Ordered stacking of oriented BN in confined space to construct effective heat transfer pathways

Abstract

High orientation of thermally conductive fillers has been proved to improve thermal conductivity of polymer-matrix composites effectively. Thus, constructing effective heat transfer pathways of the oriented fillers is a key issue. In this work, the multilayered ribbon network was in-situ formed to confine the stack space of boron nitride (BN) platelets, which was beneficial to increase the local concentration of BN. Further, the ordered stacking of oriented BN was constructed in confined 2D space during the multistage stretching extrusion, and then effective heat transfer pathways of the oriented BN were achieved. Meanwhile, the multilayered ribbon network could improve the strength and toughness of thermally conductive composites, simultaneously. Consequently, in-plane thermal conductivity, yield strength and impact strength of the obtained composite with the multilayered ribbon network at 30 wt % BN were 319%, 60% and 160% higher than those of the traditional compression molding composites, respectively. Therefore, this work offers a new method for the construction of effective heat transfer pathways in polymer-matrix composites to achieve both high thermal conductivity and good mechanical properties.