Special structures and thermal stabilities of polyurethanes derived from diol and triol having oxazolidone moieties

Abstract We synthesized regular polyurethanes from the diol having oxazolidone structure (Diol‐1) and the aliphatic diisocyanate by typical polyaddition. The results of the structural analysis suggested that the polyurethane having a cyclic urethane structure such as oxazolidone formed a rod‐like structure, although the control polyurethane having a chain urethane structure formed a linear structure. The polyaddition of Diol‐1 and aliphatic diisocyanate with triol having oxazolidone structure (Triol‐1) as a crosslinker also proceeded successfully to achieve corresponding polyurethanes. However, the polyurethanes containing a molar ratio of Triol‐1 less than or equal 50% were soluble in high polar organic solvents nevertheless those polyurethanes contained some trifunctional units in the polymer chain. On the other hand, the polyurethanes containing a molar ratio of Triol‐1 more than 50% were insoluble in any organic solvents. We hypothesized that the soluble polyurethanes containing Triol‐1 formed multi‐branched structure and the insoluble polyurethanes formed cross‐linking structure. Such structures of polymer chain affected significantly to the thermal properties of the obtained polyurethanes.