Thermal and combustion properties of energetic thin films with carbon nanotubes

The effect of varying carbon nanotube concentration on ignition delay, flame speed, and electrical and thermal conductivity of three-dimensional printable energetic thin films made of magnesium and manganese oxide was investigated. Polyvinylidene fluoride was used as the binder for depositing the stoichiometricMg/MnO2 mixture into thin films with an average thickness of 200 μm using an extrusion-based blade-casting method. Four films with a 0, 0.5, 1.0, and 1.5 wt%carbon nanotube were prepared. The ignition delay and flame speed of the films were measured using high-speed imaging techniques. Electrical and thermal conductivities were also measured. Results show that the inclusion of a 1.5 wt%carbon nanotube in the Mg/MnO2/polyvinylidene fluoride films improved their flame speed by 440% and electrical conductance by two orders of magnitude (from 4.23 to 655.33 nS) and decreased ignition delay by 87.2%. Interconnectivity of carbon nanotubes in the films was estimated using a basic percolation model. Films with a 1.5 wt % carbon nanotube demonstrated the highest interconnectivity, which aided improved thermal and electrical energy transport, thereby improving combustion performance. The development of three-dimensional extruded thin films with tailorable thermal and combustion parameters is a precursor for the additive manufacturing of energetic materials.