Enhanced Thermal Conductivity of Polyimide Composites with Boron Nitride Nanosheets

Abstract

A strategy was reported to prepare boron nitride nanosheets (BNNSs) by a molten hydroxide assisted liquid exfoliation from hexagonal boron nitride (h-BN) powder. BNNSs with an average thickness of 3 nm were obtained by a facile, low-cost, and scalable exfoliation method. Highly thermally conductive polyimide (PI) composite films with BNNSs filler were prepared by solution-casting process. The in-plane thermal conductivity of PI composite films with 7 wt% BNNSs is up to 2.95 W/mK, which increased by 1,080% compared to the neat PI. In contrast, the out-of plane thermal conductivity of the composites is 0.44 W/mK, with an increase by only 76%. The high anisotropy of thermal conductivity was verified to be due to the high alignment of the BNNSs. The PI/BNNSs composite films are attractive for the thermal management applications in the field of next-generation electronic devices.

An overview of boron nitride based polymer nanocomposites

“…Solution‐casting process was used for the preparation of thermally conductive polyimide/BNNS composite films. [ 186 ] Figure 17(b) indicates the thermal conductivity of neat PI and PI composite films with 7 wt% BNNSs. They found that the in‐plane thermal conductivity was increased by 1,080% where as out‐of plane thermal conductivity was increased by only 76% compared to neat PI.…”

Enhancing thermal conductivity of polyimide composite film by electrostatic self-assembly and two-step synergism of Al2O3 microspheres and BN nanosheets

“…The nano-sized llers, especially for metal or carbon nanomaterials with excellent thermal conductivity, can generally achieve signicant enhancement at a low lling (<15 wt%). It is noteworthy that only 7 wt% BNNS fabricated by the efficient exfoliation of BN nanosheets increased the thermal conductivity by 1080%, 14 which is similar to the enhancing effect of the conventional BN of more than 30 wt%. Apparently, great attention has been paid to the synergism of the llers hybrid for further improvement of the thermal conductivity.…”

“…11,12 In recent years, in order to solve this contradiction, researchers have proposed four novel strategies. The rst is to design new thermally conductive llers, such as awless graphene, 13 exfoliated BN nanosheet (BNNS) 14 and BN nanotubes. 15 The second is to construct a three-dimensional thermally conductive network by a novel method, such as electrostatic spinning, 16 chemical vapor deposition (CVD), 17 template method, [18][19][20] freeze-drying method, 21 and segregated structure method.…”

Hexagonal and Cubic Boron Nitride in Bulk and Nanosized Forms and Their Capacitive Behavior

“…The c‐ BN, due to its hardness, can be used as an abrasive material. While the excellent electrical resistivity of and thermal conductivity of BN makes the use for heat spreaders, the exfoliated hexagonal nanosheets can enhance the thermal conductivity of polymer materials . Other scientific fields where h‐ BN‐based materials can be found involve electrochemistry, biosensing, and even antibacterial properties .…”