Synthesis of Poly(Urethane-Imide): Effect of Solvents with and without Basic Nitrogen Atom and Other Parameters on the Imide Formation Reaction Between Blocked-Isocyanate Prepolymers and Pyromellitic Dianhydride. - Nasar, A.Sultan; Raghavan, A.; Kumar, V.Siva (Journal of Macromolecular Science: Pure & Applied Chemistry, 2005)