聚苯乙烯/六方氮化硼/氧化铝微波复合基板的制备与性能研究

Investigations on preparation and properties of polystyrene/hexagonal boron nitride/alumina microwave composite substrates

针对六方氮化硼(h-BN)在聚苯乙烯(PS)中定向分布难且高填充比例下分散不均匀的问题,提出了湿法分散后再热压成型的方法;以h-BN和Al 2O 3组成复合填料,制备了一系列PS基微波复合基板,解决了h-BN的定向排列和复合填料均匀分布的难题。研究结果表明:采用该方法制备的基板样品在复合填料体积填充比例达到60%时均具有高度致密、均匀分散的显微结构;随着复合填料中h-BN比例的增加,基板样品的密度、热膨胀系数、介电常数和介电损耗均逐渐降低,面内热导率显著增加。当h-BN和Al_(2)O_(3)的体积比为11∶1时,复合基板具有优异的综合性能:面内热导率高达13 W/(m·K),热膨胀系数为15×10^(-6)/K,介电常数为4.3,介电损耗为1.44×10^(-3)(@10 GHz),在5G/6G通讯领域具有良好的应用前景。

In order to obtain highly directional arrangement of hexagonal boron nitride(h-BN)in polystyrene(PS)and homogeneous dispersion under a high filling ratio,this work proposes a method of wet dispersion combined with hot pressing.A series of PS based microwave composite substrates are prepared with hybrid fillers of h-BN and Al 2O 3.The problems about alignment of h-BN and uniform distribution of hybrid fillers are solved effectively.The results illustrate that all the substrate samples prepared by this method show a highly dense and uniformly dispersed microstructure when the filling ratio of hybrid fillers reaches 60 vol%.With the increase of h-BN ratio,the density,thermal expansion coefficient,dielectric constant and dielectric loss of the substrate samples decrease gradually,and the in-plane thermal conductivity increases significantly.When the volume ratio of h-BN to Al_(2)O_(3)is 11∶1,composite substrates have excellent comprehensive properties:the in-plane thermal conductivity is up to 13 W/(m·K),thermal expansion coefficient is 15×10^(-6)K,dielectric constant is 4.3 and dielectric loss is 1.44×10^(-3)(@10 GHz),showing a good application prospect in the field of 5G/6G communication.