Synthesis and performance of a novel amphoteric polycarboxylate superplasticizer with hydrolysable ester group

摘要

A novel hydrolysable cationic monomer of quaternary ammonium dialkyl maleate was synthesized and subsequently copolymerized with acrylic acid and isobutenyl polyethylene glycol to successfully yield an amphoteric polycarboxylate superplasticizer (APC). The effects of the APC on cement particles were systematically investigated. The fluidity, fluidity retention and mechanical properties were measured to evaluate the performances of the APC and compared with those of a polycarboxylate superplasticizer (PCE). In addition, X-ray diffraction, thermogravimetric and scanning electron microscopy characterization were performed to investigate the influences of the APC on cement particles from microscopic level. Furthermore, the interactions of the APC with cement particles were also investigated via adsorption, hydration heat and zeta potential measurements. It was found that the introduction of a hydrolysable cationic monomer could improve the micro-structure and delay the hydration of cement. Moreover, the APC could increase the cement paste fluidity and fluidity retention.