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Temperature dependence of the complex permittivity in microwave range of some industrial polymers
The microwave properties of a number of polymers common in industry are investigated. A cylindrical resonator in the TM012 mode is used. The cavity perturbation method and detailed COMSOL simulations are applied for extracting the complex permittivity as a function of temperature. The results are useful for the design of plastic processing tools by heating with electromagnetic fields. The intrinsic parameters of absorption are derived based on two exponential decays: polarization and Arrhenius dependence of the decay times on temperature.
Selective cobalt nanoparticles for catalytic transfer hydrogenation of N-heteroarenes
Nitrogen modified cobalt catalysts supported on carbon were prepared by pyrolysis of the mixture generated from cobalt(ii) acetate in aqueous solution of melamine or waste melamine resins, which are widely used as industrial polymers. The obtained nanostructured materials catalyze the transfer hydrogenation of N-heteroarenes with formic acid in the absence of base. The optimal Co/Melamine-2@C-700 catalyst exhibits high activity and selectivity for the dehydrogenation of formic acid into molecular hydrogen and carbon dioxide and allows for the reduction of diverse N-heteroarenes including substrates featuring sensitive functional groups.