Hydroxypropyl methylcellulose (HPMC) yog ntau yam cellulose ether dav siv nyob rau hauv kev tsim kho kev lag luam, tshwj xeeb tshaj yog nyob rau hauv qhuav mix mortar formulations. Nws cov khoom tshwj xeeb txhim kho kev ua tau zoo thiab tuav cov mortars, ua rau muaj txiaj ntsig zoo.
Chemical Structure thiab Synthesis
HPMC yog muab los ntawm cellulose, ib tug natural polymer pom nyob rau hauv lub cell phab ntsa ntawm cov nroj tsuag. Nws yog synthesized los ntawm etherification ntawm cellulose nrog methyl chloride thiab propylene oxide. Cov txheej txheem no hloov qee pawg hydroxyl hauv cellulose molecule nrog methoxy (-OCH₃) thiab hydroxypropyl (-OCH₂CH(OH)CH₃) pawg. Qib ntawm kev hloov pauv thiab qhov piv ntawm methoxy rau hydroxypropyl pawg txiav txim siab cov khoom tshwj xeeb ntawm HPMC, xws li solubility, viscosity, thiab thermal gelation.
Cov khoom ntawm HPMC hauv Dry-Mix Mortar
1. Kev tuav dej
HPMC muaj txiaj ntsig zoo hauv kev khaws cov dej hauv cov tshuaj khib nyiab. Cov cuab yeej tuav dej no yog qhov tseem ceeb vim nws ua kom muaj dej kom zoo ntawm cov cement, txhim kho cov txheej txheem kho. Kev txhim kho dej khaws cia ua rau muaj kev ua haujlwm zoo dua thiab lub sijhawm qhib ntev dua, txo qhov kev pheej hmoo ntawm kev ziab ntxov ntxov, uas tuaj yeem ua rau shrinkage thiab tawg. Tsis tas li ntawd, nws ua kom muaj dej zoo sib xws rau cov cement hydration, txhim kho cov khoom siv dag zog thiab lub zog ntawm cov mortar.
2. Kev Kho Mob Rheology
HPMC tau hloov kho qhov rheology ntawm cov tshuaj khib nyiab qhuav. Nws ua raws li ib tug thickener, ua rau lub viscosity ntawm lub mortar mix. Cov cuab yeej no yog qhov tseem ceeb rau kev tswj cov dej ntws thiab kev sib kis ntawm cov tshuaj khib nyiab, ua kom yooj yim rau kev thov rau ntawm qhov chaw ntsug yam tsis muaj sagging. Nws kuj tseem pab kom ua tiav cov txheej txheem du thiab sib xws thaum lub sijhawm thov, kom ntseeg tau zoo dua adhesion thiab cohesion. Kev hloov kho Rheological los ntawm HPMC txhim kho kev tuav tag nrho thiab cov yam ntxwv ntawm cov tshuaj khib nyiab.
3. Kev Txhim Kho Adhesion
HPMC txhim kho cov khoom nplaum ntawm cov khoom sib xyaw qhuav. Nws txhim kho kev sib raug zoo ntawm cov mortar thiab ntau yam substrates xws li cib, pob zeb, thiab vuas. Qhov no yog qhov tseem ceeb tshwj xeeb hauv cov ntawv thov xws li cov nplais nplaum thiab cov txheej txheem thermal rwb thaiv tsev sab nraud. Kev txhim kho adhesion txo qhov kev pheej hmoo ntawm delamination thiab ua kom lub sij hawm ntev ntawm cov ntaub ntawv mortar.
4. Kev ua haujlwm tau zoo thiab sib xws
Ib qho ntawm cov txiaj ntsig tseem ceeb ntawm HPMC yog kev txhim kho hauv kev ua haujlwm thiab sib xws ntawm cov tshuaj khib nyiab qhuav. Nws tso cai rau kev sib xyaw yooj yim thiab daim ntawv thov du, muab cov creamy zoo nkauj uas yooj yim rau kev sib kis thiab cov duab. Kev txhim kho kev ua haujlwm tau zoo txo qhov kev siv dag zog uas yuav tsum tau ua thaum thov, ua rau cov txheej txheem ua haujlwm tau zoo dua thiab siv zog tsawg dua. Nws kuj ua kom muaj kev sib faib ntau dua ntawm cov tshuaj khib nyiab, ua rau kev ua tiav zoo dua.
5. Thermal Gelation
HPMC nthuav tawm cov khoom siv thermal gelation, txhais tau tias nws tsim cov gel thaum rhuab. Cov cuab yeej no muaj txiaj ntsig zoo hauv cov ntawv thov uas yuav tsum tau ua kom sov. Thaum lub sij hawm daim ntawv thov ntawm mortar, lub tshav kub generated yuav ua rau ib ntus nce nyob rau hauv viscosity, uas yuav pab tau nyob rau hauv kev tswj cov duab thiab stability ntawm cov ntaub ntawv mortar. Thaum qhov kub thiab txias poob, cov gel rov qab mus rau nws lub xeev qub, tso cai rau kev ua haujlwm txuas ntxiv.
6. Cua nkag
HPMC tuaj yeem ua kom paub thiab ua kom ruaj khov ntawm cov cua tshuab ua npuas hauv cov tshuaj khib nyiab. Cov cua nkag no txhim kho qhov khov-thaw tsis kam ntawm cov tshuaj khib nyiab los ntawm kev muab qhov chaw rau cov dej khov ua kom nthuav dav, txo qis hauv siab thiab tiv thaiv kev puas tsuaj. Tsis tas li ntawd, cov cua nkag tau zoo txhim kho cov haujlwm ua haujlwm thiab cov twj tso kua mis ntawm cov mortar, ua kom yooj yim rau kev siv ntau yam.
7. Compatibility nrog lwm yam additives
HPMC yog sib xws nrog ntau yam ntawm lwm yam additives uas feem ntau siv nyob rau hauv qhuav-mix mortars, xws li superplasticizers, retarders, thiab accelerators. Qhov kev sib raug zoo no tso cai rau kev tsim cov mortar sib xyaw kom tau raws li cov kev xav tau tshwj xeeb. Piv txwv li, HPMC tuaj yeem ua haujlwm sib koom ua ke nrog superplasticizers txhawm rau txhim kho cov dej ntws zoo thaum tswj xyuas qhov xav tau viscosity.
8. Zaj duab xis tsim
HPMC tsim ib zaj duab xis nyias, hloov tau yooj yim thaum ziab, uas ua rau cov khoom ntawm cov tshuaj khib nyiab. Qhov kev tsim zaj duab xis no pab tswj cov dej evaporation thiab txhim kho lub zog saum npoo thiab durability ntawm mortar. Nws kuj tseem muab cov txheej txheem tiv thaiv uas tuaj yeem txhim kho huab cua tiv thaiv thiab kev puas tsuaj ntawm cov tshuaj khib nyiab.
9. Kev tiv thaiv ib puag ncig
HPMC muab kev tiv thaiv rau ntau yam ib puag ncig, nrog rau cov dej noo, qhov kub thiab txias, thiab raug tshuaj lom neeg. Qhov kev tiv thaiv no yog qhov tseem ceeb rau kev ua haujlwm ntev thiab kev ua haujlwm ntev ntawm cov khoom sib xyaw qhuav, tshwj xeeb tshaj yog nyob rau hauv hnyav lossis hloov pauv ib puag ncig. Nws pab tswj cov kev ua tau zoo thiab cov tsos ntawm cov mortar overtime, txo qhov kev xav tau ntawm kev tu lossis kho ntau zaus.
10. Kev Siv Tshuaj thiab Daim Ntawv Thov
Qhov ntau npaum ntawm HPMC nyob rau hauv qhuav-mix mortars feem ntau yog li ntawm 0.1% mus rau 0.5% los ntawm qhov hnyav ntawm qhov sib tov qhuav. Cov koob tshuaj tshwj xeeb yog nyob ntawm cov khoom xav tau thiab hom kev thov. Piv txwv li, ntau npaum li cas yuav siv tau nyob rau hauv cov pobzeb nplaum los txhim kho adhesion thiab workability, thaum qis npaum li cas tej zaum yuav txaus rau lub hom phiaj mortars. Kev koom ua ke ntawm HPMC hauv kev sib xyaw qhuav yog ncaj qha, thiab nws tuaj yeem yooj yim tawg thaum lub sijhawm sib tov.
HPMC yog ib qho tseem ceeb ntawm cov khoom sib xyaw qhuav vim nws cov khoom siv ntau yam. Nws muaj peev xwm khaws dej, hloov kho rheology, txhim kho adhesion, txhim khu kev ua haujlwm, thiab muab kev tiv thaiv ib puag ncig ua rau nws muaj txiaj ntsig zoo hauv ntau yam kev tsim kho. Los ntawm kev nkag siab thiab siv cov cuab yeej tseem ceeb ntawm HPMC, cov neeg tsim khoom tuaj yeem tsim cov khoom ua kom qhuav-sib xyaw uas ua tau raws li qhov xav tau ntawm kev tsim kho niaj hnub no.
Post lub sij hawm: Jun-14-2024