Highly Thermal Conductivities, Excellent Mechanical Robustness and Flexibility, and Outstanding Thermal Stabilities of Aramid Nanofiber Composite Papers with Nacre-Mimetic Layered Structures

Abstract

Aramid nanofiber (ANF) paper has shown potential applications in flexible electronics. However, its inherent low thermal conductivity coefficient (λ) values might threaten the safety of devices under a high-power working condition. In this work, polydopamine-functionalized boron nitride nanosheet (BNNS@PDA)/ANF thermally conductive composite papers with nacre-mimetic layered structures were prepared via highly efficient vacuum-assisted filtration followed by hot pressing. For a given BNNS loading, the surface functionalization of BNNS could further enhance the thermal conductivities and mechanical properties of BNNS@PDA/ANF composite papers. BNNS@PDA/ANF composite papers presented anisotropic thermal conductivities, and the through-plane (λ⊥) and in-plane (λ∥) values of the 50 wt % BNNS@PDA/ANF composite papers reached 0.62 and 3.94 W/mK, 181.8 and 196.2% higher than those of original ANF paper, respectively, which were also higher than those of 50 wt % BNNS/ANF composite papers (λ⊥ = 0.52 W/mK and λ∥ = 3.33 W/mK). The tensile strength of the 50 wt % BNNS@PDA/ANF composite papers reached 36.8 MPa, 30.5% higher than that of 50 wt % BNNS/ANF composite papers (28.2 MPa). In addition, the heat resistance index (T HRI) of the 50 wt % BNNS@PDA/ANF composite papers was further increased to 223.1 °C. Overall, our fabricated BNNS@PDA/ANF composite papers possess highly thermal conductivities, excellent mechanical robustness and flexibility, and outstanding thermal stabilities, showing great potential applications in the fields of intelligent wearable equipment, flexible supercapacitors, and flexible electronics.

Improving the thermal conductivity of epoxy composites using a combustion-synthesized aggregated β-Si3N4 filler with randomly oriented grains

“…BN possesses a hexagonal crystal structure and exhibits a layerlike structure with a high aspect ratio. Such morphology makes it difficult to obtain a uniform dispersion of BN grains in a composite material, and the resulting composite loaded with BN tends to have an anisotropic thermal conductivity owing to its high aspect ratio [11][12][13][14] . AlN and Si 3 N 4 are easily available commercially compared to BN.…”

3D Shapeable, Superior Electrically Conductive Cellulose Nanofibers/Ti 3 C 2 T x MXene Aerogels/Epoxy Nanocomposites for Promising EMI Shielding

“…As a degradable nanomaterial with abundant source, CNF is a promising green material owing to its good biocompatibility, excellent mechanical properties, and low density and has broad application prospects in EMI shielding, energy storage, battery applications, etc. [33][34][35][36]. In this work, CNF is assembled with Ti 3 C 2 T x nanosheets by hydrogen bonding, followed by directional freezing and freeze-drying technique, in order to obtain the CNF/Ti 3 C 2 T x aerogel (CTA).…”

In situ molten phase-assisted self-healing for maintaining fiber morphology during conversion from melamine diborate to boron nitride

“…As typical BN materials, BN bers similar to anisotropic BNNSs enjoy wide attention owing to their unique properties provided by their high-aspect-ratio morphology. 5,6 Up to now, numerous fabrication techniques have been developed for the high-efficiency production of BN bers, which are mostly based on the spinning process that requires strict manipulations. [7][8][9][10][11] In addition, the pyrolysis of a C 3 N 6 H 6 $2H 3 -BO 3 (M$2B) supra-molecule adduct is an alternative way and promising for large-scale production owing to the facile and eco-friendly fabrication of M$2B.…”

“…[7][8][9][10][11] In addition, the pyrolysis of a C 3 N 6 H 6 $2H 3 -BO 3 (M$2B) supra-molecule adduct is an alternative way and promising for large-scale production owing to the facile and eco-friendly fabrication of M$2B. [12][13][14] Unfortunately, the ceramic yield of M$2B is much lower ($20 wt%) than that of other reported polymeric precursors of BN, [15][16][17][18] for example, 57 wt% yield of poly [2,4,6-tris(iso-propylamino)borazine]. 17 This implies that substantial release occurs during thermal conversion from M$2B to the nal BN bers.…”