Tuning high-temperature dielectric properties of poly ether ether ketone by using self-crosslinkable polyetherimide and nanoparticles

Polymer dielectric materials operating at high temperatures are widely needed for advanced electrical and electronic systems. However, currently commercial polymer dielectrics are limited to relatively low operating temperatures. Here, a series of polyether ether ketone (PEEK)-based blends with self-crosslinkable polyetherimide (c-PEI) has been prepared as high temperature dielectrics by melt blending. The obtained polymer blends maintain stable dielectric properties over a wide frequency and temperature range. At 160 °C，the dissipation factor of the blend film is only 0.0019 which is only 14% of the pristine PEEK. Crosslinked networks in polymer blends could efficiently restrict the movement of polymer segments which suppress the dielectric loss and enhance high temperature performance. Furthermore, the introducing of Al2O3 improve the dielectric constant of the polymer blend, which compensated for the decreased dielectric constant due to crosslinking. In addition, the c-PEI/PEEK blends could be produced by industrial-grade continuous production process. This work presents a feasible strategy to large-scale fabrication of high-temperature dielectric materials by melt blending with self-crosslinkable polymers.