Preparation and characterization of amphoteric polycarboxylate and the hydration mechanism study used in portland cement

Abstract

A series of comb-like polymer, amphoteric polycarboxylic (APC), was designed as a dispersant for portland cement. APC was synthesized in aqueous solution by macromonomer of butenyl alkylene polyoxyethylene-polyoxypropylene ether (BAPP), sodium methacrylate (SMA), acrylic acid (AA) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (MAEAC). The molecule structure of amphoteric polycarboxylic dispersant was characterized by Fourier transformer infrared (FTIR), and the molecular weight of the APC was determined by gel permeation chromatography (GPC). The dispersion capacity of the APC in cement was also measured. The result shows that the amphoteric polycarboxylic dispersion agent is suitable for portland cement. The APC dispersant with both anionic group and cationic group will provide the better anchoring action with the cement via the adsorption of ions. The hydration mechanism of cement with a certain amount of APC is discussed. We found that the APC could affect the hydration process, which was performed through retarding the generation of ettringite and affecting the crystal enthalpy and its thermal stability in the hydrated product.