Thermal Behavior of Polyurethane Ionomers Based on Amino Ethers of Orthophosphoric Acid

The products of triethanolamine- and triethylamine-catalyzed reactions of etherification of orthophosphoric acid using poly(oxypropylene glycol)-1000 are studied. It is shown that the nature of tertiary amine markedly influences the completeness of the etherification reaction. When using triethanolamine, its hydroxyl groups are also involved in the etherification of orthophosphoric acid. The resultant tertiary ammonium, which is a central unit of the synthesized branched amino ethers of orthophosphoric acid, is responsible for incomplete etherification and existence of space-separated ionic pairs in the structure of amino ethers. In the case of triethylamine, the etherification of orthophosphoric acid occurs almost completely to yield polyphosphates. The thermal behavior of ionomeric and nonionomeric polyurethanes is investigated. It is found that, for polyurethanes containing ionic groups, the glass transition temperature is much higher than that of nonionomeric polyurethanes. It is shown that phosphorus-containing nonionomeric polyurethanes possess higher thermal stability in inert atmosphere than phosphorous-containing polyurethane ionomers. The onset temperature of the thermal degradation for nonionomeric polyurethanes decreases considerably with an increase in the content of polyphosphates. Polyurethane ionomers synthesized using phospholipids feature a lower thermal stability than polyurethanes based on amino ethers of orthophosphoric acid.