Preparation Of Graphene Oxide/Polyarylene Ether Nitrile Composite And Its Application In Film Capacitors

Since the 21st century,with increasing energy demand and low use efficiency of fossil fuels,as well as environmental pollution caused by fossil fuels,it is extremely urgent to improve energy efficiency and find new clean and efficient energy sources.Among the emerging energy sources,energy storage capacitors have the advantages of high energy storage density,fast charge and discharge speed,anti-circulation aging,high temperature and high pressure and other extreme environments and stable performance,in line with the requirements of energy utilization in the new era,in electric power and electronic systems.It plays an increasingly important role.With the development of materials science,there is still much room for development of energy storage capacitors.The key to improve energy storage characteristics is to develop dielectric materials with high energy storage density.Poly(arylene ether nitrile)is a special polymer material with excellent properties.Its excellent high thermal stability,mechanical properties,dielectric properties and breakdown strength meet the requirements of film capacitors in many aspects.Therefore,in order to expand the application of poly(arylene ether nitrile),the properties of poly(arylene ether nitrile)materials are optimized by physical and chemical methods to meet their applications in film capacitors.Firstly,the biphenyl type poly(arylene ether nitrile)was prepared by the reaction of2,6-dichlorobenzonitrile with biphenyldiphenol.The biphenyl type poly(arylene ether nitrile)was successfully synthesized by infrared test.Then,a poly(arylene ether nitrile)film was produced by a casting method.The obtained poly(arylene ether nitrile)film was tested with a polypropylene film and a polyvinylidene fluoride film.The glass transition temperature of poly(arylene ether nitrile)was 216℃ by DSC,and the decomposition temperature of poly(arylene ether nitrile)was about 520℃ in TGA test,which prove that the poly(arylene ether nitrile)has excellent thermal stability;the mechanical properties test results show that the tensile strength is 120 MPa,indicating that the poly(arylene ether nitrile)has excellent mechanical properties;the dielectric-frequency of the biphenyl type poly(arylene ether nitrile)film is studied by dielectric test.The poly(arylene ether nitrile)has a dielectric constant of about 4 at room temperature and about 8 at 220℃.The relationship with temperature and conductivity values demonstrates that poly(arylene ether nitrile)has good insulation and can be used over a wide frequency range(100 Hz-200 kHz)and a wide temperature range(20-220℃).The poly(arylene ether nitrile)has a breakdown strength of 240 kV/mm at room temperature and 150 kV/mm at 220°C.The breakdown performance test at different temperatures proves that the poly(arylene ether nitrile)film can still be used in film capacitors at higher temperatures.Secondly,due to the low energy storage density of poly(arylene ether nitrile)films,which is only 1 J/cm~3,the application in energy storage film capacitors is greatly limited.Therefore,we dope to improve the dielectric properties of poly(arylene ether nitriles).Graphene is an inorganic material with very excellent electrical conductivity,but its dispersibility in the polymer is very poor.It will affect the dielectric loss and mechanical properties of the polymer at a large filling content.Therefore,we use a coating method.The sulfonated poly(arylene ether nitrile)is attached to the surface of the graphene oxide,and then the poly(arylene ether nitrile)is filled with the coating to obtain a composite film having good compatibility.The prepared composite film was tested,and the results showed that the dielectric properties were greatly improved under the premise of ensuring mechanical properties and thermal properties,When the filler content reaches 10 wt%,the dielectric constant is increased to 20,and the storage density of the poly(arylene ether nitrile)composite is increased to 3.1 J/cm~3.Finally,in order to further increase the energy storage density of the material,we use a lamination process to increase the breakdown strength of the film.Due to process and environmental limitations,small pores and impurities are generated inside the film we prepare,and these pinholes and impurities seriously affect the breakdown strength of the film.Therefore,we use the pinhole shadowing effect to increase the breakdown strength of the films.When the number of layers of the composite material films reach to 4,the breakdown strength is as high as 270 kV/mm,and the storage density of the poly(arylene ether nitrile)film is successfully increased to 6.5 J/cm~3.Through the surface of this study,biphenyl poly(arylene ether nitrile)has excellent comprehensive performance and has great application potential in energy storage film capacitors.