Synthesis, thermal behavior, and kinetics of degradation of alkyl hepta cyclopentyl polyhedral oligomeric silsesquioxanes/polysterene nanocomposites

Abstract

The degradation of polyhedral oligomeric silsesquioxane (POSS)/polystyrene (PS) nanocomposites at different percentages of reinforcement was studied in order to verify their thermal stability in respect to the pristine PS. Analyzed compounds were prepared by in situ polymerization of styrene, in the presence of POSSs and characterized by 1H-NMR. The temperature at 5% mass loss and the activation energy of degradation, determined through kinetics literature methods, were taken into consideration in order to assess both the resistance and the kinetics of degradation. The results obtained for the synthesized polymer and composites were discussed and compared with each other and with those obtained in the past for similar alkyl-POSS/PS nanocomposites. A good improvement of the thermal stability, in respect to neat polymer, was found and showed that the presence of cyclopentyl groups at the vertices of the POSS cage led to a good interaction with the matrix. It was also drawn up a thermal stability classification among the synthesized materials and those studied in the past according to the organic nature of the substituents on the inorganic cage of the composite reinforcement.