Molecular Design, Synthesis and Study of the Viscosity Reduction and Low Air Entrainment Properties of Ester‐Ether Copolymerized Polycarboxylate Superplasticizer

ABSTRACT Traditional polycarboxylic acid‐based water‐reducing agents have several drawbacks, including insufficient synergistic performance, poor adaptability to environmental conditions and raw materials, and temperature sensitivity. This study employs esterification to introduce hydrophobic PO groups as side chains in order to replace conventional hydrophilic polyethylene oxide chains and overcome these issues. This approach yields a novel ester‐ether copolymer polycarboxylate superplasticiser (PCE). Through radical copolymerisation, the ester and ether monomers are grafted onto the backbone to form a dual‐function ‘ester bond‐ether bond’ mechanism. This design combines the advantages of high‐performance polycarboxylate ether and ester superplasticisers, delivering high water reduction rates. The dual‐action mechanism of the ether bond. The resulting compound exhibits high water‐reduction rates and low sensitivity, combining the advantages of both polycarboxylate ether and ester superplasticisers. The study used EO/PO block polyethers esterified with methacrylate to create ester‐modified monomers. These were then subjected to free‐radical polymerization using acrylic acid and ethylene glycol monovinyl polyethylene glycol ether to synthesize a series of EO/PO block ester‐ether copolymer polycarboxylic acid‐based water‐reducing agents. The structure of the synthesized water‐reducing agent was characterized using 1 H‐NMR and FTIR spectroscopy. Results from surface tension measurements, cement paste flowability tests, mortar air content assessments, Marsh time evaluations, and hydration studies demonstrated that the ester‐ether copolymer polycarboxylate water‐reducing agent exhibits high water reduction efficiency and significantly reduces surface tension. It also maintains excellent flowability and lowers air content and paste viscosity whilst retarding the hydration process. Furthermore, PCE's dispersing performance primarily relies on steric hindrance and electrostatic repulsion, while its mild retarding effect stems from the hydrolysis of ester groups.