Isothermal Crystallization of Nylon-6/Montmorillonite Nanocomposites

Abstract

The isothermal crystallization of in-situ-polymerized and melt-processed nylon-6/montmorillonite nanocomposites was studied by simultaneous small- and wide-angle X-ray scattering using\nsynchrotron radiation. The isothermal crystallization rates, in the nucleation-controlled regime, for the\nnanocomposites are significantly faster than that for the pristine nylon-6 and suggest that the layered\nsilicates act as nucleating centers. Within the experimental resolution, the initial crystal phase formed\nbetween 185 and 205 °C in the presence of the layered silicate is the metastable γ-phase, whereas the\nα-phase develops in the pristine nylon-6 at comparable temperatures. Additionally, the strong silicate−polymer interactions present in the in-situ-polymerized nanocomposites alter the crystallization process,\ncreating a much weaker temperature dependence for the crystallization kinetics. Finally, the presence of\nwell-dispersed layered silicates significantly disrupts the development of lamellar structure but does not\nalter the overall amounts of crystallinity.