Mass production of high thermal conductive boron nitride/nanofibrillated cellulose composite membranes

Boron nitride nanoplates (BNNPs) are highly desirable in thermal management applications. To achieve better performance, boron nitride (BN) has to be extensively exfoliated and dispersed in liquids. However, most of current techniques suffer from being high in cost, time consuming, and environmentally unfriendly, which limits the mass production of BNNPs for a wide range of applications. Herein, we demonstrate a simple yet green manufacturing process for efficient exfoliation and dispersion of BN and bamboo cellulose via stress-induced simultaneous exfoliation/dispersion (SISED) in an aqueous medium. This method can produce well exfoliated BNNPs/ nanofibrillated cellulose (NFC) with the average BNNPs thickness of 51 nm and NFC diameter of 43 nm after only 1.98 h treatment. Thanks to the excellent dispersion, heat-conducting and electric-insulating BNNPs/NFC nanocomposite membranes with an BNNPs content of 40 wt% are fabricated through vacuum-assisted filtration. The micro-structures of the membranes as well as their mechanical and thermal properties can be tailored by changing the refining time and the pan gap to meet different needs. The resultant membranes exhibit high mechanical properties with a tensile strength of 74.6 MPa and excellent thermal conductivity of 20.64 W m−1 K−1, suggesting their great potential in fabricating next-generation portable electronics.