Thermal properties of new composites based on nanoclay, polyethylene and polypropylene

The results presented by a number of researchers indicate that the introduction of montmorillonite into polymer matrix results in an increase of thermal stability of polymer nanocomposites. The main purpose of this study was to evaluate the effect of the organoclay on the thermal degradation of polyolefins (polyethylene and polypropylene). Polyolefin-clay nanocomposites were prepared by melt compounding of polyolefins and montmorillonite clay organically modified with 4,4′-methylenebisaniline (MBA) (from 1.5 to 5 wt%). Changes in the surface of montmorillonite and the dispersion of organoclay in the polymer matrix were evaluated using X-ray diffraction (XRD) and elemental analysis. The thermal stability of the clay and nanocomposites were analysed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The XRD results show that almost complete exfoliation of the silicate layers took place and nanocomposite structure was obtained for all new materials. The thermal stability of the PE and PP/clay nanocomposites can be improved in the case of loading above 5 wt%.