Comprehensive Performance of High-Temperature-Resistant and Low-Dielectric-Coefficient Phthalonitrile Resin

The shortcomings of the resin matrix often limit the application of composite materials in advanced equipment. The scope of use of phthalonitrile resins as composite matrices needs to consider factors such as the mechanical defects of the material, which can be called "Cannikin's Law" of phthalonitrile resins. "Cannikin's Law" of materials has garnered significant attention, and resin matrices with excellent mechanical properties, high heat resistances, and multifunctionalities are in demand in the aerospace field. Herein, we report a molecular modification design of high-temperature-resistant phthalonitrile resins modified by customized polyarylene ether nitrile fillers, which optimize the comprehensive performance of phthalonitrile resins from multiple perspectives. Specifically, nitrile groups are introduced into polyarylene ether nitrile and subjected to silicon hybridization, leading to the formation of a silicon ether-containing poly(arylene ether nitrile) oligomer (BPSiPEN); BPSiPEN is added to the phthalonitrile resins as a filler, and carbon fiber-reinforced phthalonitrile resin-based composites are prepared. The comprehensive performance of the modified composites with different additive amounts is systematically investigated and characterized. The results show that the introduction of BPSiPEN significantly improves the comprehensive performance of the phthalonitrile resin. Specifically, when 7% BPSiPEN is added, an ultralow dielectric coefficient, extremely smaller than those of other resins, is realized. The dielectric constant and loss are stabilized at 2.07 and 0.0058, which are 39.12 and 31.68% lower than those of the unmodified sample, respectively. The resin's high-temperature resistance and mechanical properties are also tested, and the dynamic mechanical properties, water absorption characteristics, and flame retardancy of the composites are analyzed.