Preparation and characterization of polyamide 6/polyethylene blend-clay nanocomposites in the presence of compatibilisers and stabilizing system

Several compatibilising systems were added to high-density polyethylene (HDPE) and polyamide 6 (PA6) blends in the presence of an organically modified montmorillonite (OMM). All the blends were prepared by using a co-rotating twin-screw extruder and characterized by SEM, TEM and XRD analyses. In addition, the rheological behaviour and the mechanical properties - tensile and impact - were evaluated. The presence of OMM affects the dimensions of the polymeric phases in the blend but not their mutual adhesion, granted only by the compatibilisers. TEM, SEM and XRD analyses indicated that there is a strict correlation between the compatibilisation level and the final interlayer distance achieved by OMM. Even if some filled compatibilised blends showed a fairly good morphology in terms of phase adhesion, dispersion and dimension the mechanical performance was not so satisfactory. These results were interpreted considering the possible thermo-oxidative degradation of the organic modifier of OMM and the subsequent interaction between and the degradation products and the compatibilising systems. In order to prevent these phenomena, a stabilizing system was added to the nanocomposite blends. In this case, an improvement of mechanical properties was achieved. (C) 2010 Elsevier Ltd. All rights reserved.