"Preparation and properties of graphene-nano-diamond hybrid/ silicone rubber composites"

Abstract

"It has been proved that adding a single type of thermal conductivity filler is challenging to achieve a high theoretical thermal conductivity value of polymer composites. However, adding mixed thermal conductive fillers of different shapes to the polymer matrix makes it easier to form a thermally conductive path or reduce the voids in the matrix［1］. Hence, the polymer composite material has better thermal conductivity than the single-shape thermal conductive filling material. In this work, a structurally stable graphene-nano-diamond hybrid (GND) is obtained by taking advantage of dopamine's adaptability to almost any expression. Graphene is a two-dimensional material, while nano-diamond is a zero-dimensional material. They can produce cooperative thermal conductivity when both are added to the polymer matrix simultaneously. Moreover, nano-diamond and silicone rubber (SR) can block the conductive path of graphene and prepare thermal-insulating SR composite mate-rials. As seen in Fig 1(a), the graphene is transparent with some folds on the surface. As shown in Fig 1 (b), (c) and (d), there are many small particles on the surface of graphene, which are nano-diamonds, indicating that the preparation of GND hybrid materials is successful. The nano-diamond is fully loaded on the surface when more graphene exists, shown in Fig 1 (b). When there is less graphene, some nano-diamond particles hang outside the graphene lamella and are scattered around the graphene, and the nano-diamond agglomeration is severe. As shown in Fig 2, the thermal conductivity of SR composites with GND of m(graphene)/m(nano-diamond) 0/1.00 added is unchanged with the temperature increase. However, the thermal conductivity of SR composites with GND of m(graphene)/m(nano-diamond) 0.17/1.00, 0.25/1.00, and 0.50/1.00 added increases with the increase in temperature. GND ［m(graphene)/m(nano-diamond) 0.25/1.00] / SR composite shows the most obvious increasing trend, and the thermal conductivity at 100 ℃ is 56% higher than that at 25 ℃. At 25, 50, 75, 100 ℃, the thermal conductivity of GND ［m(graphene)/m(nano-diamond) 0.25/1.00]/SR composite is increased by 20.5%, 32.6%, 52.8% and 79.2%, respectively, compared with GND［m(graphene)/m(nano-diamond) 0/1.00] / SR composite."

Keywords

• silicone rubber， graphene， nano diamond， thermal conductivity，