Preparation And Properties Of Epoxy Composites With High Thermal Conductivity And Insulation

As a kind of important thermal management materials, thermal insulation composites are widelyused in the fields of electronic packaging. It is the key to improve thermal conductivity of thermallyconductive insulation composite materials, which ensures the functionality of various electroniccomponents and provides itself a better application prospect.In this study, high thermal conductivity and insulating epoxy resin matrix composites wereprepared by the mixture of epoxy resin matrix and thermally conductive fillers, including hexagonalboron nitride (h-BN), aluminum nitride (AlN) and cubic boron nitride (c-BN), by themulti-component and high filler content addition. The composite materials were characterized byusing XRD、TG、FI-IR、SEM in order to figure out the influence of fillers types, content andingredient distribution ratio on the thermal conductivity and mechanical properties of preparedthermally conductive insulation composite materials.It was found that the increase of composites thermal conductivity predominatly depending on theincreasing of fillers content. The coarse hexagonal boron nitride (h-BN), which had a high thermalconductivity, good wettability and good compatibility with small granules, presented the best thermaleffect through forming more effective thermal conductive network. With the80wt%h-BN addtion, themaximum thermal conductivity of composite materials was achived as2.864W/m·K. Furthermore,pre-treatment of silence coupling agent could effectively reduce the interface thermal resistancebetween matrix and filler and therefore improve the thermal conductivity of composite materials.The mechanical property tests indicated that the impact resiatance of composites, although withdifferent types of filler, increased first and then decreased with filler addtion, and the maximum ofimpact strength was achieved at the filler content of60wt%. Moerover, the hexagonal boron nitride(h-BN) addtion presented the best impact resistance among the composites with different fillers.Above results suggested that, within a certain filler content range, the filler particles could effectivelypinned microcrack and suppressed the generation of cracks; with the increasing of the fillers content,the particles agglomeration, gaps, holes and other defects increased, so the impact resistance of thecomposite materials started to decline.The dielectric properties of the composite materials were found decreased with the increasingfillers content, fortunately the values were big enough for ensuring a good insulation. When the fillerscontent was up to80wt%, the permittivity was still less than5.5, which can meet the material insulation performance requirements. The TG analysis of the composite materials showed that thedecomposition tempaeratures of composites increased with the increasing filler content, whichindicating an enhanced thermal stability.