Polypropylene metal functionalised POSS nanocomposites: a study by thermogravimetric analysis

Dimeric and oligomeric Al and Zn-containing isobutyl silsesquioxanes (POSS) were studied to investigate their thermal stability both in inert and oxidant atmosphere, by means of Differential Scanning Calorimetry (DSC) and thermogravimetric analyses (TGA). Thermo-oxidative degradation leads to an important solid residue yield, as a consequence of the POSS oxidation to a thermally stable ceramic phase. The study of the differences in degradation pathways of both metal POSS derivatives clearly shows a competition between two possible mechanisms for product thermal behaviour, namely evaporation and oxidation. The metal POSS compounds were incorporated via melt blending into a PP matrix and the composites thermal properties were studied by thermogravimetric analyses. Thermo-oxidative degradation of composites is strongly affected by the presence of metal containing POSS, resulting in an improved thermal stability, in terms of higher weight loss temperature.