The Preparation And Dielectrical Properties Study Of Polymer Nanocomposites With High Diedlectric Constant And High Breakdown Strength

With the development of electronic and electrical industry,electrical components,as an important device,play a vital role in the development of electronic and electrical industry.As an important part of electrical components,capacitors are widely used in electronic,aerospace,communications and other fields.In order to adapt to the development of the times,capacitors are developing towards miniaturization and lightweight to meet the actual needs of production and life.In order to meet the requirements,we need to prepare dielectric materials with high dielectric properties,low loss characteristics and good processing performance.Traditional dielectric materials have good dielectric properties,but they have poor processing performance.Therefore,we compound inorganic materials with polymer composites to prepare polymer-based nanocrystalline dielectric materials.It has good processing properties.and improves the overall dielectric properties by using the dielectric properties of inorganic materials.However,there are still many problems in the current research process,such as the influence of the morphology and dispersion of inorganic nano-filler,the compatibility of inorganic particles with polymer matrix,and the image of dielectric properties of inorganic particles and so on.In this paper,copper calcium titanate nanowires were prepared by hydrothermal method,and were coated with organic and inorganic materials to prepare copper calcium titanate / polyvinylidene fluoridehexafluoropropylene nanocomposites.The influence and improvement of the morphology and surface modification of copper calcium titanate on the dielectric properties of the composites were studied,and the composite materials were prepared by using different sizes gold nanoparticles with poly(methyl methacrylate).The effect of coulomb block effect on the dielectric properties and enhancement of composites was studied.In the first part,we synthesized the copper calcium titanate nanowires by a new method,and prepared the copper titanate calcium titanate nanowires/polyvinylidene fluoride hexafluoropropylene nanocomposites.Compared with the traditional copper calcium titanate/ polyvinylidene fluoride hexafluoropropylene nanocomposites,the effect of morphology on dielectric properties was studied.After that,the surface of copper calcium titanate was coated with organic materials such as tannic acid and the inorganic material alumina,and then the surface treated copper calcium titanate nanowires and nanoparticles were filled into polyvinylidene fluoride hexafluoropropylene matrix to preparate nanocomposites.By testing the morphology and dielectric properties of the composites,the results show that the dielectric properties of the composites with the copper calcium titanate nanowires are better than those with the copper calcium titanate nanoparticles.The composites have better dispersion after surface modification.Thus,the dielectric properties of the composites are improved.In the second part,we prepared two kinds of gold nanoparticles with different sizes and filled them into polymethyl methacrylate matrix.The surface of Au particles has been modified organically to make them have better dispersity in polymer matrix.It is found that the modified Au nanoparticles have good dispersion in the polymer group,and the breakdown strength of the composites are improved while the small size gold nanoparticles are more effective.Compared with two kinds of gold nanoparticles,the small size gold nanoparticles have higher dielectric constant and energy density while the large size gold nanoparticles are more effective in improving energy efficiency.