortar thiab putty hmoov, cellulose ether tuaj yeem tsim cov dej ntom ntom ntawm qhov chaw ntawm cov khoom kom tiv thaiv dej kom tsis txhob evaporate sai dhau, yog li ntawd ntev lub sijhawm qhib thiab kev ua haujlwm ntawm cov khoom. Qhov no ua lub luag haujlwm tseem ceeb hauv kev txhim kho lub zog sib txuas thiab tiv thaiv kev tawg.
5. Rheology thiab kev ua haujlwm ntawm kev tsim kho
Qhov ntxiv ntawm cellulose ether ua rau cov khoom siv hauv tsev zoo dua qub, uas yog, cov dej ntws thiab kev hloov pauv ntawm cov ntaub ntawv nyob rau hauv lub zog sab nraud. Nws tuaj yeem txhim kho qhov khaws dej thiab lubricity ntawm mortar, ua rau kom muaj peev xwm twj thiab yooj yim ntawm kev tsim kho cov ntaub ntawv. Hauv cov txheej txheem kev tsim kho xws li txau, khawb thiab masonry, cellulose ether pab txo qhov tsis kam thiab txhim kho kev ua haujlwm zoo, thaum ua kom cov txheej txheem sib xws yam tsis muaj sagging.
6. Kev sib raug zoo thiab kev tiv thaiv ib puag ncig
Cellulose ether muaj kev sib raug zoo nrog ntau yam khoom siv hauv tsev, suav nrog cement, gypsum, lime, thiab lwm yam. Thaum lub sijhawm tsim kho, nws yuav tsis cuam tshuam tsis zoo nrog lwm cov khoom siv tshuaj lom neeg kom ntseeg tau tias cov khoom ruaj khov. Tsis tas li ntawd, cellulose ether yog cov khoom siv ntsuab thiab zoo rau ib puag ncig, uas feem ntau yog los ntawm cov nroj tsuag ntuj, tsis muaj teeb meem rau ib puag ncig, thiab ua tau raws li cov kev cai tiv thaiv ib puag ncig ntawm cov khoom siv hauv tsev niaj hnub.
7. Lwm cov khoom xyaw hloov kho
Yuav kom txhim kho qhov kev ua tau zoo ntawm cellulose ether ntxiv, lwm cov khoom xyaw hloov kho yuav raug qhia rau hauv kev tsim khoom tiag tiag. Piv txwv li, qee cov chaw tsim khoom yuav txhim kho qhov tsis kam dej thiab tiv taus huab cua ntawm cellulose ether los ntawm kev sib xyaw nrog silicone, paraffin thiab lwm yam tshuaj. Kev ntxiv cov khoom xyaw hloov kho no feem ntau yog kom ua tau raws li cov kev xav tau tshwj xeeb, xws li kev ua kom cov khoom tiv thaiv kev nkag mus thiab kev ruaj khov hauv cov txheej txheem phab ntsa sab nraud lossis cov tshuaj tiv thaiv dej.
Ua ib qho tseem ceeb hauv cov ntaub ntawv tsim kho, cellulose ether muaj ntau yam khoom siv, suav nrog kev ua kom tuab, khaws dej, thiab txhim kho cov khoom rheological. Nws cov khoom tseem ceeb yog cov qauv cellulose yooj yim thiab cov khoom hloov pauv uas tau qhia los ntawm cov tshuaj tiv thaiv etherification. Ntau hom cellulose ethers muaj cov ntawv thov thiab kev ua tau zoo sib txawv hauv cov ntaub ntawv tsim kho vim muaj qhov sib txawv hauv lawv cov khoom hloov pauv. Cellulose ethers tsis tsuas yog txhim kho kev ua tau zoo ntawm cov ntaub ntawv, tab sis kuj txhim kho qhov zoo thiab lub neej ua haujlwm ntawm cov tsev. Yog li ntawd, cellulose ethers muaj kev cia siab dav dav hauv cov ntaub ntawv tsim kho niaj hnub.
Lub sijhawm tshaj tawm: Cuaj hlis-18-2024