Graphene−Perfluoroalkoxy Nanocomposite with High Through-Plane Thermal Conductivity Fabricated by Hot-Pressing

Abstract

With the rapid development of electronics and portable devices, polymer nanocomposites with high through-plane thermal conductivity (TC) are urgently needed. In this work, we fabricated graphene nanosheets−perfluoroalkoxy (GNs−PFA) composite sheets with high through-plane TCs via hot-pressing followed by mechanical machining. When the GNs content exceeded 10 wt%, GNs were vertically aligned in the PFA matrix, and the through-plane TCs of nanocomposites were 10–15 times higher than their in-plane TCs. In particular, the composite with 30 wt% GNs exhibited a through-plane TC of 25.57 W/(m·K), which was 9700% higher than that of pure PFA. The composite with 30 wt% GNs was attached to the surface of a high-power light-emitting diode (LED) to assess its heat-dissipation capability. The composite with vertically aligned GNs lowered the LED surface temperature by approximately 16 °C compared with pure PFA. Our facile, low-cost method allows for the large-scale production of GNs–PFA nanocomposites with high through-plane TCs, which can be used in various thermal-management applications.

Significantly Enhancing Mechanical and Thermal Properties of Cellulose-Based Composites by Adding Small Amounts of Lysozyme-Modified Graphene Nanoplatelets via Forming Strong Double-Cross-Linked Interface Interactions

“…We also found that during hydrogel molding, the surface tension and the sheet structure of composites made LmGNP tend to be horizontally distributed. Furthermore, the hot-pressing process enhanced the horizontal orientation of LmGNP, which built thermally conductive paths in the horizontal direction . It is worth noting that a large amount of Li + existing in the LiOH/urea solution will also break hydrogen bonds between LmGNPs when adding LmGNP into dissolved cellulose, making the LmGNPs uniformly distributed in the solution, which eventually gives the composite a uniform internal structure.…”

“…Furthermore, the hot-pressing process enhanced the horizontal orientation of LmGNP, which built thermally conductive paths in the horizontal direction. 55 It is worth noting that a large amount of Li + existing in the LiOH/urea solution will also break hydrogen bonds between LmGNPs when adding LmGNP into dissolved cellulose, 56 making the LmGNPs uniformly distributed in the solution, which eventually gives the composite a uniform internal structure. This may possibly make the overall properties of the composites more stable and homogeneous.…”

Anisotropic Thermally Conductive Perfluoroalkoxy Composite with Low Dielectric Constant Fabricated by Aligning Boron Nitride Nanosheets via Hot Pressing

“…Afterwards, the BNNs–PFA slurry was dried at 120 °C for 24 h in a vacuum oven to remove the residual ethanol. The obtained BNNs–PFA powder was put into a mold and heated at 400 °C for 1 h. The molten BNNs–PFA sample was hot-pressed at 380 °C under a pressure of 15 MPa for 15 min, then cooled to room temperature under the ambient pressure to form bulk composites [28]. The properties of these composites were then examined.…”