In situ catalyzed and reinforced high‐temperature flexible crosslinked ZnO nano‐whisker/polyarylene ether nitriles composite dielectric films

Zinc oxide nano‐whiskers (ZnO‐nws) with the aspect ratio of about 30 are prepared via hydrothermal method and characterized by XRD and SEM. Then, the ZnO‐nws are doped into polyarylene ether nitriles terminated with phthalonitrile (PEN‐Ph) to fabricate the ZnO‐nws/PEN‐Ph crosslinked composite films. The crosslinking density, thermo‐stability, dielectric property, microstructure and mechanical property are investigated in detail. According to the DSC test, the ZnO‐nws can be served as catalyst for the crosslinking reaction of phthalonitrile. Under the same condition, the crosslinking density of the composites is determined by the weight content of ZnO‐nws, and is 5.45 × 10⁻² mol/cm³ when 4 wt% of ZnO‐nws is incorporated. The TGA and DSC results show that the ZnO‐nws/PEN‐Ph crosslinked composite films are endowed with excellent thermo‐stability and operating temperature. With the ZnO‐nws incorporated, the dielectric constant of the composite is improved from 3.4 to 6.2 at 1 kHz when the ZnO‐nws weight content is 16 wt%. The mechanical property test shows that the tensile strength increases with the increasing weight content of ZnO‐nws. The cross‐sectional micromorphology of the composites is determined by SEM and it shows that the ZnO‐nws is uniformly dispersed in PEN‐Ph matrix. These results indicate that the ZnO‐nws act both as catalyst and reinforce element for PEN‐Ph to obtain high performance crosslinked composite films. POLYM. COMPOS., 39:2801–2811, 2018. © 2016 Society of Plastics Engineers