Preparation And Dielectric Properties Of Fluorine-modified Polybutene-1 Films

With the rapid progress of science and technology,electronic devices are moving toward miniaturization,which will raise the requirements for the dielectric properties of electronic materials.The dielectric film with high dielectric constant is used as the dielectric of film capacitors,which can greatly increase the energy storage density.In order to better apply the film capacitor,it is necessary to conduct an in-depth study on the dielectric film.The BOPP film currently used frequently can no longer increase its energy-storage properties,so a new polymer film is needed to increase the storage density of the film capacitor.In this thesis,composite film was prepared by solution casting and melt blending,respectively,using C8 perfluoroacrylate and PVDF modified polybutene-1.The effects of some process parameters on the solution casting C8 perfluoroacrylate/polybutene-1 composite film and the effects of the two fillers on the modified composite film were studied,and the microstructure of the composite film was studied.The thermal properties,crystallization properties,dielectric properties and energy storage density are discussed.The main research contents are as follows:The C8 perfluoroacrylate/polybutene-1 composite film was prepared by the solution casting method,whose crystal form was not changed but crystallinity was slightly lowered.When the addition amount of C8 perfluoroacrylate was 0.1mass%,the dielectric constant of the composite film reached the maximum value of 12.85,and the dielectric loss of the film was not affected.The breakdown strength of the composite film was slightly increased and the energy-storage properties also increased.After soaking for 24 hours in anhydrous ethanol,the crystal form,crystallinity,breakdown field strength and dielectric loss of the composite film did not change,and only the dielectric constant decreased slightly.The crystal form of the composite film matrix crystallized by different solvents was I crystal form.The solvent with lower vapor pressure would reveal greater crystallinity of the composite film and larger dielectric constant,but the four solvents had no impact on the dielectric loss of composite film.The PVDF/PB-1 composite film was prepared by the solution casting method,which did not change the crystal form of the matrix PB-1,but decreased the crystallinity.When the PVDF content is 1mass%,the dielectric constant of the composite film reached the maximum of 10.89.Besides,the addition of PVDF did not affect the dielectric loss of the film,and would improve the storage density of the film.The C8 perfluoroacrylate/polybutene-1 composite film was prepared by melt blending.It was found that the crystal form of the composite film did not change,but the crystallinity decreased slightly.When the content of C8 perfluoroacrylate was 0.2mass%,the dielectric constant of the composite film reached 8.15,which was 3.7 times that of the pure PB-1 film.The dielectric loss of the composite film did not change.Both the breakdown field strength and the storage density increase.PVDF/PB-1 and PVDF/PB-g-MAH/PB-1 composite films were prepared by melt blending.It was found that the addition of PVDF and PB-g-MAH did not change the crystal of matrix PB-1 type,but reduced the crystallinity.The dielectric constant of the two composite films reached the maximum when adding 20mass% PVDF.Besides,the dielectric constant of the composite film added with PB-g-MAH was slightly increased because PB-g-MAH would improve the compatibility of PVDF and PB-1.The dielectric loss of the two composite films did not change and the energy storage density increased.