Study On Preparation And Properties Of Boron Nitride/Polybenzoxazine Composite

In recent years,microelectronic devices are developing rapidly towards miniaturization and integration,which leads to a large number of electronic components are concentrated in a small space and produce a large amount of heat.The heat generated by electronic devices cannot be dissipated in time,which inevitably leads to overheating of components and shortens the service life of electronic devices.Therefore,we need to develop polymer matrix composites with high electrical insulation and high thermal conductivity as electronic packaging materials to increase the service life of electronic equipment.Most polymer materials have good electrical insulation,resilience,chemical corrosion resistance and high temperature resistance,but the thermal conductivity of polymer materials is generally low,which limits its wide application in the field of microelectronics.Therefore,we need to take some measures to improve the thermal conductivity of polymer materials.At present,the most common method is to add a high thermal conductivity filler to the polymer material.Some ceramic material has good dielectric properties and high thermal conductivity,widely used for packing of polymer encapsulation materials,among them,the boron nitride(BN)as a kind of synthetic non oxide ceramics materials,has high thermal conductivity,low thermal expansion coefficient,high thermal shock and low dielectric constant and dielectric loss,is considered to be used to improve the thermal conductivity of polymer ideal filler[13-16].In addition,the thermal conductivity of polymer materials can be improved by adding different shapes and types of fillers to construct a heat conduction network in the polymer matrix.In this paper,BN and boron nitride whiskers(BNW)were modified by posisiloxane(POSS),and the BN/BNw/PBz composite was prepared by using polybenzoxazine(PBz)as matrix and modified BN and BNW as filler.The effects of the content of BN and BNW,modification and synergistic effect on the properties of PBz composite were studied.The results show that the thermal conductivity of PBz composites increases with the increase of filler content.When 25 wt%m-BN and 25 wt%m-BNw are filled at the same time,the thermal conductivity of PBz composite reaches 1.27 W/mK,which is 5.5 times that of PBz matrix.The dielectric constant(?)and dielectric loss(Tan ?)are 3.83 and 0.0078,respectively.The thermal degradation temperature at 30%weightlessness(T30)and thermal resistance index(THRI)were 557.72? and 242.26?,respectively,which were 58.84? and 17.8? higher than that of PBz matrix.The tensile strength was 47.71 MPa.Meanwhile,KH560 was used to modify BN and SiCw,and KH540 was used to modify MgO.Using KH540-MgO as crosslinking agent,KH560-BN and KH560-SiCw were connected together through an amide reaction to obtain BN-MgO-SiCw composite filler,which was then filled into the PBz matrix.The effect of the content and synergistic effect of BN-MgO-SiCw composite filler on the properties of PBz composites was studied.The results show that the thermal conductivity of PBz composites increases with the increase of filler amount.When the filling amount of BN-MgO-SiCw is 50wt%,the thermal conductivity of PBz composite reaches 1.41W/mK,which is 6 times that of pure PBz matrix.The ? and tan? value are 0.013 and 6.91,respectively.The T30 and THRI are 572.21? and 243.96?,respectively,which were 73.33? and 19.5? higher than that of PBz matrix.The tensile strength was 49.97MPa.In addition,KH560 was used to modify BN and KH792 was used to modify Cf.BN-Cf composite packing was obtained by the interaction between KH560 and KH792.BN-Cf/PBz composites were prepared by using PBz as matrix and BN-Cf as thermal conductivity filler.The effect of the content of BN-Cf composite filler and the synergistic effect on the properties of PBz composite was studied.The results show that the thermal conductivity of PBz composite increases with the increase of BN-Cf filling amount.When the filling amount of BN-Cf is 50wt%,the thermal conductivity of PBz composite reaches 1.41W/mK,which is 5.8 times that of PBZ matrix.The ? and tan?are 6.57 and 0.0083,respectively.T30 and THRI are 537.5? and 237.54?,respectively,38.62? and 13.08? higher than that of PBz matrix.The tensile strength is 50.64MPa.