Study on modification of ZnNb2O6/PTFE microwave composites with LCP fiber

Abstract For polymer matrix microwave composites, the agglomeration of ceramic particles at a high filling ratio will cause the microwave dielectric properties, mechanical properties and thermal conductivity of the materials to deteriorate sharply. This paper examines the reinforcement effect of LCP A950 fibers on PTFE and ZnNb2O6/PTFE composites to prevent this phenomenon. SEM, DMA, and other analysis methods showed that the incorporation of a small amount of LCP can promote the crystallization of PTFE and the mechanical strength of composites. When the volume fraction of the ZnNb2O6/PTFE/LCP three-phase is 50/45/5, the composites have a medium dielectric constant ( e r = 6.46), extremely low loss ( t a n δ = 7.54 × 10−4) and a near-zero temperature coefficient of the dielectric constant ( τ e = +2.25 ppm/°C). Under the same conditions, the linear expansion coefficient of the material is 45.4 ppm/°C, which is 30.5% lower than that before doping with LCP, and the flexural strength is 37.8 MPa, which is an increase of 17% com、pared to the previous value. The LCP-reinforced composites have excellent overall properties, but when the LCP content is too high, its reinforcement effect on the composites is gradually weakened.