Synthesis of phenolphthalein/bisphenol A‐based poly(arylene ether nitrile) copolymers: Preparation and properties of films

Abstract Poly(arylene ether nitrile) (PEN) is a class of high‐performance engineering plastics of poly(arylene ether) with cyano groups as side groups, which can get improved thermal, mechanical, and electrical properties through simple molecular structure design. In this work, a series of PEN (BPA/PP based PEN) copolymers were synthesized with varying amounts of phenolphthalein and bisphenol A. The influence of the copolymer molecular structure variations on the thermal, mechanical, and dielectric properties of PEN copolymer films was investigated. The results demonstrated that the BPA/PP based PEN copolymer films have great mechanical properties and low dielectric constant, as well as enhanced thermal properties. The highest 5% weight loss temperature of 494.9°C was obtained by PEN‐B7P3, while the highest glass transition temperature of 238.6°C was obtained by PEN‐B3P7. Porous BPA/PP based PEN films prepared by non‐solvent induced phase separation (NIPS) exhibited satisfactory mechanical properties and the highest tensile strength of 9.4 MPa was achieved. Moreover, the introduction of the phenolphthalein structure into the PEN molecular chain can improve the heat resistance of the PEN copolymers without deteriorating the dielectric properties, which gives the copolymers great potential as candidates for applications in flexible electronics and wireless communication.