Study On The Preparation And Properties Of 3D-BNNS/Silicon Modified Epoxy Resin High Thermal Conductivity Composite

As a promising functional materialthermal conductive polymer matrix composites play an increasingly important role in many fields such as microelectronics,aerospace,electronic information and electrical insulation.Because of its excellent electrical insulation,adhesion,thermal and mechanical properties,epoxy resin has many advantages,such as simple molding process,low cost and so on.So far it is still the first choice for electrical and electrical equipment and microelectronic packaging.Boron nitride?BN?has unique electrical insulating properties,excellent thermal conductivity and chemical stability,ultra-low dielectric constant and thermal expansion coefficient.It is an ideal thermal conductive filler.In this paper,six boron nitride is used as raw material.The six boron nitride is treated by surface treatment.Then,boron nitride nanosheets are prepared by ultrasonic degradation.BNNS/PAA hydrogels were prepared from six square boron nitride and polyacrylic acid,and 3D-BNNS aerogels were prepared by freeze-drying technology.Organosilicon modified epoxy resin was immersed in3D-BNNS aerogel by vacuum impregnation prepared silicon modified epoxy resin based thermal conductive composites.By using Fourier transform infrared spectroscopy?FTIR?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X ray diffraction?XRD?on after separation of boron nitride and boron nitride aerogels were characterized by thermal mechanical analyzer,and the composite mechanical properties,electrical properties,thermal conductivity of comparative test analysis.The results show that the effect of six square boron nitride after the modification is obvious,and the yield is 3.3 times higher than that before the modification,and the peeling time is shortened.With the increase of boron nitride content,the specific surface area and pore size of the prepared boron nitride nanoscale aerogels decrease.The thermal stability of the epoxy resin modified by organosilicon is better than that of the original epoxy resin.When the mass ratio of organosilicon to epoxy resin is 2:3 and the reaction time is 2hours at 180?,the thermal stability of the silicone epoxy resin is the best.When the amount of BNNS is 6wt%,the impact strength of epoxy composites is2.466KJ/m²,which is 34%higher than that of original silicone modified epoxy resin.When the content of BNNS is 8wt%,the flexural strength of the composite is 126.2MPa,which is 11%higher than that of the original organosilicon modified epoxy resin.The relative dielectric constant of the composites in the three-dimensional network structure system is low,and can still be kept below5.5 when the filling is filled.With the increase of boron nitride nanosheets,the dielectric loss increases,and the volume resistance and surface resistance change little.When the content of boron nitride nanoscale is 6wt%,the breakdown field strength of the composite material reaches the maximum value of 21.5kV/mm.With the increase of six boron nitride content,the thermal conductivity of composites increases gradually.When the content of boron nitride is 10wt%,the thermal conductivity of composites is 1.68W/mK.,which is 8.6 times that of pure epoxy resin and 6.2 times of epoxy resin/BNNS.3D-BNNS/SiEP increases the thermal conductivity relatively faster with the increase of temperature.The thermal conductivity of 3D-BNNS/SiEP reached 2.03W m^-1K^-1 when temperature is 125?,The thermal conductivity is 21%higher than that at room temperature.