Characterization of nanoclay intercalation during foaming with in situ energy‐dispersive X‐ray diffraction

The effect of the foaming process on the intercalation of nanoclays in low‐density polyethylene–nanoclay nanocomposites was studied with in situ energy‐dispersive X‐ray diffraction (ED‐XRD) with synchrotron radiation as an X‐ray source. The solid nanocomposites containing different amounts of an organomodified montmorillonite were melt‐blended with blowing agents of different nature and later foamed by heating at atmospheric pressure. During the foaming process, ED‐XRD experiments were performed. These experiments allowed us to measure the time evolution of the interlamellar distance of the clay platelets during the melting and foaming of the nanocomposites; we obtained information about the evolution of the clay structure during the process. The experimental results show that the foaming process induced the intercalation of the clays independently of the blowing agent used. We also proved that the degree of intercalation depended on the expansion ratio reached and that the intercalation produced was larger when the blowing agent was azodicarbonamide. For this particular blowing agent, some interesting effects appeared; these included a catalytic effect of the clays on the decomposition temperature, a partial intercalation of the clays during melt blending, and a very stable structure of the clay particles after foaming. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43432.