Narrow strips of various fully imidized polyimide films were stretched under constant load either isothermally or during a temperature ramp. The effects of process variables (load and temperature) on modulus, failure strain, and tensile strength of the stretched films were characterized and room temperature moduli of up to 16 GPa were documented. Several materials that undergo strain-induced crystallization were identified as candidates for further property optimization. (C) 2004 Society of Plastics Engineers.