INFLUENCE OF THE PREPARATION METHOD ON THE THERMAL PROPERTIES OF PA6/COPOLYMER/ORGANOCLAY NANOCOMPOSITES

The influence of the preparation method on the thermal properties of PA6/Copolymer/Organoclay nanocomposites was investigated. The materials used were PA6, EMA-GMA copolymer and Cloisite™ 20A organoclay. The nanocomposites were prepared in two steps: in the first step the organoclay was pre-intercalated into either PA6 or EMA-GMA terpolymer using an internal mixer at 50 rpm and 240oC for 10 minutes, forming a concentrate. In the second step this concentrate was diluted into either PA6 or PA6/Copolymer blend in a twin screw extruder at 50 rpm and 240oC. Samples were injection molded at 240oC. The nanocomposites were characterized by XRay Diffraction (XRD), Thermogravimetry (TG), Differential Scanning Calorimetry (DSC) and Heat Distortion Temperature (HDT). XRD analysis results indicated that for PA6/EMA-GMA/Organoclay systems, nanocomposites with exfoliated structure were formed, regardless of the preparation method. It was also observed that for the PA6/EMA-GMA/Organoclay nanocomposite in which the clay was pre-intercalated into PA6, the presence of clay increased the intensity of the PA6 ? phase peak, indicating that the clay was located in the PA6 phase. DSC results indicated the presence of one endothermic peak at ~ 212oC which was attributed to the PA6 ? phase and another at ~ 224oC, which was attributed to the PA6 ? phase. For the same nanocomposite, in which the organoclay was pre-intercalated into EMA-GMA terpolymer, no increase on the PA6 ? phase intensity was observed, indicating that the clay was located in the EMA-GMA phase. DSC results showed only one endothermic peak at ~ 224oC attributed to the PA6 ? phase. The absence of the ? phase peak was observed. TG and HDT results showed that the PA6/EMAGMA/Organoclay nanocomposite in which the clay was pre-intercalated into EMA-GMA terpolymer presented higher thermal stability and lower HDT than the same nanocomposite in which the clay was pre-intercalated into PA6.