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Cataldo F.,University of Rome Tor Vergata | Cataldo F.,Lupi Chemical Research Institute | Ursini O.,CNR Institute of Neuroscience | Cherubini C.,CNR Institute of Neuroscience | Rocchi S.,CNR Institute of Neuroscience
Polymer Degradation and Stability | Year: 2012

Tetrahydrofuran solutions of cis- or trans-polyisoprene react rapidly with a NO 2/N 2O 4 mixture without crosslinking and gelation of the solution (as happens in other solvents) and with formation of a dinitro-adduct (nitro-cis-PIP and nitro-trans-PIP) as the main product. The chemical structure of the adduct was analyzed by FT-IR and UV spectroscopy revealing that species other than the nitro (-NO 2) groups are also present in the adduct, like for instance the nitrate group (-ONO 2). The thermal stability of the adduct was studied by the thermogravimetric analysis (TGA-DTG) combined with differential thermal analysis (DTA). The initial decomposition of the adduct is exothermic and the release of heat reaches its maximum at about 200°C and the completion of the exothermic decomposition occurs at about 325°C. The amount of nitro groups present in the adduct was determined by the TGA-DTG. The decomposition of the adduct was also followed by the TGA-FTIR analytical technique and a certain number of volatile and gaseous species were detected ranging from mixtures of nitrogen oxides and nitroalkanes to NH 3, HCN and CH 4. The adduct nitro-cis-PIP and nitro-trans-PIP yield a carbon foam even at 400°C which can be defined as a crosslinked vitreous carbon foam which was studied by FT-IR spectroscopy. © 2012 Elsevier Ltd. All rights reserved.


Ursini O.,CNR Institute of Neuroscience | Angelini G.,CNR Institute of Neuroscience | Lilla E.,CNR Institute of Neuroscience | Capitani D.,CNR Institute of Neuroscience | And 2 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2013

This paper reports our investigation regarding the thermal properties of new polymer-silica hybrid materials obtained by radiation grafting. The polymer poly(dimethylsiloxane),bis(3-aminopropyl)terminated is γ-grafted on a silica gel surface. The thermal behaviour of γ-grafted hybrid materials reveals remarkable differences compared to the thermal behaviour of physically adsorbed polymers. These differences allow us to assess the ability of γ-rays to produce a polymer chemically bonded on a silica surface. The chemical bonds formed by irradiation give to the polymer a high conformational stability confirmed by DTA analysis. © 2012 Akadémiai Kiadó, Budapest, Hungary.


Angelini G.,CNR Institute of Neuroscience | Ursini O.,CNR Institute of Neuroscience | Cataldo F.,Lupi Chemical Research Institute | Cataldo F.,University of Rome Tor Vergata
Journal of Radioanalytical and Nuclear Chemistry | Year: 2010

Fullerene/silica hybrid materials were obtained by radiation grafting on silica surface of toluene or decalin solutions of C60. As determined by thermogravimetric analysis, the amount of C60 grafted on silica surface was dependent from the radiation dose administered and independent from the C60 concentration and the nature of the organic solvent. In absence of air, a dose of 48 kGy was sufficient to ensure a grafting level of 30% by weight of C60 in the hybrid material. The fullerene/silica hybrid material shows a remarkable thermal stability, since the early decomposition starts above 300 © C as measured by DTG and DTA. The chemical structure of the fullerene/ silica hybrid material was determined by FT-IR spectroscopy and with solid state 13C CP-MAS NMR. The potential application of such materials has been outlined. © 2010 Akadémiai Kiadó Budapest Hungary.

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