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

Seven variously substituted derivatives of polyhedral oligomeric silsesquioxanes (POSSs) with general formula R7R1' (SiO1.5)(8), where R- and R'- were a cyclopentyl and a substituted phenyl group, respectively, were prepared in this study, and their compositions were checked by elemental analysis, H-1 NMR and C-13 NMR spectroscopy. The compounds obtained were studied by TG and DTA techniques, in both flowing nitrogen and static air atmospheres, to draw useful information about their resistance to thermal degradation. Experiments, performed in the 35-700 degrees C temperature range, showed different behaviours between the two used atmospheres. The formation of volatile compounds only, with a near-complete mass loss, was observed under nitrogen; by contrast, in oxidative environment, a solid residue (approximate to 50% in every case) was obtained because of the formation of SiO2 as indicated by the FTIR spectra performed. The results obtained for the various compounds investigated were discussed and compared with each other, and heat resistance classifications in the studied environments were made.