Thermal stability of the films of polystyrene chemically bound to fullerene C60:: Effect of film thickness in the submicron range

The thermal stability of polymer films with thicknesses in the submicron range was studied for a composition of polystyrene (PS) chemically bound (grafted) to fullerene C-60 . It is shown that the thermal stability of PS-fullerene (PSF) films depends on their thickness delta. For delta > 10 nm, there appears an additional low-temperature thermal degradation stage, in which the rate of polymer decomposition increases proportionally to the film thickness. The energy parameters of both stages in the thermal degradation kinetics are determined. A decrease in the thermal stability of PSF films is explained by the chemical activity of radicals formed in the initial stage of thermal decomposition of the PSF macromolecules. It is concluded that this effect is indicative of an excessive film thickness and can serve as a probe for the critical film thickness and its inhomogeneity in a submicron range. (C) 2002 MAIK "Nauka / Interperiodica".