UV etched random copolymer membrane coated PBO fibers/cyanate ester wave-transparent laminated composites

Poly (p-phenylene-2,6-benzobisoxazole) fibers treated by random copolymer P(S-co-BCB-co-MMA) membrane and UV etching (UV-PBO@P fibers) are performed as reinforcement, bisphenol AF/amantadine modified bisphenol A cyanate ester (AEAF-co-BADCy) resin as polymeric matrix, and the UV-PBO@P fibers/AEAF-co-BADCy wave-transparent laminated composites were then fabricated. When the P(S-co-BCB-co-MMA) membrane thickness is 62.3 nm and the UV etching time is 96 h, UV-PBO@P fibers display the best interfacial compatibility with AEAF-co-BADCy resin, and the corresponding wave-transparent laminated composites present the optimal comprehensive performance. Interlaminar shear strength (ILSS) and flexural strength are 50.2 and 745.6 MPa, 27.4% and 21.6% higher than those (ILSS of 39.4 MPa, flexural strength of 613.3 MPa) of pristine PBO fibers/AEAF-co-BADCy wave-transparent laminated composites, respectively. And the composites possess low complex permittivity and tanδ, corresponding |T|² in the X band is 88.9–94.2%. High-frequency structural simulation (HFSS) results demonstrate that the radome from the composites displays high |T|² of 89.1–93.1% in the X-band, close to the theoretical calculation value. This work provides a certain theoretical guidance for fabricating lightweight, high strength, and high |T|² polymer matrix wave-transparent composites, and further broadens the application of PBO fibers and cyanate ester resins in aviation/aerospace, 5G communication services, electronic information, and other fields.