PA66/PA12/clay based nanocomposites: structure and thermal properties

In a previous paper the structure and the physical properties of melt mixed polyamide 66 (PA66)/polyamide 12 (PA12) blends characterized by different compositions have been investigated by means of morphological and physical analyses. A low amount of organically-modified layered silicate (OMLS, 4 wt%) was introduced in order to evaluate its effect on blends structure and components miscibility. This paper completes the characterization of these materials investigating their thermal properties by means of standard and modulated differential scanning calorimetry (DSC, MDSC), dynamic-mechanical analysis (DMA), and thermogravimetric analysis (TGA). The partial miscibility of PA66 and PA12, with phase separation depending on blend composition, has been confirmed by analyzing the glass transition temperature (T(g)) dependence on composition as well as the existence of strong segmental interactions between polymer components. A compatibilizing action of OMLS has been observed because of a lowering of interfacial tension avoiding coalescence phenomena between particles during melt mixing process.