Preparation Of Quartz Fibre Reinforced Polyetheretherketone Wave-Transparent Composites And Study Of Their Properties

With the rapid development of aerospace electronics,the performance requirements for antenna systems such as radar radomes on spacecraft are becoming increasingly demanding.The aircraft is usually used in extremely harsh environment such as high temperature and high field.In order to ensure the transmission of electromagnetic wave and ensure the normal communication of the antenna system,it is urgent to develop low dielectric constant（ε）,low dielectric loss（tanδ）,high temperature resistance,high wear resistance,excellent mechanical properties of the wave transmission composite material.Traditional resins,such as epoxy and phenolic,have poor high temperature resistance and are limited in the field of wave-permeable composites.Polyether ether ketone（PEEK）has excellent high temperature resistance,flexibility,wear resistance,low dielectric constant and dielectric loss and other outstanding advantages,and can still have excellent comprehensive performance in a wide temperature range and extreme conditions,so it has great development potential in the field of wave-permeable composite materials.Quartz fiber（QF）is often used as reinforcement for the preparation of high-performance wave-permeable composites because of its excellent high temperature resistance,ablative resistance,chemical stability and good mechanical properties,and its dielectric properties are the best among many fibers at present.In this paper,PEEK and QF were selected as the matrix and reinforcement of the wave permeable composite material,and the resin matrix and reinforcement fiber were modified to develop quartz fiber reinforced polyether ether ketone wave permeable composite material with excellent comprehensive properties.（1）Taking QF as the research object,a simple and efficient sizing coating method was adopted to modify the surface of QF with different concentrations of polyimide-silicon dioxide（PI-Si O₂）water-based sizing agent,so as to improve the poor interface performance between quartz fiber and polyether ether ketone resin matrix.PI and Si O₂ were successfully modified on the surface of quartz fiber by FT-IR,SEM,contact Angle tester and electronic single fiber strength tester.When the concentration of PI and Si O₂ in sizing agent is 1wt%and 1.5wt%,respectively,quartz fiber reinforced polyether ether ketone（PI-1.5%Si O₂@QF/PEEK）composite has the best comprehensive performance.Compared with ungrouted QF/PEEK,the interlaminar shear strength,bending strength and impact strength increased by 29.72%,43.27%and 67.60%,respectively.Wear rate decreased by 21.36%;The thermal decomposition temperature and the residual amount at 800℃increased by 6.54%and 10.03%.The dielectric property of PI-1.5%Si O₂@QF/PEEK composite is the best,the dielectric constant is reduced to 3.0,and the dielectric loss is less than 0.02.（2）Taking PEEK as the research object,the mechanical blending method was used to add different mass fractions of nano-Si C into the PEEK resin system,and then the composite QF/Si C-PEEK composite was prepared with quartz fiber.SEM and EDX images showed that Si C nanoparticles dispersed uniformly in PEEK matrix.When the nano-Si C was 5%in PEEK resin system,the composite performance of quartz fiber reinforced polyether ether ketone（QF/5%Si C-PEEK）was the best,and the interlamellar shear strength,bending strength and impact strength of QF/PEEK without nano-Si C filling were increased by 12.67%,17.71%and15.57%,respectively.Wear rate decreased by 24.01%;The thermal decomposition temperature and residual content at 800℃increased by 2.07%and 3.26%.The dielectric constant and dielectric loss of QF/Si C-PEEK composite increased with the increase of Si C content.The dielectric constant of QF/5%Si C-PEEK composite was around 3.35,and the dielectric loss was lower than 0.02,which still met the requirements of wave transmittance materials.（3）Taking QF and PEEK as the research object,based on the optimization of（1）and（2）,the composite sizing agent with 1wt%PI and 1.5wt%Si O₂ concentration on the surface of QF was firstly modified,and then 5%nano-Si C was added to the PEEK resin matrix for modification.Finally,P-QF/S-PEEK composite material was prepared by combining the treated fibers with resin.Compared with QF/PEEK,QF/S-PEEK（QF/5%Si C-PEEK in（2））and P-QF/PEEK（PI-1.5%Si O₂@QF/PEEK in（1））,the composite properties of P-QF/S-PEEK are more excellent.Compared with QF/S-PEEK,P-QF/S-PEEK increased the interlaminar shear strength,bending strength and impact strength by 37.16%,50.42%and 79.12%,respectively.Wear rate decreased by 29.75%;The thermal decomposition temperature and the residual amount at 800℃increased by 9.64%and 10.63%.The dielectric constant of P-QF/S-PEEK was around 3.25,higher than that of QF/PEEK and P-QF/PEEK,lower than that of QF/S-PEEK,and the dielectric loss was lower than 0.02,but it still met the requirements of wave transmittance materials.The above results show that the combination of nano-Si C and fiber surface modified PI-Si O₂sizing agent in the resin matrix has a synergistic enhancement effect,which further improves the comprehensive properties of quartz fiber reinforced polyether ether ketone composites.