Qhov sib txawv ntawm kev yaj sai thiab qeeb ntawm HPMC

Hauv kev siv ntawmHydroxypropyl methyl cellulose HPMC, peb feem ntau pom tias nws yog feem ntau muab faib ua ob hom: tam sim ntawd thiab qeeb qeeb yaj. Cia peb nkag siab qhov txawv ntawm kev yaj sai thiab qeeb qeeb yaj ntawm hydroxypropyl methyl cellulose.

HPMC tam sim ntawd yog hais txog kev siv tus neeg sawv cev sib txuas rau kev kho qhov chaw hauv cov txheej txheem ntau lawm, yog li HPMC tuaj yeem tawg sai sai hauv dej txias, tab sis tsis yog qhov kev daws teeb meem tiag tiag, los ntawm kev sib xyaw ua ke, viscosity maj mam nce, uas yog, yaj;

HPMC uas yaj qeeb qeeb kuj tseem hu ua cov khoom kub yaj. Thaum ntsib dej txias, nws tuaj yeem tawg sai sai hauv dej kub. Los ntawm kev do kom sib npaug, qhov kub ntawm cov tshuaj yuav poob rau qee qhov kub. (Qhov kub ntawm peb cov gel yog li 60 ° C), qhov viscosity yuav tshwm sim qeeb qeeb kom txog thaum cov gel pob tshab thiab nplaum tau tsim.

Nov yog qhov sib txawv ntawm kev daws teeb meem tam sim ntawd thiab kev daws teeb meem qeeb. Yog tias koj muaj lus nug txog qhov kev paub no, koj tuaj yeem sab laj nrog peb.

Hydroxypropyl methyl celluloseHPMCncua kev ua kom cov cement noo

Ntxiv hydroxypropyl methyl cellulose rau hauv cement ua rau nws qeeb qeeb rau kev nqus dej. Yog li koj paub dab tsi txog nws ua haujlwm li cas? Cia peb saib hydroxypropyl methyl cellulose los ncua kev nqus dej ntawm cement. Lub hauv paus ntsiab lus.

1. Kev xav txog kev tsis sib haum xeeb ntawm Ion

Peb xav tias hydroxypropyl methyl cellulose yuav ua rau kom cov kua dej ntawm cov qhov hws nce ntxiv, ua rau cov ionic txav tsis tau, thiab ncua qhov hydration ntawm cement. Txawm li cas los xij, cov cellulose ethers uas muaj viscosity qis dua hauv qhov kev sim no muaj peev xwm ua kom qeeb cov cement hydration. Yog li ntawd, qhov kev xav no tsis raug. Pourchez et al. kuj tsis ntseeg qhov kev xav no. Qhov tseeb, lub sijhawm ntawm ion migration lossis migration luv heev, zoo li tsis txawv ntawm qhov kev ncua ntawm cement hydration.

2. Kev puas tsuaj ntawm alkaline

Cov polysaccharides yooj yim lwj hauv qab alkaline kom tsim cov hydroxyl carboxylic acids uas ncua kev hydration ntawm cement. Yog li ntawd, qhov qeeb hydration ntawm hydroxypropyl methyl cellulose tej zaum yuav yog vim nws qhov kev puas tsuaj hauv alkaline cement slurries los tsim cov hydroxycarboxylic acids. Txawm li cas los xij, Pourchez et al. pom tias cellulose ethers ruaj khov heev hauv qab alkaline, lwj me ntsis xwb, thiab cov khoom puas tsuaj tsis muaj feem cuam tshuam rau qhov qeeb ntawm cement hydration.

3, qhov adsorption

Kev nqus tau tuaj yeem yog hydroxypropyl methyl cellulose thaiv cement hydration qhov laj thawj tiag tiag yog tias ntau cov organic additives yuav raug adsorbed rau ntawm cov cement particles thiab hydration khoom, tiv thaiv kev yaj ntawm cov cement particles thiab crystallization ntawm hydration khoom, yog li ntawd ncua qhov hydration thiab condensation ntawm cement. Pourchez et al. pom tias cellulose ethers yooj yim adsorbed rau ntawm qhov chaw ntawm hydration khoom xws li calcium hydroxide, CSH gel thiab calcium aluminate hydrate, tab sis tsis yooj yim adsorbed los ntawm ettringite thiab unhydrated theem. Ntxiv mus, nyob rau hauv cov ntaub ntawv ntawm cellulose ether, lub peev xwm adsorption ntawm HEC yog muaj zog dua li ntawm o MC. Qhov qis dua cov ntsiab lus ntawm hydroxyethyl hauv HEC lossis hydroxypropyl hauvHPMC, qhov muaj zog dua qhov muaj peev xwm adsorption: raws li rau cov khoom hydration, qhov muaj peev xwm adsorption ntawm calcium hydroxide muaj zog dua li ntawm CSH. Kev tshuaj xyuas ntxiv kuj qhia tau tias qhov muaj peev xwm adsorption ntawm cov khoom hydration thiab cellulose ether muaj feem cuam tshuam nrog kev ncua ntawm cement hydration: qhov muaj zog dua qhov adsorption, qhov pom tseeb dua qhov ncua, tab sis ettringite adsorption ntawm cellulose ether tsis muaj zog, tab sis nws txoj kev tsim, tab sis qhov no qeeb heev. cellulose ether ntawm tricalcium silicate thiab nws cov khoom hydration muaj qhov adsorption muaj zog, nws pom tseeb tias ncua cov txheej txheem hydration ntawm silicate theem, qhov nyiaj adsorption ntawm ettringite yog qis heev, tab sis kev ncua ettringite tsim yog pom tseeb, vim yog kev ncua ettringite tsim yog cuam tshuam los ntawm Ca 2 + sib npaug hauv cov tshuaj, nws yog kev txuas ntxiv ntawm cellulose ether. Lig silicate hydration txuas ntxiv mus.

Cov no yog hydroxypropyl methyl cellulose qeeb cement hydration txoj cai. Peb vam tias qhov kev paub no yuav ua rau txhua tus nkag siab txog cov khoom ua haujlwm li cas thiab siv nws zoo dua.