High‐concentration polybenzimidazole‐assisted exfoliation of boron nitride nanoflakes for polymer composites

In this article, we present a facile method for fabricating high thermally conductive and high‐strength polybenzimidazole/boron nitride nanoflakes (BNNS) composites. In brief, based on the method of liquid‐phase exfoliation, the polybenzimidazole functionalized BNNS (f‐BNNS) were facile obtained by directly sonicating the bulk hexagonal boron nitride (h‐BN) flakes/dimethylsulfoxide dispersion in presence of polybenzimidazole. The yield concentration of exfoliated BNNS can facile reach a high concentration of ∼1.43 mg/mL after direct sonication of 10 h with assistance of polybenzimidazole. By means of solution casting, the obtained f‐BNNS/polybenzimidazole composite films shows higher thermally conductivity and mechanical property compared to that of hexagonal boron nitride/polybenzimidazole composites. With 20 wt% of f‐BNNS loading, the yield and ultimate tensile strengths of f‐BNNS/polybenzimidazole composite film can reach ∼225.7 and 252.6 MPa. When the loading of f‐BNNS is 30 wt%, the thermal conductivity of f‐BNNS/polybenzimidazole composites is ∼8.58 W/mK, 27.68 times higher than that of pure polybenzimidazole. POLYM. COMPOS., 39:4285–4297, 2018. © 2017 Society of Plastics Engineers