Investigation on Unusual Crystallization Behavior in Polyamide 6/Montmorillonite Nanocomposites

Abstract

The crystallization behavior and crystal structure of polyamide 6/montmorillonite (PA6/MMT) nanocomposites were investigated by differential scanning calorimetry and X-ray diffraction, and an interesting behavior was observed. The material was prepared via melt compounding using an organophilic clay obtained by co-intercalation of epoxy resin and quaternary ammonium into Na-montmorillonite. A maximum in degree of crystallinity was obtained at 5 wt.-% MMT and the reasons for this, based on the MMT layer distribution, were discussed. The degree of crystallinity showed a strong dependence on the cooling rates. In contrast with typical behavior, a higher cooling rate resulted in a higher degree of crystallinity. In nanocomposites, the γ-crystalline phase was dominant.