Variously substituted phenyl hepta cyclopentyl-polyhedral oligomeric silsesquioxane (ph,hcp-POSS)/polystyrene (PS) nanocomposites: The influence of substituents on the thermal stability

• Published in: Journal of thermal analysis and calorimetry 2013-04, Vol.112 (1), p.421-428
• Main Authors: Blanco, Ignazio, Abate, Lorenzo, Bottino, Francesco Agatino
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences
• ISSN: 1388-6150; 1572-8943
• DOI: 10.1007/s10973-013-2997-3

A comparative study concerning the thermal stability of polystyrene (PS) and six POSS/PS nanocomposites of general formula R 7 R′(SiO 1.5 ) 8 /PS (where R = cyclopentyl and R′ = phenyl, 4-methoxyphenyl, 4-tolyl, 3,5-xilyl, 4-fluorophenyl, and 2,4-difluorophenyl) was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were prepared by in situ polymerization of styrene in the presence of 5 % w/w of POSS, but the actual filler concentration in the obtained nanocomposites, determined by 1 H NMR spectroscopy, was in all cases slightly higher than that in the reactant mixtures. FTIR spectra of nanocomposites evidenced the presence of filler-polymer interactions. Inherent viscosity ( η inh ) determinations indicated that the average molar mass of polymer in methylated and fluorinated derivatives was lower than neat PS, and were in agreement with calorimetric glass transition temperature ( T g ) measurements. Degradations were performed into a thermobalance, in the scanning mode, at 10 °C min −1 , and the temperatures at 5 % mass loss ( T 5 % ), of various nanocomposites were determined. The effects of various substituents of the POSS phenyl group on the thermal stability of nanocomposites were evaluated. The results were discussed and interpreted.