Polysilsesquioxane-PBO Wave-Transparent Composite Paper with Excellent Mechanical Properties and Ultraviolet Aging Resistance

The rapid development of radar antenna systems to meet requirements for high integration and precision places stringent requirements on the dielectric properties, mechanical properties and heat resistance of wave-transparent composite paper. In this paper, poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers are first dissolved by trifluoroacetic acid/methyl sulfonic acid to obtain PBO nanofibers (PNF), and the amino polysilsesquioxane (NH₂-POSS) is dispersed uniformly inside the PNF via ultrasonic-assisted and deprotonation. The POSS-PNF composite paper is fabricated by the method of “suction filtration and hot-pressing”. Because of the uniformly dispersion of NH₂-POSS, the POSS-PNF composite paper has a low dielectric constant (ε, 2.08) and dielectric loss tangent (tanδ, 0.0047), and the wave-transparent coefficient (|T|²) is 96.7% (1 MHz), which is higher than that of PNF paper (95.5%, 1 MHz). Additionally, the POSS-PNF composite paper possesses excellent tensile strength of 163.3 MPa, tensile modulus of 6.9 GPa, toughness of 9.1 MJ/m³, outstanding flame retardancy and excellent UV aging resistance. According to a simulation of the radome honeycomb panel, POSS-PNF composite paper has low loss and reflections of electromagnetic waves in the X-band (8.4 ~ 12.4 GHz), and wide angle of incidence (0°–80°), which favor high |T|². The results indicate that the POSS-PNF composite paper has excellent potential for applications in the fields of aerospace, wearable flexible electronic devices and 5G communication. Graphical Abstract: [Figure not available: see fulltext.].