Preparation And Properties Of Polymer-based Semiconductor Nanocomposite Dielectric Materials

Dielectric materials are important in electronic packaging,high voltage insulation and energy storage devices.Therefore,dielectric materials have been attracted much research interests.Although energy storage behavior and dielectric properties of various materials have been intensively investigated,there still many problems to be solved in the field of polymer-based composites.For example,as the incorporation of filler in the matrix is high,dielectric loss is too large,and the breakdown strength of the composites will decline rapidly.In this thesis work,composites with excellent dielectric property and energy storage were fabricated,and the effects of interface structure on breakdown strength were discussed.The effects of semiconductor filler on dielectric,breakdown,energy storage and thermal conductivity were systematically investigated.Based on the above results,polymer-based composite with suppressed loss and high breakdown strength were designed.First,in order to improve the dielectric and energy storage properties of the composites,nano-Zn O and Zn S were selected in the work,and then mixed with polyvinylidene fluoride(PVDF)to obtain the polymer composites with high dielectric and high energy storage.A series of samples were studied on dielectric,breakdown strength,energy storage,thermal conductivity and so forth.The result showed that with the increase of filler content,the dielectric properties were improved,as well as the energy storage density and breakdown strength with relatively low filler loadings.Based on the above results,Zn O-Zn S nanoparticles were prepared,and three-phase composites with polyvinylidene fluoride were obtained.The results showed that with the increase of the filler,the dielectric loss of the composite was effectively suppressed,and the breakdown strength still maintained high when the fillers were incorporated to the polymer matrix-with high loading.Compared with the same content of Zn S and Zn O,the energy storage density and breakdown strength of the three-phase composites have been both significantly improved.