Synthesis and performance of a series of novel low-molecular-weight superplasticisers with star-shaped phosphate frame

Abstract

A new type of small-molecule phosphate superplasticiser (SP) was synthesised in one pot by the phosphorylation reaction of star-polyether with phosphoric acid. By varying the structure of the initiator polyamines, star-shaped small-molecule phosphate SPs with different molecular weights and anionic charge densities were prepared. The synthesised SPs were characterised by means of proton nuclear magnetic resonance, high-performance liquid chromatography, Fourier transform infrared spectroscopy and gel permeation chromatography. Their dispersion ability, adsorption behaviour and retardation effect on cement hydration were investigated. It was proved that the star-shaped small-molecule phosphate compounds with longer polyether chains and more phosphate groups could be successfully applied as anti-clay SPs. The findings provide useful information for optimising the performance of phosphated small-molecule chemical admixtures in the future.