Development of wave-transparent, light-weight composites combined with superior dielectric performance and desirable thermal stabilities

In this paper, a novel interfacial compatibilizer of soluble epoxy-terminated poly (p-phenylene-2, 6-benzobisoxazole) precursor (epoxy-prePBO) was synthesized to modify bisphenol A cyanate ester (BADCy) resin via copolymerization. Compared to PBO fibers/BADCy wave-transparent composites, the obtained PBO fibers/epoxy-prePBO modified BADCy (PBO fibers/PBO-co-BADCy) wave-transparent composite with 7 wt% epoxy-prePBO showed ultra-low dielectric constant (ε, 2.68) and dielectric loss tangent (tanδ, 0.0061) values, excellent mechanical properties (flexural strength, 658.5 MPa) and interlaminar shear strength (48.4 MPa), and outstanding thermal stability (THeat-resistance index, 262.9 °C). These properties proved its potential in applications, such as in radomes and antenna system of aircrafts.