Polybenzimidazole thermal management composites containing functionalized boron nitride nanosheets and 2D transition metal carbide MXenes

Recently, polymer-based thermal management materials have been receiving more and more attention. Always, introducing the thermal conductive nanofillers to prepare polymer composites is one of the best ways to improve the thermal conductivity (TC) of the polymer. However, the simple and effective way to improve thermal conductivity by increasing fillers loading amount often brings the decrease of mechanical property resulted by agglomeration. Herein, we combined 2D transition metal carbides (Ti 3 C 2 T x ), and functionalized boron nitride nanosheets (f-BNNS) together for simultaneously enhancing the TC and mechanical property of polybenzimidazole (PBI)-based composites. As the loading amounts of f-BNNS-Ti 3 C 2 T x reached 25 wt% (f-BNNS: 12.5 wt%, Ti 3 C 2 T x : 12.5 wt%), the in-plane and through-plane TCs of the f-BNNS-Ti 3 C 2 T x /PBI composite film reach ~5.06 and ~3.44 W m −1  K −1 which are ~12.05 and ~8.19 times higher than those of neat PBI film. More notably, the synergistic effect of interspace-filling and bridging between f-BNNS and Ti 3 C 2 T x also prevents the agglomeration and facilitates the improvement of mechanical property, even at a high loading amount of 25 wt%, the yield and ultimate tensile strengths of f-BNNS-Ti 3 C 2 T x /PBI composite film are ~175.5 and ~189.6 MPa with increases of ~61.1% and ~39.8% compared to those of neat PBI.