Tunable oriented cellulose/BNNSs films designed for high-performance thermal management

In the thermal management application, polymeric composites with highly thermal conductivity are developmentally limited. It is mainly caused by the unsatisfactory situation of effective structure research on thermal conductivity enhancement in polymeric composites. In this work, a multi-orientation structure in cellulose/BNNSs (CBN) composite with alignment of cellulose nanofibers and BN nanofillers was fabricated by a tunable orientation strategy strain-inducing and post-pressing method. The as-prepared CBN20-3 films (with 20 wt% BN content and draw ratio of 3) exhibit superior thermal conductivity (40.23 W·m−1·K−1), excellent mechanical properties (tensile strength up to 188.71 MPa), and thermal transfer capability (△T = 19.9 °C). The obtained CBN films exhibited a stepwise reinforced thermal conductivity and mechanical performance, and a synergistic orientation effect of cellulose after combined with BN nanosheets was observed. We believe that the multi-orientation strategy is generalizable in multifunctional composites, and the composite has great application potential in the field of thermal management of electronic devices.