Synthesis of a High-Performance VPEG-Based Polycarboxylate Superplasticizer via Copolymerization and Its Effects on Cement Performance

A high-performance polycarboxylate superplasticizer (VAP-MHC) was developed via free-radical copolymerization of 4-hydroxybutyl vinyl polyoxyethylene ether (VPEG) and acrylic acid (AA), a process critically mediated by a redox initiation system (H2O2/ascorbic acid) and 3-mercaptopropionic acid as a chain transfer agent, with polyethylene glycol-600 incorporated as a nonreactive polymeric additive. This copolymerization strategy, distinct from conventional homopolymerization or simple blending approaches, enables precise architectural control over the polymer backbone, affording the VAP-MHC superplasticizer with exceptional dispersibility and robust slump retention. Under optimized conditions, the synthesized VAP-MHC achieved a cement paste flow of 273 mm and a 28-day compressive strength of 59.7 MPa, significantly outperforming commercial counterparts in both initial fluidity and mechanical development. The enhanced performance is attributed to the synergistic interplay between the VPEG-AA copolymer architecture and the multifunctional additive system, which effectively addresses the persistent trade-off between water reduction and workability loss─a challenge that continues to limit conventional superplasticizers in practical applications.