Based on a series of cyclic differential scanning calorimetry analyses together with thermogravimetric analyses, the effects of carbon nano-powder and moisture on the glass transition temperature of a polyurethane shape memory polymer were separated and qualitatively identified. This approach should be applicable to other polyurethane polymers and their composites. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.