Polyarylene ether nitrile composites film with self-reinforcing effect by cross-linking and crystallization synergy

Abstract

Polymer dielectrics with outstanding temperature resistance and mechanical properties are expected to be used in 5G communication systems. Here, self-reinforced cross-linked polyarylene ether nitrile (CPEN) films were rationally designed and fabricated by introducing polyarylene ether nitrile terminated with hydroxyl (PEN-OH) into phthalonitrile end-capped polyarylene ether nitrile (PEN-Ph) and applying post-solid phase chemical reaction. For the catalytic effect on cross-linking reaction and crystallization enhancement of PEN-OH, the comprehensive performance of composite had been greatly improved, which showed a synergistic effect of crosslinking-crystallization. Intriguingly, properties of CPEN films can be finely tuned with the increase of PEN-OH crystallinity. The results show that CPEN films have excellent overall performance with a Tg of 390 °C, a long service life at 300 °C (4.05 × 102 min, 95 wt% residual weight), and low dielectric constant of 2.9. More commendably, CPEN film possessed a higher tensile modulus (3.6 GPa) of over 194% compared to the untreated film due to the crystals immobilized by chemical crosslinking reaction. Tuning the properties of composites by modulating the crosslinking-crystallization behavior opens up a new way to design high-performance polymeric dielectric materials.