Preparation and performances of novel polyphosphazene-based thermally conductive composites

Herein, we demonstrated poly(diaryloxy)phosphazene (PDPP) which has inherent thermal stability and flame retardancy, is used as a matrix material for the fabrication of novel thermal conductive composites (TCCs) with variety of thermal conductive fillers including aluminum oxide (Al2O3), boron nitride (BN), silicon carbide (SiC) and expended graphite (EG) with different particle size and volume fraction by special processing method. Thermogravimetric analysis (TGA) and limit oxygen index (LOI) results indicated that the TCCs own excellent thermal stability and flame retardancy. SEM analyses of the as-prepared materials showed high orientation degree of flake-like fillers after processing. The thermal conductivity (TC) of the TCCs measurements implied that the EG is the most effective filler to enhance the TC. TC measured in-plane direction reaches a highest value 7.05 Wm−1 K−1 for EG filled samples, which is times higher than PDPP matrix. This work explored a great potential of polyphosphazenes as a matrix material for TCCs.