Synthesis, characterization and dispersion properties of a series of bis(phosphonic acid)amino-terminated polymers

A series of bis(phosphonic acid)amino-polymers were synthesized in one pot by the Moedrizer-Irani procedure with excellent yields from the single amino-terminated or the double amino-terminated polyethers. The chemical structure and molecular weight of desired products were determined by 1 H, 31 P nuclear magnetic resonance (NMR) and gel permeation chromatography respectively. The experimental results indicated that the single bis(phosphonic acid)amino-terminated polymers not only exhibited good water-reducing properties but also demonstrated effective anti-clay abilities when mixed with polycarboxylate superplasticizers (PCEs). The double amino-terminated polymers showed good fluidity maintaining abilities within 1–3 h. It should be noted that the dispersion properties of the bis(phosphonic acid)amino-polymers were influenced by their molecular weights and structures. What is more, the results of adsorption experiments and theoretical calculations showed that the adsorption ability of bidentate phosphoric acid with calcium ions was much stronger than that of carboxyl group in PCEs.