Synthesis of poly‐2‐oxazolidones from diisocyanates and diepoxides

Poly‐2‐oxazolidones of high molecular weight have been synthesized from diisocy anates and diepoxides. The synthetic method was first developed for the model compound 3‐phenyl‐5‐phenoxymethyl‐2‐oxazolidone prepared from phenyl isocyanate and phenyl glycidyl ether. Conditions found most suitable for a high yield involve slow addition of isocyanate to a solution of epoxide and catalyst, temperatures of 160°C or higher, and a catalytic amount of n‐butoxylithium in 1‐butanol. The same procedure was used to prepare high molecular weight poly‐2‐oxazolidones. The polymer structure was confirmed by infrared spectroscopy and elemental analysis. All polymers prepared were of sufficient molecular weight to be compression molded. The bulk mechanical properties characterize poly‐2‐oxazolidones as potentially useful engineering thermoplastics. A mechanism for oxazolidone formation is proposed.