Cov qauv ntawm polycarboxylic superplasticizer yog dab tsi?

Tus neeg saib xyuas dej txo qis yog hais txog cov khoom siv ntxiv uas tuaj yeem txo cov dej sib tov thaum ua haujlwm thiab cov cement ntau npaum li cas ntawm cov pob zeb tsis hloov, yog li txhim kho cov pob zeb ua kom muaj zog, lossis txuag cov cement ntau npaum thaum tswj kev ua haujlwm thiab lub zog. Raws li lawv cov dej-txo thiab lub zog-txhim kho muaj peev xwm, cov dej-txo cov neeg ua haujlwm tuaj yeem muab faib ua cov dej-txo cov neeg ua haujlwm zoo tib yam (tseem hu ua plasticizers) thiab cov dej-txo cov neeg ua haujlwm siab (tseem hu ua superplasticizers), ntxiv muab faib ua thawj zaug. -chav kawm thiab cov khoom tsim nyog.

Txoj kev loj hlob ntawm cov dej-txo cov neeg sawv cev tuaj yeem muab faib ua peb theem: thawj tiam ntawm cov dej-txo cov neeg sawv cev los ntawm ntoo calcium; thib ob tiam ntawm high-efficiency dej-txo cov neeg sawv cev los ntawm naphthalene; thiab tiam thib peb ntawm kev ua haujlwm siab dej-txo cov neeg sawv cev los ntawm polycarboxylic acid. Polycarboxylic-hom dej-txo cov neeg ua haujlwm (xws li PC series dej-txo) muaj cov qauv zoo li cov qauv molecular uas muaj kev cuam tshuam zoo heev, tsawg npaum li cas, thiab qhov poob qis tsawg hauv cov pob zeb, ua rau lawv lub ntsiab lus kub hauv kev tshawb fawb thiab kev loj hlob ntawm chemical additives ob leeg hauv tsev thiab txawv teb chaws.

Los ntawm cov qauv molecular foundations, polycarboxylic acid dej-txo cov neeg ua haujlwm nthuav tawm cov duab zuag nrog ntau pab pawg ua haujlwm ntawm cov saw tseem ceeb thiab muaj zog polarity. Cov saw hlau sab muaj cov ntu hydrophilic polyether, nrog rau cov ntu hydrophilic tau ntev dua thiab ntau dua piv rau cov luv luv thiab tsawg dua hydrophobic molecular ntu. Cov qauv ntawm cov polyethylene oxide saw ntu ntawm cov khoom siv polymer sab (tseem hu ua graft chains) cuam tshuam rau cov dej-txo tus nqi thiab slump tuav, zoo heev inhibiting poob poob. Ib tug qauv molecular qauv ntawm polycarboxylic high-performance dej-txo tus neeg sawv cev yog qhia nyob rau hauv daim duab 1:

R1, R2, R3, R5, R6, R7 sawv cev H lossis CH3; R4 sawv cev rau pawg alkyl nrog 1 txog 3 carbon atoms; MI thiab M2 sawv cev rau alkali hlau, alkaline ntiaj teb hlau, los yog ammonium los yog organic amine pawg; a, b, c, d, n, m yog integers.

Raws li kev nkag siab tam sim no ntawm cov dej-txo cov neeg ua haujlwm, lawv feem ntau inhibit lossis cuam tshuam cov qauv flocculated ntawm cov cement hais los ntawm surfactant kev ua, complexation, electrostatic repulsion, thiab steric hindrance. Lub dispersive stability ntawm polycarboxylic acid dej-txo cov neeg ua haujlwm feem ntau yog los ntawm kev cuam tshuam ntawm steric hindrance thiab electrostatic repulsion. Ntawm cov no, electrostatic repulsion muab thawj dispersibility, thaum steric hindrance muaj kev tuav cia.