Novel Heat-Resistant Isocyanate- Based Polymers

Abstract

This paper describes the preparation and properties of novel heat- resistant, isocyanate-based polymers. Poly(urethane-oxazolidones) (1/1 molar ratio) were prepared by reaction of NCO-terminated urethane prepolymers with polyepoxides. Poly(urethane-oxazolidone-isocyanurates) (3/3/1 molar ratio) were made by reaction of NCO-terminated urethane prepolymers with triglyci dyl isocyanurate. Poly(urethane-oxazolidone-isocyanurates) (3/3/2 molar ratio) were prepared by trimerization of equimolar mixtures of NCO-terminated urethane prepolymers and an NCO-terminated oxazolidone adduct. The poly(urethane-oxazolidone-isocyanurate) films exhibited very good stress-strain properties at room temperature (22°C), as well as at elevated temperature (150°C). The good thermal stability was also confirmed by TGA. These materials appear to be good candidates for heat-resistant elastomers, coatings, and adhesives. Poly(urethane-isocyanurates) (3/1 molar ratio) were also pre pared, and were compared with oxazolidone containing poly(urethane-iso cyanurates).