Preparation and properties of poly(urethane-imide)s derived from amine-blocked-polyurethane prepolymer and pyromellitic dianhydride

• Published in: European polymer journal Vol. 38; no. 3; pp. 487 - 495
• Main Authors: Philip Gnanarajan, T, Padmanabha Iyer, N, Sultan Nasar, A, Radhakrishnan, G
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-03-2002; Elsevier
• Subjects: Applied sciences; Blocked prepolymer; Exact sciences and technology; Mechanical properties; Organic polymers; Physicochemistry of polymers; Poly(urethane-imide); Polycondensation; Preparation, kinetics, thermodynamics, mechanism and catalysts; Thermal stability; Blocked prepolymer; Poly(urethane-imide); Mechanical properties; Thermal stability; Dynamic mechanical properties; Telechelic polymer; Preparation; Deprotection; Imide copolymer; Condensation polymerization; Experimental study; Urethane copolymer; Pyromellitimide copolymer; Etherurethane polymer
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/S0014-3057(01)00216-6

Poly(urethane-imide)s were prepared using amine-blocked-polyurethane (PU) prepolymer and pyromellitic dianhydride. The PU prepolymers were prepared by the reaction of different diols (polypropyleneoxy glycol, polytetramethyleneoxy glycol, polycaprolactonediol and hydroxyl terminated polybutadiene) and different diisocyanates (2,4-tolylene diisocyanate, 1,4-phenelene diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate and 4,4
′-methylenebis(cyclohexyl)isocyanate) and end capped with
N-methylaniline. The polymerization was faster with aromatic isocyanates than with aliphatic isocyanates. The effect of imide content on the thermal and mechanical properties was studied. The poly(urethane-imide)s were characterized by FTIR, GPC, TGA and for dynamic and static mechanical properties. Weight average molecular weight (
M
w) of the polymers did not vary significantly with change in –NCO/–OH ratio where as number average molecular weight (
M
n) increased with increasing –NCO/–OH ratio, correspondingly, the dispersity (PD) decreased. Polymers with higher hard segment content exhibited higher glass transition temperature. The thermal stability of the PU was found to increase significantly by the introduction of imide component.