Microstructural characterisation and behaviour in different salt solutions of sodium polymethacrylate-g-PEO comb copolymers

Different polycarboxylate polymers (PCPs) have been characterised and their microstructure investigated by size exclusion chromatography, 1H and 13C nuclear magnetic resonance spectroscopy. These polymers are comb-like with a sodium polymethacrylate backbone (PMAANa) on which poly(ethylene oxide) (PEO) chains are randomly grafted as shown by 13C NMR measurements. Since they are mostly used as superplasticisers in cementeous applications, their behaviour has been investigated at high pH in various salt solutions; average radii were determined at room temperature by static and dynamic light scattering and phase diagrams were determined as a function of temperature. We tried to evaluate the influence of different parameters (ion valence, cations, anions, PCP molecular weight, PEO length and grafting degree). A few experiments on homopolymers (PEO and PMAANa) have been equally performed in order to better understand the behaviour of PCPs in solution.