POLYURETHANE IONOMERS CONTAINING PHOSPHATE GROUPS

A new ionic diol, the monosodium salt of beta-glycerophosphoric acid, was synthesized. The commercially available disodium salt was first converted to the beta-glycerophosphoric acid which was then neutralized with the requisite amount of sodium hydroxide to yield the monosodium salt of the acid. The monosodium salt was soluble in DMSO, in contrast to the disodium salt, which was found to be insoluble in almost all solvents with the exception of water. The monosodium salt of glycerophosphoric acid (GPA-Na) was used subsequently as a chain extender diol in the two-step synthesis of polyurethane ionomers using also butane-1,4-diol, polypropylene glycol and diphenylmethane-4,4'-diisocyanate. The reaction was catalysed by using a trace of dibutyl tin dilaurate. Both the ionic diol and the polyurethane ionomers were characterized using FTi.r., H-1 n.m.r. and P-31 n.m.r. Differential scanning calorimetry was also performed using these polymers.