Study on the polycarboxylate superplasticiser by dual initiator synthesis: performance, polymerisation mechanism and microstructure

Polycarboxylate superplasticiser (PCE) has great significance in the development of high-performance cement-based materials. At present, a single initiator is mostly used in the synthesis of PCE, but no researchers have investigated whether a dual initiator can improve its performance and the related mechanism. In this study, PCEs were synthesised innovatively by dual initiator method (PCE-dual). The results showed that PCE-dual exhibited an excellent dispersion performance with a fluidity retention of 74.2% after 4 h and the highest final conversion (97.4182%). Furthermore, the working mechanism of the dual initiator was discussed in detail. The decomposition rate constant kd of the dual initiator was the highest, and the actual acrylic acid:α-methallyl-ω-methoxy poly(ethylene glycol) ratio in the PCE-dual molecule was closer to the initial feeding ratio by the calculation from 1H nuclear magnetic resonance spectra. The aims of this study are to provide an efficient avenue to improve the performance of PCE, and to interpret the mechanism of the contribution of optimising the initiation system.