Pyrolysis mechanism and electrical properties of 3D-hybrid organic-inorganic materials based on zirconium oxides-hydroxides, 3-butenoates and vinyltrimethoxysilane

This report is focused on the quantitative thermogravimetric-mass spectrometric (TG-MS) analyses and the electrical response of two hybrid organic-inorganic materials (HYP and HYPC), obtained reacting together nanoclusters of zirconium oxides-hydroxides with 3-butenoates and cross-linked with vinyltrimethoxysilane. HYP was cured at 363 K, while HYPC at 403 K. Condensation of the silanol groups, producing shrinkage, alcoholation and the release of 3-butenoic acid and methyl 3-butenoate are the main processes involved in the early stages of pyrolysis from 323 to 633 K. The nominal formula for the two samples with a fair degree of approximation was obtained by elemental analysis and quantitative TG-MS measurements. Morphology of HYP and HYPC is determined by high-resolution transmission electron microscopy. In both HYP and HYPC, the electric response is characterized by a molecular dipole relaxation detected at higher frequencies and an inter-domain polarization phenomenon revealed at the lower frequencies, due to the presence of charged interfaces between nanodomains with different permittivities. HYP material showed a further dipole relaxation at intermediate frequencies, which assists the charge migration process. HYPC, containing a smaller density of 3-butenoate groups, reveals a long-range charge migration event of mobile species by hopping processes between relatively stiff sites.