Low temperature shape memory characteristics of segmented polyurethane-nanoclay composites

Nanocomposites of the segmented polyurethane elastomer with different grades of Cloisite® nanoclay have been prepared. Different characterization techniques viz., X- ray diffraction, scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy have been utilized to investigate the nature of physico-chemical interaction and dispersion of the nanoclay with the polymer matrix. The dimensional stability and the shape memory characteristics of the nanocomposites have been estimated using thermomechanical analysis between −80 and 20 °C by performing two sets of experiments. The experimental parameters e.g., initial temperature, isothermal time and final temperature were varied keeping the applied load common i.e., between 0.25 and 0.75 N in steps of 0.25 N for both sets of experiments. While the dimensional stability of the nanocomposites was found to improve significantly due to addition of nanoclay, the shape fixity and the shape recovery values were found to be almost reversible under the applied loading/de-loading conditions.