Impact of polycarboxylate superplasticizers (PCEs) with novel molecular structures on fluidity, rheological behavior and adsorption properties of cement mortar

Abstract

Polyether macromonomers have shown diversified structures recently. In this work, a series of polycarboxylate superplasticizers (PCEs) were synthesized via copolymerization using a novel macromonomer, ethylene–glycol monovinyl polyethylene glycol (EPEG). The molecular structures were modified by varying the side chain length, carboxylate density and integrating sulfonic group. The synthesis reaction of PCEs with high reaction conversion ratio was achieved through rapid reaction(20–30 min) at low temperature (5-20℃). The fluidity of PCEs, the rheological parameters and the compressive strength of mortar were measured. The adsorption behavior and zeta potential of the cement particles were also measured. Results have shown that PCEs with short side chain and high carboxylate density had high adsorption ability, high dispersion capacity in mortar. In addition, PCEs with sulfonic group had increased adsorption amount on the cement surface. These results could allow further progress in the application of EPEG macromonomer.