Improved thermal conductivity of polypropylene filled with exfoliated hexagonal boron nitride (hBN) particles

In this work, we show the route to obtain thermoplastic based composites with an enhanced thermal conductivity that was achieved by using exfoliated hexagonal boron nitride (hBN) particles as a filler material. Reports on composites with bulk or nano hBN showed, that while increasing the filler load improves thermal properties it could aggravate the composite melt rheology and mechanical properties. On the other hand, exfoliated hBN particles compared to bulk or nanopowder hBN could provide even better thermal properties with no degradation in composite mechanics, which was shown for epoxy. Taking into account the above, we obtained exfoliated hBN particles by ultrasound treatment in isopropyl alcohol and then used them as a filler in polypropylene based composites to increase the thermal conductivity. The composites with 29% wt. of exfoliated hBN showed a thermal conductivity of 0.721 W m(-1) K-1 which is 4 times higher than for pristine polypropylene.