Evaluation of thermal degradation mechanisms and their effect on the gross calorific value of ABS/PC/organoclay nanocomposites

In this work, nanocomposites of ABS/PC blends reinforced with organically modified montmorillonite (OMMT) were prepared by melt blending in a twin screw extruder, and an assessment of the thermal degradation mechanisms was performed by thermogravimetric analysis. The incorporation of PC improves the thermal resistance of ABS/PC blends, with respect to pure ABS. The addition of OMMT alters the degradation mechanism and modifies the properties of blends with higher PC content, where an increase of the degradation temperature corresponding to PC becomes obvious, in comparison with the respective unreinforced blends. The gross calorific value was calculated using an oxygen bomb calorimeter, and in most of the examined nanocomposites, an inverse trend was observed between this property and the residue calculated after thermogravimetric analysis in inert atmosphere. Based on the above results, the thermal degradation behavior of ABS/PC nanocomposites was interpreted by the heat barrier effect, caused via the formation of a carbonaceous silicate char, which insulates the underlying material creating a protective barrier to heat and mass transfer.