AbstractTwo PA 6/clay nanocomposites, NCN5 and NCN10 with 5 and 10% (wt %) clay, respectively, were prepared by a twin screw extruder. The effects of annealing including solid-state annealing and melt-state annealing on the polymorphic behavior and thermal property of nanocomposites have been comparatively studied as a function of annealing time using Modulated Differential Scanning Calorimetry (MDSC). It was demonstrated that NCN5 and NCN10 exhibit a similar polymorphic behavior when they were annealed in solid-state for different durations. As the annealing temperature was elevated to 245 °C (melt-state annealing), significant differences in thermal behavior and polymorphism between NCN5 and NCN10 could be found. For NCN5, the α structure became the absolutely dominating crystalline phase independent of the annealing durations, for NCN10, however, the formation of γ structure is greatly enhanced and longer annealing time would amplify this phenomenon. Moreover, a low-temperature endothermic peak was observed around 180 °C in both NCN5 and NCN10 samples which was also found to strongly depend on the thermal history.
