High Temperature Resistance And Wave Permeability Of Phthalocyanine Resin Composites Modified By Hollow Glass Microspheres

The high performance aerospace wave transmissibility material is the functional medium material to protect the aircraft to complete the detonation,communication and other tasks during the service process.The key dielectric constant of the wavetransmitting material should be less than 4 and the dielectric loss should be less than0.01.The complex thermal environment caused by friction with air in high speed flight determines that it should have excellent thermal stability and mechanical strength.In recent years,thermosetting resins with high temperature resistance,such as bismaleimide and cyanate ester,have been applied in the field of wave permeable materials.However,the usable temperature range of these materials is still below 400℃,and they cannot adapt to the external environment of aircraft at speeds above Mach4.To solve the above problems,we try to use a phthalonitrile resin matrix composite material to expand the temperature range of the resin based wave transmittance material.In this paper,phthalonitrile resin PN75 and its glass fiber cmposite material was modified by introducing hollow glass microspheres based on the wave transmittability and heat resistance of phthalonitrile resin.The specific research contents are as follows:(1)Hollow glass microspheres were introduced into PN75 resin by physical blending,and the structure and reaction of the monomer and the cured material were tracked by means of DSC and infrared spectroscopy.The machinability,wave permeability and particle dispersion of the cured material were analyzed by rotating rheology,resonant cavity method and scanning electron microscope.The results show that the processing window of the resin blends is shortened,the dielectric constant can be reduced to about 2.2,and the dielectric loss can be reduced to between 0.007-0.01.The wave transmissibility is improved remarkably.(2)On the basis of the above,insulating glass microspheres /PN75 matrix glass fiber composites were prepared,and the mechanical properties,heat resistance,saturated water absorption,dielectric properties and dynamic thermomechanical properties of the composites were analyzed.The results show that the composite with10% insulating glass microspheres formula has the best comprehensive properties.The dielectric constant of the composite can reach 2.8,the dielectric constant is less than0.007,the interlamellar shear strength is 34.3MPa,the bending strength is 371.6MPa,the 5% thermal decomposition temperature is 571.69℃ in the nitrogen environment,and the carbon residual rate is 86.084% at 800℃.Saturated water absorption rate 1.18%.The research shows that the introduction of insulating glass improves the wave permeability and heat resistance of the material.The composite material shows the stability of the dielectric constant in multi-frequency band,and the service temperature is above 400℃,which shows the possibility of it as a new wave permeability material.