A comparative study concerning the thermalstability of polystyrene (PS) and six POSS/PS nanocompositesof general formula R7R0(SiO1.5)8/PS (where R =cyclopentyl and R0 = phenyl, 4-methoxyphenyl, 4-tolyl,3,5-xilyl, 4-fluorophenyl, and 2,4-difluorophenyl) wascarried out in both inert (flowing nitrogen) and oxidative(static air) atmospheres. Nanocomposites were prepared byin situ polymerization of styrene in the presence of 5 %w/w of POSS, but the actual filler concentration in theobtained nanocomposites, determined by 1H NMR spectroscopy,was in all cases slightly higher than that in thereactant mixtures. FTIR spectra of nanocomposites evidencedthe presence of filler-polymer interactions. Inherentviscosity (ginh) determinations indicated that the averagemolar mass of polymer in methylated and fluorinatedderivatives was lower than neat PS, and were in agreementwith calorimetric glass transition temperature (Tg) measurements.Degradations were performed into a thermobalance,in the scanning mode, at 10 C min-1, and thetemperatures at 5 % mass loss (T5 %), of various nanocompositeswere determined. The effects of various substituentsof the POSS phenyl group on the thermal stabilityof nanocomposites were evaluated. The results were discussedand interpreted.
A comparative study concerning the thermalstability of polystyrene (PS) and six POSS/PS nanocompositesof general formula R7R0(SiO1.5)8/PS (where R =cyclopentyl and R0 = phenyl, 4-methoxyphenyl, 4-tolyl,3,5-xilyl, 4-fluorophenyl, and 2,4-difluorophenyl) wascarried out in both inert (flowing nitrogen) and oxidative(static air) atmospheres. Nanocomposites were prepared byin situ polymerization of styrene in the presence of 5 %w/w of POSS, but the actual filler concentration in theobtained nanocomposites, determined by 1H NMR spectroscopy,was in all cases slightly higher than that in thereactant mixtures. FTIR spectra of nanocomposites evidencedthe presence of filler-polymer interactions. Inherentviscosity (ginh) determinations indicated that the averagemolar mass of polymer in methylated and fluorinatedderivatives was lower than neat PS, and were in agreementwith calorimetric glass transition temperature (Tg) measurements.Degradations were performed into a thermobalance,in the scanning mode, at 10 C min-1, and thetemperatures at 5 % mass loss (T5 %), of various nanocompositeswere determined. The effects of various substituentsof the POSS phenyl group on the thermal stabilityof nanocomposites were evaluated. The results were discussedand interpreted.
Variously substituted Phenyl hepta Cyclopentyl - Polyhedral Oligomeric Silsesquioxane (ph,hcp-POSS)/Polystyrene (PS) nanocomposites. The influence of substituents on the thermal stability.
BOTTINO, Francesco;BLANCO, Ignazio;
2013-01-01
Abstract
A comparative study concerning the thermalstability of polystyrene (PS) and six POSS/PS nanocompositesof general formula R7R0(SiO1.5)8/PS (where R =cyclopentyl and R0 = phenyl, 4-methoxyphenyl, 4-tolyl,3,5-xilyl, 4-fluorophenyl, and 2,4-difluorophenyl) wascarried out in both inert (flowing nitrogen) and oxidative(static air) atmospheres. Nanocomposites were prepared byin situ polymerization of styrene in the presence of 5 %w/w of POSS, but the actual filler concentration in theobtained nanocomposites, determined by 1H NMR spectroscopy,was in all cases slightly higher than that in thereactant mixtures. FTIR spectra of nanocomposites evidencedthe presence of filler-polymer interactions. Inherentviscosity (ginh) determinations indicated that the averagemolar mass of polymer in methylated and fluorinatedderivatives was lower than neat PS, and were in agreementwith calorimetric glass transition temperature (Tg) measurements.Degradations were performed into a thermobalance,in the scanning mode, at 10 C min-1, and thetemperatures at 5 % mass loss (T5 %), of various nanocompositeswere determined. The effects of various substituentsof the POSS phenyl group on the thermal stabilityof nanocomposites were evaluated. The results were discussedand interpreted.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
