A bio-based low dielectric polymer at high frequency derived from paeonol

A fluorinated monomer with crosslinkable benzocyclobutene groups has been successfully synthesized starting from bio-based paeonol through the Suzuki and Grignard reaction. Treating this monomer at high temperature forms a cross-linked resin (cured PFB), which exhibits high glass transition temperature (T_g) of 439 °C, low coefficient of thermal expansion (CTE) of 87.4 ppm/°C, low dielectric constant (D_k) of 2.62, and low dielectric loss (D_f) of 8.45 × 10^-4 at a frequency of 10 GHz. In particular, cured PFB displays low water uptake of 0.1% even immersing it in boiling water for 96 h. These results demonstrate that the fluorinated bio-based monomer is a suitable precursor for the preparation of the low-dielectric packaging materials used in the microelectronic industry. Especially, this contribution provides a new way for the conversion of bio-based paeonol into the high-performance materials.