Co-reporter:I. Blanco, L. Abate, F.A. Bottino
Thermochimica Acta 2017 Volume 655(Volume 655) pp:
Publication Date(Web):10 September 2017
DOI:10.1016/j.tca.2017.06.019
•Correlation between thermal degradation, solubility and dimensions of substituent in POSSs.•Molecular symmetry variation as a function of the substitution of an atom or a group.•Solubility increase with the substitution of only one hydrogen atom of octaphenyl POSS.Four novel Polyhedral Oligomeric Silsesquioxanes (POSSs) having seven C6H5- groups linked to seven silicon atoms of cage, whilst a substituted −p (C6H4-X) group (X = -CH3, -OCH3, -F, -Cl) is linked to the eighth silicon atom, were synthesized and characterized by elemental analysis and 1H NMR. POSSs were degraded in both inert and oxidative atmosphere, and the temperatures at 5% mass loss (T5%) were determined as a measure of the resistance to thermal degradation. Differential Scanning Calorimetry (DSC) and solubility in CHCl3 and THF experiments were also performed and the results obtained were compared with those found for commercial octaphenyl POSS, which was also here studied. Mono substituted POSSs exhibited slightly lower T5% values and higher solubility than octaphenyl POSS. This behaviour was attributed to symmetry changes determined by the substitution of a hydrogen atom of a POSS phenyl group with various dimensions substituents.
Co-reporter:Ignazio Blanco;Gianluca Cicala
Journal of Thermal Analysis and Calorimetry 2017 Volume 127( Issue 1) pp:147-153
Publication Date(Web):2017 January
DOI:10.1007/s10973-016-5596-2
Polypropylene (PP), due to its chemical stability, is considered one of the main responsible of the increasing amount of plastic wastes on earth. To overcome this problem and to reduce the dependence of oil feedstocks, the use of lignocellulosics as fillers or reinforcements in thermoplastic materials has been increasing enormously in the last decades. In the present work, Liquid Wood (a mixture of cellulose, hemp, fax and lignin) was used to prepare, by mechanical mixing followed by thermal extrusion, blends of various PP/Liquid Wood ratios. Differential scanning calorimetry and thermogravimetric analysis experiments were performed in order to verify whether and how much the composition of the blends affects the thermal properties of the obtained compounds. Both calorimetric and thermogravimetric results indicate that the application of PP as a matrix does not limit the processing temperature of Liquid Wood, which may lead to a perfect marketable composite from these components. The addition of Liquid Wood also resulted in enhanced mechanical properties for the PP/Liquid Wood blends.
Co-reporter:Gianluca Cicala;Giuseppe Saccullo
Journal of Thermal Analysis and Calorimetry 2017 Volume 130( Issue 1) pp:515-524
Publication Date(Web):14 March 2017
DOI:10.1007/s10973-017-6253-0
The effect of processing temperature and time on polylactide/lignin blends was evaluated. Two blends, one commercial and one prepared mixing polylactide (PLA) with different lignin contents, were processed at 190 and 170 °C for different mixing times. The commercial blend was a blend of PLA with 5 mass% of soda lignin and 15.4 mass% of softwood while, for the laboratory-made PLA/lignin, the content of lignin varied from 10 to 25 mass%. Both the blends showed significant degradation of the mechanical properties when processed at 190 °C. The use of lower processing temperature (i.e., 170 °C) showed minor degradation on both the blends. The lignin content showed a marked effect on the degradation behavior of the blends for all the processing temperatures tested.
Co-reporter:Ignazio Blanco, Francesco A. Bottino, Gianluca Cicala, Alberta Latteri, Antonino Recca
Polymer Degradation and Stability 2016 Volume 134() pp:322-327
Publication Date(Web):December 2016
DOI:10.1016/j.polymdegradstab.2016.11.002
Polyhedral Oligomeric Silsesquioxane (POSS)/Polystyrene (PS) nanocomposites were synthesized by in situ polymerization of styrene, in the presence of POSSs of general formula R7R′(SiO1.5)8, where R = phenyl and R′ = -(CH2)7-CH3, and were characterized by FTIR, 1H NMR and SEM spectroscopy, to verify the interaction and dispersion of the filler with/into the polymeric matrix. The kinetic of degradation was studied to find a correlation with the level of POSS dispersion in polymer matrix and to evaluate the resistance to thermal degradation of the synthesized nanocomposites. To this aim, the temperature at 5% mass loss (T5%) was take into consideration and the activation energy (Ea) of degradation were determined through literature method. The results lead us to speculate about the role of the POSS cage vertices on the influence of filler dispersion into the matrix by the comparison with similar alkyl-POSS/PS nanocomposites studied by us in the past. Thermogravimetric analysis (TGA) suggested a good improvement of the resistance to the thermal degradation in respect to neat polymer, and showed that the presence of phenyl groups at the vertices of the POSS cage led to a better dispersion and thus to a thermal stability improvement.
Co-reporter:Ignazio Blanco, Francesco A. Bottino
Polymer Degradation and Stability 2016 Volume 129() pp:374-379
Publication Date(Web):July 2016
DOI:10.1016/j.polymdegradstab.2016.05.005
The thermal behaviour of Polystyrene (PS) based nanocomposites, loaded with different percentage of a novel Polyhedral Oligomeric Silsesquioxane (POSS) of general formula R7R′(SiO1.5)8, where R = phenyl and R′ = (CH2)9CH3, was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were prepared by in situ polymerization of styrene, in the presence of the appropriate POSS, and were characterized by Differential Scanning Calorimetry (DSC), to determine glass transition temperature (Tg), and by FTIR and 1H NMR spectroscopy, to verify and quantify the filler content into the polymeric matrix. Degradations were carried out into a thermobalance at various heating rates in the 25–700 °C temperature range. The characteristic parameters of thermal stability, namely temperature at 5% mass loss (T5%) and the activation energy (Ea) of degradation, were determined. The data obtained were then compared with each other and with those obtained in the past by our group on the mutual alkyl-POSSs/PS nanocomposites to verify the influence of the vertices of POSS cage on the compatibility with the polymeric matrix and on the thermal stability of the synthesized materials.
Co-reporter:I. Blanco, F.A. Bottino, L. Abate
Thermochimica Acta 2016 Volume 623() pp:50-57
Publication Date(Web):10 January 2016
DOI:10.1016/j.tca.2015.11.013
•POSS thermal stability increases with aromatic substituents instead of cycloaliphatic.•Residues at 700 °C were a further confirmation of higher phenyl POSS thermal stability.•Thermal stability linearly increases as a function of (CH2) groups in alkyl chain.Polyhedral Oligomeric Silsesquioxanes (POSSs) of general formula R7R′(SiO1.5)8, where R = isobutyl, cyclopentyl or phenyl and R′ = (CH2)5CH3, (CH2)7 CH3 or (CH2)9CH3, were prepared by corner capping reaction of trisilanols with suitable alkyltriethoxysilane. The compounds obtained were characterized by elemental analysis and 1H NMR spectroscopy, and the results were in very good agreement with those of expected products. The prepared POSSs were degraded in dynamic heating conditions from r.t. to 700 °C, in both inert and oxidative atmospheres, and the temperatures at 5% weight loss (T5%) were determined and compared with each other, in order to investigate how the various groups affect the resistance to thermal degradation. The results did not evidence any substantial difference between the two investigated atmospheres, but indicated clearly an increasing resistance to the thermal degradation according to the following order: isobutyl POSSs < cyclopentyl POSSs < phenyl POSSs. Also, T5% values were linearly increasing as a function of the number of methylene groups in R′ alkyl chain. The results were discussed and suggested a group contribution to thermal stability.
Co-reporter:Ignazio Blanco;Francesco A. Bottino
Journal of Thermal Analysis and Calorimetry 2016 Volume 125( Issue 2) pp:637-643
Publication Date(Web):2016 August
DOI:10.1007/s10973-015-5098-7
A series of novel hepta cyclopentyl bridged polyhedral oligomeric silsesquioxanes (POSSs)/polystyrene (PS) nanocomposites, at different POSS contents (1, 3 and 5 % w/w), was synthesized and characterized. Nanocomposites were prepared by in situ polymerization of styrene in the presence of POSS which has not polymerizable groups, aiming to obtain well-dispersed POSS/PS systems. The actual filler concentration in the obtained nanocomposites was checked by 1H NMR and FTIR spectroscopy. Degradations were carried out into a thermobalance at various heating rates in flowing nitrogen and in a static air atmosphere, and the characteristic parameters of thermal stability, namely temperature at 5 % mass loss (T5 %) and activation energy (Ea) of degradation, of the various nanocomposites were determined. We investigated the influence of the nature of POSSs cage’s periphery on the thermal stability of the obtained materials, and with this aim, we compared the properties of hepta cyclopentyl bridged POSS/PS nanocomposites with those of similar hepta isobutyl bridged POSS/PS ones previously studied. The obtained results were discussed and interpreted.
Co-reporter:Ignazio Blanco, Francesco A. Bottino
Polymer Degradation and Stability 2015 Volume 121() pp:180-186
Publication Date(Web):November 2015
DOI:10.1016/j.polymdegradstab.2015.09.006
The thermal degradation of three hepta cyclopentyl bridged Polyhedral Oligomeric Silsesquioxanes (POSS)/Polystyrene (PS) nanocomposites, at different POSS content (1%, 3% and 5%), was studied and compared with that of similar hepta isobutyl bridged POSS/PS nanocomposites previously studied, in order to investigate the influence of the nature of POSSs cage's periphery on the thermal stability of the obtained materials. Nanocomposites were synthesized by in situ polymerization of styrene in the presence of POSS and the actual filler concentration in the obtained nanocomposites was checked by 1H NMR and FT-IR spectroscopy. The glass transition temperatures (Tg) were determined by Differential Scanning Calorimetry (DSC) while degradations were carried out into a thermobalance, in the scanning mode, at various heating rates in flowing nitrogen and in a static air atmosphere. The characteristic parameters of thermal stability, namely temperature at 5% mass loss (T5%) and the activation energy (Ea) of degradation, of the various nanocomposites were determined and showed a large improvement of thermal stability in respect to those of PS and of analogous isobutyl bridged POSS/PS ones. The results were discussed and interpreted.
Co-reporter:Ignazio Blanco;Francesco A. Bottino;Gianluca Cicala;Giulia Cozzo;Alberta Latteri ;Antonino Recca
Polymer Composites 2015 Volume 36( Issue 8) pp:1394-1400
Publication Date(Web):
DOI:10.1002/pc.23045
A series of three novel dumbbell shaped polyhedral oligomeric silsesquioxanes (POSS)/ polystyrene (PS) nanocomposites, at different POSS contents (3%, 5% and 10% w/w), was synthesized and characterized in order to investigate the effects of this new bridged structure on the filler-polymer interaction and then on the thermal behavior of the obtained polymer nanostructured materials (PNMs). Nanocomposites were synthesized by in situ polymerization of styrene and the actual POSS concentration in the obtained PNMs was checked by 1H NMR spectroscopy. Scanning electron microscopy (SEM) and FTIR spectroscopy evidenced, at the same time, the presence of filler-polymer interactions and auto-aggregation phenomena. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates in both inert and oxidative atmospheres. The characteristic parameters of thermal stability, namely temperature at 5% mass loss and the apparent activation energy of degradation, for the various nanocomposites were determined and an increase in the initial decomposition temperatures of PNMs with increasing the POSS contents was observed. The results are discussed and interpreted. POLYM. COMPOS., 36:1394–1400, 2015. © 2014 Society of Plastics Engineers
Co-reporter:Ignazio Blanco;Lorenzo Abate
Journal of Inorganic and Organometallic Polymers and Materials 2015 Volume 25( Issue 6) pp:1456-1464
Publication Date(Web):2015 November
DOI:10.1007/s10904-015-0259-5
The resistance to the thermal degradation of some polystyrene (PS) based nanocomposites, containing as filler novel aliphatic and aromatic hepta-cyclopentyl bridged polyhedral oligomeric silsesquioxanes (POSSs), was evaluated in both inert and oxidative atmospheres. The fillers were formed by two identical silicon cages R7(SiO1.5)8 (R = cyclopentyl) linked to several aliphatic [–(CH2)2–, –(CH2)6– and –(CH2)10–] and aromatic (Ar, Ar–Ar, Ar–O–Ar and Ar–S–Ar) bridges, where Ar = p-C6H4. Nanocomposites were prepared by in situ polymerization of styrene in the presence of 5 % w/w of appropriate POSS. The actual filler content in the products obtained, checked by 1H NMR spectroscopy, resulted in all cases slightly higher than in starting mixtures. The glass transition temperature (Tg) was also determined by Differential Scanning Calorimetry. The degradation of nanocomposites was carried out into a thermobalance and the temperatures at 5 % mass loss (T5 %) were determined to evaluate the resistance to the thermal degradation which resulted, for the compounds here studied, higher not only than PS, but also than those of the nanocomposites filled with the corresponding hepta-isobutyl POSSs. The results were compared and discussed and suggested that the increments of resistance to thermal degradation in respect to neat PS (T5 % of nanocomposite − T5 % of PS) obey to an additivity group law.
Co-reporter:Ignazio Blanco;Lorenzo Abate
Journal of Thermal Analysis and Calorimetry 2015 Volume 121( Issue 3) pp:1039-1048
Publication Date(Web):2015 September
DOI:10.1007/s10973-015-4655-4
Seven aliphatic and aromatic dumbbell-shaped bridged hepta-cyclopentyl polyhedral oligomeric silsesquioxanes (POSSs), in which two identical silicon cages R7(SiO1.5)8 (with R = cyclopentyl) are linked to various aliphatic [(CH2)n with n = 2, 6 and 10] and aromatic (Ar, Ar–Ar, Ar–O–Ar and Ar–S–Ar, where Ar = p-C6H4) bridges, were prepared through a literature method opportunely modified by us to obtain higher yields. The obtained products were checked by elemental analysis and 1H NMR spectra, and the results were in very good agreement with those of expected products. The synthesized hepta-cyclopentyl POSSs were degraded, in dynamic heating conditions, in both flowing nitrogen and static air atmosphere. The determined temperatures at 5 % mass loss (T5%) and residues at 700 °C evidenced a much better resistance to thermal degradation than the corresponding isobutyl POSSs we investigated in the past. For aromatic POSSs no substantial difference was found between the T5% values in inert environment and those in oxidative atmosphere. By contrast the T5% values of aliphatic POSSs in air were slightly lower than the corresponding ones in nitrogen and decreased, in both environments, on increasing the aliphatic chain length, then showing an opposite trend in respect of the corresponding isobutyl derivatives. This behaviour was interpreted as due to the presence in the POSSs molecules of bulky cyclopentyl groups in the place of smaller isobutyls.
Co-reporter:Ignazio Blanco, Lorenzo Abate, Francesco A. Bottino, Paola Bottino
Polymer Degradation and Stability 2014 Volume 102() pp:132-137
Publication Date(Web):April 2014
DOI:10.1016/j.polymdegradstab.2014.01.029
The thermal degradation of Polystyrene based nanocomposites, containing as fillers novel dumbbell-shaped bridged POSSs in which two identical silicon cages R7(SiO1.5)8 (R = isobutyl), are linked to aliphatic bridges (CH2)n of different lengths (n = 2, 4, 6, 8 and 10), was studied. Various nanocomposites were prepared by in situ polymerization of styrene in the presence of 5% of appropriate POSS. The obtained compounds were characterized by 1H NMR spectroscopy, to verify their actual filler content, which was slightly higher than that in starting mixtures, and by Differential Scanning Calorimetry (DSC) to determine glass transition temperature (Tg). Thermogravimetric (TG) and Differential Thermogravimetric (DTG) analysis, in both flowing nitrogen and static air atmosphere, were carried out and temperatures at 5% mass loss (T5%) were determined to investigate the resistance to the thermal degradation. The results obtained for various samples were compared with each other and with those of virgin Polystyrene, and were interpreted and discussed.
Co-reporter:Ignazio Blanco;Francesco A. Bottino;Gianluca Cicala;Alberta Latteri ;Antonino Recca
Polymer Composites 2014 Volume 35( Issue 1) pp:151-157
Publication Date(Web):
DOI:10.1002/pc.22644
Variously substituted polyhedral oligomeric silsesquioxanes (POSSs)/polystyrene (PS) nanocomposites of general formula R7R′(SiO1.5)8/PS (where R = isobutyl and R′ = 4-methoxyphenyl, 4-methylphenyl, 3,5-dimethylphenyl, 4-fluorophenyl, 2,4-difluorophenyl, 4-chlorophenyl) were prepared by in situ polymerization of styrene in the presence of 5% w/w of POSS. The actual filler concentration in the obtained nanocomposites was checked by 1H NMR spectroscopy. Scanning electron microscopy and FTIR spectroscopy evidenced the presence of filler-polymer interactions. Inherent viscosity (ηinh) determinations indicated that the average molar mass of polymer in halogenated derivatives was lower than neat PS, and were in agreement with calorimetric glass transition temperature (Tg) measurements. Finally, a comparative study concerning the thermal stability of synthesized nanocomposites was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres into a thermobalance, in the scanning mode, at 10°C min−1, and the temperatures at 5% mass loss (T5%), of various compounds were determined. The results were discussed and interpreted. POLYM. COMPOS., 35:151–157, 2014. © 2013 Society of Plastics Engineers
Co-reporter:Ignazio Blanco
Chinese Journal of Polymer Science 2014 Volume 32( Issue 6) pp:681-689
Publication Date(Web):2014 June
DOI:10.1007/s10118-014-1453-6
A long-term (about nine months) isothermal degradation experiment of two different commercial polylactide (PLA) samples used for food packaging was carried out at a relatively low temperature (423 K). Thermooxidative degradations of the same polymers were carried out in a thermogravimetric (TG) analyser, at higher temperatures (453 K ≤ T ≤ 523 K), under isothermal heating conditions. The obtained set of experimental TG data was used to determine the apparent activation energy (Ea) of degradation through two isothermal kinetic methods. The results from long-term experiment evidenced considerable mass loss for both PLA samples in the investigated period, but the experimental data were not in agreement with those from the short-term degradations at higher temperatures, thus suggesting a different degradation kinetics, and, then a low reliability of the lifetime predictions for polymers in service or degradation forecasts for the end of their life based on experiments at higher temperatures.
Co-reporter:Ignazio Blanco;Lorenzo Abate
Journal of Thermal Analysis and Calorimetry 2014 Volume 116( Issue 1) pp:5-13
Publication Date(Web):2014 April
DOI:10.1007/s10973-013-3487-3
Five new dumbbell-shaped polyhedral oligomeric silsesquioxanes (POSSs), in which two identical silicon cages are linked to various length aliphatic bridges, were prepared by corner capping reaction between hepta isobutyltricycloheptasiloxane trisilanol (HIBT) and suitable bis(triethoxysilyl) derivatives. The products obtained were characterized by elemental analysis and 1H NMR spectroscopy, and the results were in very good agreement with the expected ones. Degradations were carried out in flowing nitrogen and in static air atmosphere, and temperatures at 5 % mass loss (T5 %) and residues at 700 °C were determined to investigate the resistance to the thermal degradation. The T5 % values were lower in oxidative atmosphere than in inert environment, and increased linearly as a function of organic bridge length in either used atmosphere. The residues at 700 °C were higher in static air than in flowing nitrogen. The results obtained for various dumbbell-shaped POSSs were discussed and compared with each other. A comparison with the results previously obtained with the corresponding un-bridged phenyl, hepta isobutyl-POSSs showed a higher resistance to the thermal degradation of bridged POSSs.
Co-reporter:Ignazio Blanco, Lorenzo Abate, Marta Letizia Antonelli, Francesco Agatino Bottino
Polymer Degradation and Stability 2013 Volume 98(Issue 11) pp:2291-2296
Publication Date(Web):November 2013
DOI:10.1016/j.polymdegradstab.2013.08.012
The kinetics of the isothermal degradation in static air atmosphere of four well known polymers, polyethylene (PE), polystyrene (PS), polycarbonate (PC) and poly(methyl methacrylate) (PMMA) was studied by both a long-term (more than three years) experiment at relatively low temperature (423 K) and a set of short-term experiments at higher temperatures. The activation energy (Ea) values of degradation were determined by both the MacCallum and Wilkinson literature methods, and were compared with those obtained through a new very simple method we set up, based on the direct regression of TG mass loss data. About two years ago we published the results concerning PE and PS because their mass losses during long-term experiments were sufficiently high. The long-term degradation experiments were continued until now and in this second part we report the results concerning PC and PMMA. The degradation Ea values calculated from short-term experimental data through the three different methods were in good agreement with each other for both PC and PMMA, thus confirming the general applicability of our simple method for the determination of Ea. The experimental data at lower temperature of PC were not in agreement with those at higher temperatures, thus confirming the low reliability of the kinetic parameters (and then of lifetime predictions) at low temperature determined by experiments at higher temperatures. Partially disagreeing results were obtained for PMMA, which were discussed and interpreted.
Co-reporter:Ignazio Blanco, Francesco A. Bottino, Gianluca Cicala, Alberta Latteri, Antonino Recca
Polymer Degradation and Stability 2013 Volume 98(Issue 12) pp:2564-2570
Publication Date(Web):December 2013
DOI:10.1016/j.polymdegradstab.2013.09.017
The thermal degradation of a series of three novel bridged polyhedral oligomeric silsesquioxanes (POSS)/polystyrene (PS) nanocomposites, at different POSS content (3%, 5% and 10%), was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres, in order to investigate the effects of this new dumbbell-shaped structure on the filler–polymer interaction and then on the thermal stability of the obtained materials. Nanocomposites were synthesized by in situ polymerization of styrene in the presence of POSS which has not polymerizable groups, aiming to obtain well dispersed POSS/PS systems. The actual filler concentration in the obtained nanocomposites was checked by 1H NMR spectroscopy. Scanning electron microscopy (SEM) and FTIR spectroscopy evidenced the presence of filler–polymer interactions. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates, and the characteristic parameters of thermal stability, namely temperature at 5% mass loss (T5%) and the activation energy (Ea) of degradation, of the various nanocomposites were determined. The results were discussed and interpreted.
Co-reporter:Ignazio Blanco;Francesco Agatino Bottino
Polymer Composites 2013 Volume 34( Issue 2) pp:225-232
Publication Date(Web):
DOI:10.1002/pc.22400
Abstract
A comparative study concerning the thermal stability of polystyrene (PS) and three polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R7R′(SiO1.5)8/PS (where R = isobutyl and R′ = phenyl), at various (3, 5, and 10%) POSS concentration was carried out in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Nanocomposites were synthesized by in situ polymerization of styrene in the presence of POSS and the experimental filler concentration in the obtained compounds, determined by 1H NMR spectroscopy, was in all cases slightly higher than that in the reactant mixtures. Inherent viscosity (ηinh) determinations indicated that the average molar mass of polymer in the nanocomposites was practically the same than neat PS and were in agreement with calorimetric glass transition temperature (Tg) measurements. The temperature at 5% mass loss (T5%) and the activation energy (Ea) of degradation process of synthesized nanocomposites were determined and compared with each other and with those of unfilled PS. On the basis of the results from thermal and IR spectroscopy characterizations, nanocomposite with 5% of molecular filler appears the most thermally stable. The results were also compared with literature data on similar PS-based nanocomposites. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers
Co-reporter:Ignazio Blanco;Francesco Agatino Bottino;Paola Bottino
Polymer Composites 2012 Volume 33( Issue 11) pp:1903-1910
Publication Date(Web):
DOI:10.1002/pc.22330
Abstract
The thermal degradation of two polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R8(SiO1.5)8 POSS/PS and R′1R7(SiO1.5)8 POSS/PS (where R′ = Phenyl and R = Cyclopentyl), at 5% of POSS concentration, was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Compounds were prepared by the polymerization of styrene in the presence of POSS. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates, and the obtained thermogravimetric (TG) curves were discussed and interpreted. The initial decomposition temperature (Ti), the temperature at 5% mass loss (T5%), the glass transition temperature (Tg), and the activation energy (Ea) of degradation of nanocomposites were determined and compared with each other and with those of unfilled PS. The Ti, T5%, and degradation Ea values of nanocomposites were higher than those of neat PS, thus indicating a better heat resistance and lower degradation rate, and then a better overall thermal stability. The use of POSS with a symmetric structure, in the synthesis of PS based nanocomposite, showed a decrease of Tg value not only in respect to asymmetric POSS/PS nanocomposite but also in respect to neat polymer, thus suggesting an influence of filler structure in the thermal properties of the materials. POLYM. COMPOS., 33:1903–1910, 2012. © 2012 Society of Plastics Engineers
