Effect of Competitive Hydrolysis of Diester In Polycarboxylate Superplasticizer on the Fluidity of Cement Paste

In the synthesis of functional polycarboxylate superplasticizers (PCEs), ester monomer was usually used as small monomer or macromonomer. However, there were few studies on the co-introduction of small ester monomer and ester macromonomer into one PCE molecule and its effects. In this study, it was found an interesting behavior of competitive hydrolysis between these two ester monomers in diester PCE, which performed higher fluidity of cement paste, greater adsorption amount and shorter prolongation of the induction period of cement hydration due to the competitive hydrolysis. Furthermore, the kinetics of hydrolysis and adsorption of the diester PCE were probed, and the rate order was: ester macromonomer < small ester monomer < diester monomers. This study aims to innovatively reveal the special behavior and mechanism of competitive hydrolysis of PCE using diester monomers in cement-based materials and to provide a theoretical basis for enriching molecular design and innovative application of functional PCEs.