Globular Flower-Like Reduced Graphene Oxide Design for Enhancing Thermally Conductive Properties of Silicone-Based Spherical Alumina Composites

Abstract

The enhancement of thermally conductive performances for lightweight thermal interface materials is a long-term effort. The superb micro-structures of the thermal conductivity enhancer have an important impact on increasing thermal conductivity and decreasing thermal resistance. Here, globular flower-like reduced graphene oxide (GFRGO) is designed by the self-assembly of reduced graphene oxide (RGO) sheets, under the assistance of a binder via the spray-assisted method for silicone-based spherical alumina (S-Al 2 O 3 ) composites. When the total filler content is fixed at 84 wt%, silicone-based S-Al 2 O 3 composites with 1 wt% of GFRGO exhibit a much more significant increase in thermal conductivity, reduction in thermal resistance and reinforcement in thermal management capability than that of without graphene. Meanwhile, GFRGO is obviously superior to that of their RGO counterparts. Compared with RGO sheets, GFRGO spheres which are well-distributed between the S-Al 2 O 3 fillers and well-dispersed in the matrix can build three-dimensional and isotropic thermally conductive networks more effectively with S-Al 2 O 3 in the matrix, and this minimizes the thermal boundary resistance among components, owning to its structural characteristics. As with RGO, the introduction of GFRGO is helpful when decreasing the density of silicone-based S-Al 2 O 3 composites. These attractive results suggest that the strategy opens new opportunities for fabricating practical, high-performance and light-weight filler-type thermal interface materials.The GFRGO was obtained by the spray-drying granulation technique, chemical pre-reduction and thermal annealing procedure. Firstly, 2 g GO were added into 1000 mL deionized water by ultrasonication for 180 min. Secondly, 0.4 g 5 wt% PVA aqueous solution was added drop wise into the dispersion, with magnetic stirring for 40 min at 65 • C. After that, the mixture was nebulized into small droplets under 150 • C by the spray dryer. The atomized droplets evaporated in a few seconds and converted into dried globular flower-like GO (GFGO) granules, with the help of the binder PVA. The dried GFGO powders were gathered in the collector. The sample was treated with 0.

Array Modified Molded Alumina Supported PdAg Catalyst for Selective Acetylene Hydrogenation: Intrinsic Kinetics Enhancement and Thermal Effect Optimization

“…The modified alumina powder still needs undergo the shaping process to obtain spherical alumina with a certain diameter. During the shaping process, the structure of the alumina powder will be further changed, which will greatly sacrifice the surface area and pore structure. , Therefore, it is desired to explore a novel method to fabricate molded spherical alumina with a largely improved surface area.…”