Preparation Of Boron Nitride Based Thermal Conductive Insulating Material And Its Properties

High precision and high integration is the development direction of electronic components and circuit that need to work under the conditions of high frequency and high power,which makes the power density of electronic equipment increase rapidly.Therefore,it highly requires the applied electronic packaging materials not only insulate but also efficiently heat-sinking capable.Polymer materials have received extensive attention in the field of electronic packaging because of its excellent properties,such as excellent insulation,chemical corrosion resistance,light weight,convenient processing,good mechanical properties and good fatigue resistance.However,due to the poor performance on thermal conductivity of pure polymer materials,the further development of pure polymer materials is limited in electronic packaging and device heat dissipation.Therefore,it is very urgent to prepare the thermal conductive insulating materials with high-performance and high-reliability for the rapid development of electronic industry.At present,it is an effective way to improve the thermal conductivity of polymer materials by adding inorganic fillers with high thermal conductivity to the matrix.Boron nitride(BN)is an inorganic non-metallic material with versatile extreme properties,such as high thermal conductivity and excellent insulation,which makes it one of the best candidates for inorganic fillers.Therefore,it is the aim of the present work to develop insulating polymer composites with high thermal conductivity prepared by using epoxy resin(EP)as matrix,hexagonal boron nitride(h-BN)and cubic boron nitride(c-BN)as thermal conductive fillers.Firstly,the surface modification of h-BN and c-BN was carried out by silane coupling agent to improve the dispersion of h-BN and c-BN in EP.And then,the EP composites based on h-BN and c-BN were prepared respectively.The fracture morphology and thermal conductivity were studied.It is found that h-BN could combine with the matrix very well and reduce thermal resistance,and then improve the thermal conductivity of the material after surface modification.Secondly,the h-BN/c-BN/EP composites were prepared by adding h-BN and c-BN with different particle sizes and shapes to EP.The synergistic hybrid effect of the addition of double fillers on the thermal properties of composites was discussed by the study of the fracture morphology and thermal conductivity of the composites.With the total filling amount of the thermal conductive of 6 volt%,the thermal conductivity of the composites was increased by 47.84%,82.8% and 116.14% compared with the original epoxy resin respectively.The thermal conductivity of h-BN/c-BN/EP composites is the highest,in which the content of h-BN is 4 vol%,and the content of c-BN is 2 vol%.When the total content is determined,the effect of two-component addition is much better than that of adding one of the thermal conductive fillers alone,which indicates that the random distribution of h-BN and c-BN in the matrix has a synergistic effect on the construction of the thermal conduction channel.Finally,the thermal properties of composites were further improved by using h-BN as thermal conductive filler and adding double fillers to EP.Au NPs/h-BN composites and Au NPs-h-BN/c-BN/EP composites were prepared and then the nature of Au NPs/h-BN composites was analyzed by TEM,and the internal fracture morphology of the prepared EP composites was analyzed as well,so was the thermal and electrical properties of the composites.With the addition of Au NPs,the thermal conductivity of 3 vol% h-BN/6 vol% c-BN/EP composites was increased from 166% to 237%,and then the thermal conductivity of Au NPs between h-BN/c-BN double fillers was discussed.The interfacial thermal resistance between fillers was reduced,the thermal conductivity of the composites was improved,and the insulation properties were maintained very well.