Crosslinked polyarylene ether nitrile film as flexible dielectric materials with ultrahigh thermal stability

Dielectric film with ultrahigh thermal stability based on crosslinked polyarylene ether nitrile is prepared and characterized. The film is obtained by solution-casting of polyarylene ether nitrile terminated phthalonitrile (PEN-Ph) combined with post self-crosslinking at high temperature. The film shows a 5% decomposition temperature over 520 degrees C and a glass transition temperature (T-g) around 386 degrees C. Stable dielectric constant and low dielectric loss are observed for this film in the frequency range of 100-200 kHz and in the temperature range of 25-300 degrees C. The temperature coefficient of dielectric constant is less than 0.001 degrees C-1 even at 400 degrees C. By cycling heating and cooling up to ten times or heating at 300 degrees C for 12 h, the film shows good reversibility and robustness of the dielectric properties. This crosslinked PEN film will be a potential candidate as high performance film capacitor electronic devices materials used at high temperature.