Synthesis and performance of a non-air entraining polycarboxylate superplasticizer

Polycarboxylate type superplasticizers (PCEs) typically exhibit strong foaming action. In this study, a non-air entraining polycarboxylate polymer was prepared by grafting polyether amine pendant chains onto a MPEG PCE structure. The molecular properties, such as molar masses (Mw, Mn), the polydispersity index (PDI), and the conversion rate, were obtained via Size Exclusion Chromatography (SEC). The structure of the synthesized PCE polymers was further confirmed via 1H NMR and FTIR Spectrometry. Thereafter, the foaming behavior of the modified PCE polymer was investigated and compared to that of a conventional MPEG PCE polymer. The results of a series of mortar tests revealed that the modified PCE polymer did not entrain air, whereas the conventional MPEG PCE sample developed a high air content of 14.0 vol%. Furthermore, isothermal heat flow calorimetric results and XRD analysis suggested that the modified PCE polymer promoted cement hydration, which in turn accelerated the development of compressive strength.