A novel two component polyurethane sealant has been prepared. Component A, known as prepolymer, is synthesized by capping hydroxy-terminated polybutadiene (HTPB) with toluene diisocyanate. Component B, known as hardener, comprises of a polyol (polyoxypropylene triol) as crosslinker and 4,4'-diamino-3,3'-dichlorodiphenylmethane (DADCDPM) and 4,4'-diamino-3,3'-dichlorotriphenylmethane (DADCTPM) as chain extenders and fillers. Evaluation of mechanical properties and aging studies indicate that the sealant has excellent mechanical properties and stability in different environment. (c) 2005 Wiley Periodicals, Inc.