Synthesis and properties of crosslinked poly(arylene ether nitriles) containing pendant phthalonitrile

Synthesis of poly(arylene ether nitrile) and carboxyl-functionalized poly(arylene ether nitrile) with high thermal stability and their thermal decomposition kinetics

Poly(arylene ether nitrile)s (PAENs) play an important role in special engineering materials owing to their excellent mechanical strength and superior thermal stability. In this study, PAEN and carboxyl-functionalized poly(arylene ether nitrile) (CPAEN) were successfully synthesized and their thermal parameters were determined through thermogravimetric analysis and differential scanning calorimetry to investigate the thermal decomposition kinetics and thermal stability. The results indicate that both PAEN and CPAEN exhibited high glass transition temperature and initial decomposition temperature. Meanwhile, the effects of the side groups on the thermal stability and the decomposition kinetic parameters of PAEN and CPAEN under nitrogen were discussed systematically. The kinetic parameters of PAEN and CPAEN were determined using the Kissinger and Ozawa methods, respectively. It reveals that the activation energy ( E) values of PAEN obtained using the Kissinger and Ozawa methods were 192.45 and 206.63 kJ/mol, and the corresponding E values of CPAEN were 161.20 and 162.72 kJ/mol, respectively. The thermal decomposition mechanism of PAEN and CPAEN obtained from Coats–Redfern methods goes for F3and D1models, respectively.

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 °C and a glass transition temperature (T_g) around 386 °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 °C. The temperature coefficient of dielectric constant is less than 0.001 °C⁻¹ even at 400 °C. By cycling heating and cooling up to ten times or heating at 300 °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.