Large-scale synthesis of hexagonal boron nitride nanosheets and their improvement in thermal properties of epoxy composites

In this study, we report a novel method to synthesize hexagonal boron nitride nanosheets (BNNSs) using a ball-milled mixture of ammonium fluoroborate and sodium borohydride as precursor, under an ammonia atmosphere. The detailed morphological and structural investigations of the BNNSs are carried out by means of scanning electron microscopy, transmission electron microscopy (TEM), and high-resolution TEM, and detailed formation process of the BNNSs is proposed. We further utilize the BNNSs and acid-treated BNNSs (ATBNNSs) as nanofillers to fabricate a series of epoxy nanocomposites and study their varied thermal properties. The results indicate that the surface treatment and different fractions of BNNSs can discriminatively influence the thermal properties of epoxy nanocomposites. We also estimate the thermal conductivity channel thresholds with different ATBNNSs and BNNSs fractions. Through this work, an understanding of the interface treatment and filler fraction effects on thermal properties of epoxy nanocomposites is obtained. POLYM. COMPOS., 35:1707–1715, 2014. © 2013 Society of Plastics Engineers