Block copolyurethanes based on polyoxytrimethylene glycols

Trimethylene oxide was polymerized to polyoxytrimethylene glycol by two synthetic routes. High molecular weight polytrimethylene oxide was synthesized using a coordination catalyst system consisting of triethylaluminum, acetylacetone, and water, then ozonized and reduced with lithium aluminum hydride in anhydrous ether to form hydroxyl end‐capped polyoxytrimethylene glycol. In the second route, the polyoxytrimethylene glycols were synthesized directly by the cationic polymerization of trimethylene oxide with boron trifluoride/ethyl ether as catalyst and 1,4 butanediol as co‐initiator. (AB)n block copolyether–urethane–ureas based on these polyoxytrimethylene glycols were synthesized and characterized by differential scanning calorimetry, and dynamic mechanical and stress–strain measurements.