Study on the synthesis and performance of different chain transfer agent types and high water-reducing olycarboxylate superplasticizer

The isobutenol polyoxyethylene ether (HPEG) is polyether macromonomer, and acrylic acid (AA) is small comonomer. The high water-reducing polycarboxylate superplasticizer (PCE) is synthesized by free radical polymerization and the influence of different acid-ether ratio, type and dosage of chain transfer agent on the dispersion of PCE was studied and the optimal synthesis process was explored. The structure and properties of PCE are tested by gel permeation chromatography (GPC) and other characterization. The results showed that the optimal synthesis process was as follows: acid ether ratio was 4.50, Vitamin C, H2O2 and 2-Hydroxy-1-ethanethiol accounted for 0.80%, 0.20% and 0.56% of the mass percentage of large monomer, respectively. The type of chain transfer agent was sodium hypophosphate and 2-Hydroxy-1-ethanethiol, the comprehensive performances (dispersion, retention, mechanical properties) were better.