Thermal degradation of differently substituted Cylopentyl Polyhedral Oligomeric Silsesquioxane (CP-POSS) nanoparticles

Seven variously substituted derivatives ofpolyhedral oligomeric silsesquioxanes (POSSs) with generalformula R7R01 (SiO1.5)8, where R- and R0- were acyclopentyl and a substituted phenyl group, respectively,were prepared in this study, and their compositions werechecked by elemental analysis, 1H NMR and 13C NMRspectroscopy. The compounds obtained were studied byTG and DTA techniques, in both flowing nitrogen andstatic air atmospheres, to draw useful information abouttheir resistance to thermal degradation. Experiments, performedin the 35–700 C temperature range, showed differentbehaviours between the two used atmospheres. Theformation of volatile compounds only, with a near-completemass loss, was observed under nitrogen; by contrast,in oxidative environment, a solid residue (&50% in everycase) was obtained because of the formation of SiO2 asindicated by the FTIR spectra performed. The resultsobtained for the various compounds investigated werediscussed and compared with each other, and heat resistance classifications in the studied environments weremade.