Cyanate ester resins with superior dielectric, mechanical, and flame retardance properties obtained by introducing a fluorinated hyperbranched polyaryletherketone

Cyanate ester resins are broadly applied in electronic packaging, printed circuit boards, radomes, and communication satellites. Herein, a novel fluorinated hyperbranched polyaryletherketone (HBPAEK) with an epoxy terminal group was synthesized by one-pot polycondensation followed by terminal functionalization. Bisphenol A dicyanate ester resin modified with HBPAEK (m-BADCy resin) through a co-curing process demonstrated significantly improved wave-transparent performance, mechanical properties, thermal stability, and flame retardancy. The dielectric constant (ϵ) and dielectric loss tangent (tan δ) of m-BADCy resin modified with 20 wt% HBPAEK were reduced to 2.56 and 0.0084 from 3.02 and 0.0106 of the unmodified BADCy resin, respectively. The corresponding theoretical wave transmittance increased to 94.6% from 92.7%. In addition, the respective flexural and impact strength were improved dramatically to 140.3 MPa and 35.1 kJ m⁻² from 99.5 MPa and 11.8 kJ m⁻², respectively, increased by 41.0% and 197.5%. Besides, the m-BADCy resin exhibited remarkably improved flame retardancy with the UL-94 rate of V-0 and the LOI value of 37%, whereas the unmodified BADCy resin failed to pass the UL-94 test and showed the LOI value of 26%.