Investigation on phenolphthalein and bisphenol AF based Poly(arylene ether nitrile) copolymers: Preparation, thermal, mechanical and dielectric properties

Poly (arylene ether nitrile) (PEN) is a kind of high-performance engineering plastic and their properties can be tuned by the copolymerization of various structural diphenols and dichloro (fluoro)-benzonitrile. In this work, a series of phenolphthalein and bisphenol AF based PEN (PP/BPAF-PEN) copolymers were designed and synthesized. Structures, molar weights, mechanical and thermal properties were studied. Results showed that PP/BPAF-PEN copolymers were successfully synthesized and exhibited good compatibility, outstanding thermal and mechanical properties. Besides, PP/BPAF-PEN exhibited excellent Tg up to 260 °C (DSC), tensile strength of 120 MPa, high Td5% and char yields (>70%). With incorporation of –CF3 into molecular chains, dielectric constant of PP-PEN (3.41 at 1 MHz) was decreased to 3.05 of PP/BPAF-PEN and dielectric loss was around 0.01. Hence, the obtained PP/BPAF-PEN copolymers possessing excellent properties could be applied as the candidates in flexible printed circuit (FPC) substrate.