Preparation and properties of quartz fiber cloth/vinyl-containing polysilazane high temperature wave-penetrating composites

Based on the study of the basic properties of vinyl-containing polysilazane (PSN1) resin, a polysilazane-based high-temperature wave-penetrating composite quartz fiber/PSN1(QF/PSN1) was fabricated by laminated pressing method using quartz fiber cloth as the reinforcing material. The mechanical properties and dielectric properties of the QF/PSN1 composites at room and high temperature were investigated. The results show that PSN1 resin has excellent processing ability with viscosity lower than 1 Pas between 60℃ and 151℃, and low curing temperature less than 200℃. The cured PSN1 resin exhibits high thermal stability T_5% (the temperature at which the mass of the resin lost 5%) above 480℃ and W_R (the mass residual fraction) above 76% at 800℃ in both N₂ and air atmosphere. The flexural strength and interlaminate shear strength (ILSS) of QF/PSN1 composites show a trend of decreasing first and then increasing with the rising of temperature. And the flexural strength is more than 120 MPa after holding for 10 min at 450℃, which demonstrates that the QF/PSN1 composites possess excellent mechanical properties. QF/PSN1 composites show superior dielectric properties with dielectric constant (ε) lower than 3.2 and dielectric loss (tanδ) all less than 0.01 from room temperature to 450℃ in the frequency range of 1~12 GHz. The above studies indicate that PSN1 resin has high potentials as a new type of resin matrix for the high-temperature wave-penetrating composites.