Synthesis and properties of multi-armed polycarboxylate superplasticizer modified by β-cyclodextrin

Abstract

The polycarboxylate superplasticizer with a multi-armed structure (multi-armed-PCE) was synthesized via RAFT polymerization of pentaerythritol triacrylate, acrylic acid, macro-monomer polyethylene glycol ether (GPEG) and a certain amount of β-cyclodextrin esterified by maleic anhydride (MA-β-CD). The precise structure of the multi-armed-PCE was characterized by NMR, FTIR, and GPC. Benefitting from the stronger steric hindrance effect provided by the multi-armed topology and MA-β-CD side chains, the polymer exhibited efficient dispersion and fluidity retention properties. As a result, the water reduction rate of the polymer multi-armed-PCE can reach 32.5% under the condition of 0.28% dosage. Compared with comb-like PCE-B, the cement paste containing multi-armed-PCE exhibited better fluidity retention of 2 hours. Moreover, the multi-armed-PCE can significantly increase the mechanical strength of cement hydration products, which can provide potential prospect for the design of high-strength concrete products.