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Abstract  

Hybrid materials were prepared by γ-irradiation of a mixture of polydimethylsiloxane (PDMS), with tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr), using a 60Co γ source, without any addition of solvents. Thermogravimetry, differential scanning calorimetry and X-ray diffraction measurements showed that the obtained hybrids are amorphous materials of the nanocomposite type. The results highlighted the different influence of each of the metallic alkoxides on the hybrid structure. The material rupture temperature, associated with the degradation of the organic component, depends mainly on the TEOS content, whereas the inorganic component structural stability depends on the relative PrZr content in the alkoxides mixture.

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Journal of Thermal Analysis and Calorimetry
Authors: Hieronim Maciejewski, Izabela Dąbek, Ryszard Fiedorow, Michał Dutkiewicz, and Mariusz Majchrzak

meet requirements set by new directions of applications. In recent years, studies on modern hybrid materials of extraordinary and unprecedented properties became one of the most thriving activities in the field of materials chemistry [ 1 – 3 ]. The term

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Journal of Thermal Analysis and Calorimetry
Authors: J. J. H. Lancastre, F. M. A. Margaça, L. M. Ferreira, A. N. Falcão, I. M. Miranda Salvado, M. S. M. S. Nabiça, M. H. V. Fernandes, and L. Almásy

-ethyl-ortho-silicate (TEOS) and polydimethylsiloxane (PDMS) have been the focus of attention due to their unique properties such as high flexibility and low elastic modulus together with high mechanical strength [ 6 ]. In these materials, also known as hybrid materials, the

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Abstract  

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.

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Introduction Organic–inorganic hybrid materials have gained much attention, which is because that they combine advantages of organic and inorganic materials. Many reports focus on fabrics treated with hybrid materials. Satoh et

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Journal of Thermal Analysis and Calorimetry
Authors: M. Zaharescu, A. Jitianu, A. Brãileanu, V. Bãdescu, G. Pokol, J. Madarász, and Cs. Novák

Abstract  

The hydrolysis-polycondensation of organically modified Si-alkoxides leads to the obtaining of inorganic-organic hybrid materials in which the organic moieties remain as permanent groups bonded to the inorganic network. The molecular species previously determinated by GC-MS during the gelation process have been significantly different according to the type of the alkoxide used. In the present work, thermal stability of SiO2-based inorganic-organic hybrid materials starting with TEOS (tetraethoxysilan), MTEOS (triethoxymethylsilan), VTEOS (triethoxyvinylsilan) and MTMOS (trimethoxymethylsilan) was studied. The molecular structure of the gels obtained determines differences in their thermal behaviour. Gels obtained starting with MTEOS show the highest thermal stability, while gels obtained using VTEOS the lowest, among the substituted alkoxides. A particular behaviour presents the gel obtained with MTMOS that decomposes in four steps. This could be explained by the presence in the gel of some prevalent types of molecular species with different thermal stability.

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Abstract  

It is well known that SiO2 -based inorganic-organic hybrid materials present significant differences due to the organic moieties bound to the inorganic network and to the preparation conditions. In the present work the ageing effect on the thermal stability of the SiO2 -based inorganic-organic hybrid materials prepared using tetraethoxysilan (TEOS), triethoxymethylsilan (MTEOS), triethoxyvinylsilan (VTEOS), tetramethoxysilan (TMOS), trimethoxymethylsilan (MTMOS) and trimethoxyvinylsilan (VTMOS) was studied. TG/DTA-MS was used to study the decomposition process of the materials. The structural modifications of the materials during ageing were studied using spectral methods. The gels obtained starting with more reactive alkoxides, of methoxy-type, present more complex structures and are less stable during ageing.

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Abstract  

The thermal behaviour of an epoxy resin cured with an amine-POSS was studied using differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The kinetic of polymerization reaction and the thermal degradation have been analyzed based on an iso-conversional model. The obtained results showed that the activation energies of both processes depend on the degree of conversion.

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Journal of Thermal Analysis and Calorimetry
Authors: Maria J. F. Costa, Antonio S. Araujo, Edjane F. B. Silva, Mirna F. Farias, Valter J. Fernandes Jr., Petrus d’Amorim Santa-Cruz, and José G. A. Pacheco

one microporous crystalline phase associated with a non-crystalline mesoporous phase, having a combined micro-mesoporous structure. This new class of hybrid materials has attracted a great deal of attention due to their potential applications in

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