Simultaneously enhancing the thermal conductivity and dielectric constant of BN/CF hybrid filled polypropylene/polystyrene composites via in situ reactive processing

Abstract Thermal conductive and electrical insulating polymer composites are exerted a tremendous fascination on the field of thermal management. The effective utilization of fillers is indispensable to construct the thermal conductive pathway to fabricate high thermal conductive polymer composites. Herein, a facile approach involves selective localization of boron nitride (BN) and carbon fiber (CF) through in situ polymerization of styrene through reactive processing as well as double‐percolation structure design. These composites can be easily fabricated by blending the BN, CF with polystyrene during the polymerization of styrene monomer and secondary compounding with polypropylene (PP). The selective localization of BN and CF was observed by scanning electron microscope (SEM) characterization. The cocontinuous structure of PP/PS was also confirmed by SEM observation. The thermal conductivity values was promoted from 0.22 W/mk for PP/PS blends to 0.62 W/mk for the in situ reactive blending composites with 14.5 wt% BN and 18 wt% CF. Moreover, the dielectric properties were also higher than that of the simple melt blending composites. Therefore, the method we proposed provides a potentially feasible plan to design and prepare the thermal conductive and electrical insulating composites for thermal management applications.