| Polymer-based dielectric composites with good flexibility,excellent dielectric properties and convenient processing have been widely applied in the electrical and electronic fields.Currently,great majority of the polymer based dielectric composites are formed by thermal curing,which requires a large amount of organic solvents and is energy-intensive,and the surface of the cured film is easy to be rough.Compared with thermal curing,the technology of UV curing has great potential application in high-tech fields owing to its advantages of high-efficiency,energy saving and environmental protection.The main material for UV curing is photosensitive resin,but the dielectric constant of the photosensitive resin is uncontrollable and cannot meet the requirements of the high dielectric field,which limits the application of the UV curing technology in the preparation of the polymer-based dielectric materials.In this study,the common photosensitive resin epoxy acrylate was used as polymer matrix,inorganic particles alumina and barium titanate were used as fillers respectively,developing a photocuring system for polymer-based dielectric materials,a range of EA composites with adjustable dielectric constan were prepared.Clarifed the law of the influence of filler particle shapes,sizes and structures on the electrical properties of the material,hoping to provide reliable experimental data and theoretical references for 3D printed functionally graded polymer-based dielectric composites.The results are as follows:(1)The s-Al2O3/EA composites were frabriated by UV-cured epoxy acrylate,and the irregular alumina was used as a filler to frabriate i-Al2O3/EA composites as a comparison.The result demonstrated that the introduction of Al2O3 particles increased the relative permittivity and decreased the dielectric loss of composites.As the filling amount of Al2O3 is 50 vol%,the relative permittivity of i-Al2O3/EA and s-Al2O3/EA are 7.28 and 7.10 respecti-vely,and dielectric loss are 0.0099 and 0.012 at room temperature of 50 Hz.Furthermore,the breakdown strength of the i-Al2O3/EA composites were also higher than that of s-Al2O3/EA at the same filling volume fraction.(2)BT/EA composites were manufactured by UV curing,which filled with BT-30,BT-05 and BT-006,respectively,and investigated the effect of filler particle size on the electrical properties of the composite.It was found that as the volume ratio of BT increases,both the relative permittivity and dielectric loss of BT/EA increased.At room temperature of 50 Hz,as the filling amount of BT is 25 vol%,the relative permittivity of composite with BT-30,BT-05 and BT-006 were 21.5,24.1 and 17.7,respectively,which is 3.39,3.92 and 2.61 times higher than that of pure EA matrix,and the dielectric loss increased to 0.114,0.333 and 0.252.In addition,the composites for BT-05 showed superior resistance to breakdown performance.(3)The BT?Al2O3 nanoparticles with core-shell structure was synthesized by modifying BT-006 surface with precipitation method,and the BT?Al2O3/EA composites were prepared by UV curing.The relative permittivity and dielectric loss of BT@Al2O3/EA were reduced compared to before modification in some extent at the same volume ratio of fillers.As the filling amount of fillers is 25 vol%,the relative permittivity of BT@Al2O3/EA only increased to 14.5 at room temperature of 50 Hz,but it is still 1.97 times higher than that of pure EA,and the dielectric loss was 0.103,which is 59.1%lower than the BT-006/EA with the same volume ratio of filler.The breakdown test showed a significant increase in the breakdown strength of BT?Al2O3/EA composites.At the same time,the breakdown field of the modified composites has been significantly improved. |
PDF Full Text Request