Construction of fluorinated hyperbranched polyaryletherketone-based UV-cured films with low dielectric and enhanced mechanical properties

The incorporation of hyperbranched structure into the polyaryletherketone (PAEK) is a crucial method for achieving a low dielectric constant (Dk), and the inclusion of crosslinked structure effectively reduces the dielectric loss (Df). This approach is of great significance in the development of high-quality communication at high frequencies.However, it is still a significant challenge for maintaining its mechanical properties and reducing Dk and Df due to the poor film-forming properties and low ductility of hyperbranched polymers. In this study, we synthesized a novel acrylate-based fluorinated hyperbranched photosensitive polyaryletherketone (hb-P6FAEK-Ace) as a prepolymer with various bifunctional aliphatic active and 4-acryloyl morpholine as the reactive solvent. Upon UV irradiation, cured films were obtained. This method significantly improved the mechanical properties of the hyperbranched UV-cured resin, with the tensile strength of CF-DCDDA of 83.2 MPa and the elongation at break of 7.61%. Additionally, the five prepared photosensitive resins exhibited excellent rheological properties (from 71.6 mPa·s to 134.7 mPa s at 100 °C), rapid curing rates (within tens of seconds), and minimal volume shrinkage (<7%). Meanwhile, the Dk of CF-DCDDA was measured to be 2.87, with a Df of 0.0126 at the frequency of 20 GHz. This low dielectric expression for the crosslinked cured films could be ascribed to the confinement of electronic polarization caused by the crosslinked and hyperbranched structures. This work provides a simple, green, and promising strategy for enhancing the dielectric and mechanical properties of hb-PAEK.