Enhanced through-plane thermal conductivity of paper-like cellulose film with treated hybrid fillers comprising boron nitride and aluminum nitride

Abstract

A one-step exfoliation and functionalization method using ball milling was employed to prepare an amine-group-treated hybrid filler (BA-NH2) comprising boron nitride (BN) and aluminum nitride (AlN). A thermal conductive film (CNF/BAH-NH2) was then fabricated using the hybrid filler (BA-NH2) and a cellulose nanofiber (CNF) matrix via vacuum filtration and hot-press processing. After treating the surfaces of each of the fillers, the hybrid filler exhibited better dispersion in the film matrix by hydrogen bonding interactions for improved interfacial adhesion between the filler and matrix. Moreover, the treated AlN particles deposited on the surface-treated BN assist in the formation of heat-transfer paths along the through-plane direction. Hence, the thermal conductivity increased from 0.5 W m−1 K−1 (neat CNF film) to 5.93 W m−1 K−1 (50 wt% filler loading), which was a 1092% enhancement compared with the neat CNF film, and the thermal stability was enhanced by 27% (62.5 °C). Moreover, favorable mechanical properties such as tensile stress of 35.93 MPa and elongation at break of 4.09% were observed for the film.