Improved mechanical properties of organoclay/nylon 6 nanocomposites prepared via a supercritical carbon dioxide‐aided, melt blending method

The use of supercritical carbon dioxide (scCO 2 ) as a processing aid to help exfoliate nanoclays and improve their dispersion after melt blending in polymer matrices has been reported in the literature by our laboratory and others. Previous work has focused on nonpolar polymers such as polypropylene. In this work, the supercritical carbon dioxide‐aided, melt blending method with single‐screw compounding was applied to an organoclay/nylon 6 composite system with favorable interactions. Wide‐angle X‐ray diffraction, transmission electron microscopy, dynamic mechanical testing, and tensile tests are provided to investigate the effect of processing with scCO 2 on the final composite morphology and properties. It was found that properties of composites prepared with the scCO 2 ‐aided method were similar to or higher than those reported in the literature for samples prepared with twin‐screw compounding. At 7.6 wt% the modulus value reached 4.75 GPa which is one of the highest increases (1.7 GPa) reported for these materials processed at intermediate concentrations. Beyond 7.6 wt% the improvement due to scCO 2 processing matches that of direct blending. It is possible that with the use of a twin‐screw extruder, the modulus would continue to increase. The use of nylon illustrates the importance of having functionalities that can interact with the clay during scCO 2 ‐aided melt compounding. POLYM. COMPOS. 36:527–537, 2015.