Effect of Polycarboxylate Superplasticizer with Different Adsorption Groups on Plastic Viscosity of Cement Paste
In order to reveal the effects of different adsorption groups of the main chains on cement adsorption and dispersion and rheological properties of cement paste,polycarboxylate superplasticizer with different adsorption groups were prepared by radical polymerization of acrylic acid(AA)of monocarboxylic acid adsorption group,maleic anhydride(MA)of dicarboxylic acid adsorption group,isoacrylphosphonic acid(IPPA)of phosphoric acid adsorption group and isoprenyl alcohol polyoxyethylene-polyoxypropylene ether(IPE12PP3G,Mw=762).Three kinds of superplasticizer with the same acid-ether ratio,main chain polymerization degree,side chain length and side chain but different adsorption groups were prepared.The molecular weight,molecular distribution and structural information of the synthetic products were analyzed by gel permeation chromatography(GPC),infrared spectroscopy(FT-IR),and nuclear magnetic hydrogen spectroscopy(1H-NMR).And its complexing capacity,hydrodynamic radius,adsorption capacity,Zeta potential,adsorption layer thickness and hydration heat release rate were determined.The results show that the superplasticizer synthesized with maleic anhydride of dicarboxylic acid adsorption group shows stronger complexation ability(the chemical shift between Ca2p binding energy and blank sample is 0.17 eV and 0.07 eV,respectively),smaller hydrodynamic radius(5.46 nm),higher adsorption capacity(2.65 mN/m2),bigger Zeta potential(-26.507 mV)and thicker adsorption layer thickness(1.16 nm),and the hydration heat release rate of cement is still relatively slower than other two superplasticizers.
万方数据
维普
