Ultralow dielectric, fluoride-containing cyanate ester resins with improved mechanical properties and high thermal and dimensional stabilities

Abstract

In this contribution, we present a new strategy for the fabrication of modified cyanate ester resins combined with ultralow dielectric properties, improved mechanical properties and high thermal and dimensional stabilities. The fluoride-containing compound 2-((3-(trifluoromethyl)phenoxy)methyl)oxirane (TFMPMO), synthesized from m-(trifluoromethyl)phenol (TFMP) and epichlorohydrin (ECH), was used to modify bisphenol A dicyanate ester (BADCy) resins via copolymerization reaction. The BADCy resin modified with 15 wt% TFMPMO presented ultralow dielectric constant (ε, 2.75) and dielectric loss tangent values (tan δ, 6.7 × 10⁻³), high mechanical properties (impact strength of 15.4 kJ m⁻² and flexural strength of 141.0 MPa), and superior thermal and dimensional stability (T_{Heat-resistance index} of 206 °C and coefficient of thermal expansion of 6.4 × 10⁻⁵), and it possesses great potential application in radomes and antenna systems of aircraft.