Authors:S. Gomes, F. Margaça, L. Ferreira, I. Miranda Salvado, and A. Falcão
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.
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
Silicate hybrid materials were prepared by the sol–gel process with the addition of x mass% of zirconium propoxide (x = 0 and 1). The thermal behaviour as well as the influence of Zr addition was studied by thermal gravimetric analysis and differential thermal analysis. The microstructure evolution with temperature was investigated by X-ray diffraction and small-angle neutron scattering. It was found that the beginning of polymer degradation occurs at a higher temperature in the material prepared with addition of Zr than in the one prepared without. At the nanometric scale, the materials prepared without Zr show smooth interfaces, whereas those with Zr present a mass fractal structure. This structure is also observed in the material without Zr after thermal treatment at 200 °C. The results showed that bioactivity is favoured by mass fractal structures in comparison with one consisting of smooth surfaces.