Study On Preparation And Dielectric Energy Storage Of Barium Titanate Nanoparticles/Polyethersulfone Composites

With the development of the semiconductor industry,industries such as information and electronic electricity benefit a lot,the corresponding electrical and electronic products also show a smaller,more intelligent development trend.In order to follow this future development trend,the energy-storage capacitors are also moving toward the direction of high energy density and high storage efficiency.The energy-storage polymer-based nano-ceramics composites with low dielectric loss,high breakdown strength,high dielectric constant and easy processing have attracted a lot of attention.In this paper,polymer polyethersulfone(PES)with heat-resistant performance was used as the matrix of the composite materials,and barium titanate nanoparticles were used as filler to prepare the dielectric energy-storage materials with heat-resistant performance.By using small molecular phthalocyanine and hyperbranched phthalocyanine,the surface of the barium titanate nanoparticles was chemically modified.On the one hand,the interaction between barium titanate nanoparticles and polyethersulfone was enhanced according to similar dissolve mutually theory,and the defects(owing to the discontinuity of the interface)between barium titanate nanoparticles and polymer were reduced,and then the dispersibility of barium titanate nanoparticles in the matrix was increased.On the other hand,as the modified groups,the organic semiconductor material(phthalocyanine)with high dielectric constant can make the composite materials achieve good dielectric properties and high energy density under the lower filling.In the first part,barium titanate nanoparticles(about 100 nm in particle size)were used as filler,and the active cyano groups were introduced onto the surface of barium titanate nanoparticles by using hydrogen peroxide and 4-nitro-phthalonitrile.These steps provides the chemical basis for the subsequent situ phthalocyanine ring-forming reaction on the surface of barium titanate nanoparticles,and then the barium titanate nanoparticles covered by small molecular phthalocyanine with simple core-shell structure were synthesized.Finally,barium titanate nanoparticles coveredby the small molecular phthalocyanine were combined with the polyethersulfone matrix in the solution blending way to cast film.Compared with the barium titanate nanoparticles without modification,duo to the existence of organic phthalocyanine modified layer on the surface of barium titanate nanoparticles,the BT-CuPc/PES composites have good dielectric properties at lower loading.At the same time,the introduction of phthalocyanine modified layer also enhanced the interaction between barium titanate nanoparticles and polyethersulfone matrix,which resulted in significant dispersion of BT-CuPc nanoparticles in the matrix and improved breakdown strength and energy storage properties of the composites.In the second part,barium titanate nanoparticles with hyperbranched phthalocyanine(BT-HCuPc)were prepared by chemically grafting a layer of hyperbranched phthalocyanine polymer on the surface of barium titanate nanoparticles and then were combined with the polyethersulfone matrix to form polymer nanocomposites.The microstructure structure and the dielectric response of the polymer nanocomposites were analyzed effectively.The results showed that,compared with BT-CuPc,the hyperbranched phthalocyanine polymer can form more stable,comprehensive and dense cladding on the surface of barium titanate nanoparticles,which can further improve the dispersibility of barium titanate nanoparticles in the matrix.Basis on the similar dissolve mutually theory the interface interaction between barium titanate nanoparticles and the matrix is remarkably enhanced.Hence,the BT-HCuPc/PES polymer nanocomposites possess higher breakdown strength and maximum energy storage density.Especially,the lowest breakdown strength of composite material is 110 MV/m at the high temperature of150 ?.When the volume fraction of barium titanate is 30 vol%,the maximum energy storage density of BT-HCuPc/PES composites can reach 1.88 J/cm3 at 25 ? and 1.16J/cm3 at the high temperature of 150 ?,respectively,which is much higher than that of pure polyethersulfone matrix and BT/PES,BT-CuPc/PES composites.