Globally enhanced thermal, mechanical and electrical properties of current-field grading composites with self-assembly semiconducting grains on 3D cellulose aerogel scaffolds

Polymeric materials doped with SiC particles can exhibit promising nonlinear properties that can be widely used in electrical field grading applications. However, excellent field-grading performance is at the expense of mechanical characteristics due to excess fillers in the composites. Therefore, how to realize synergistic optimization of electrical and mechanical performances in ultra-low SiC loading is urgent for practical applications. In this study, we report a novel strategy to achieve comprehensive enhancement of thermal, mechanical and electrical properties of epoxy composites with self-assembly surface-modified SiC particles on cellulose aerogel scaffolds. The composites exhibit excellent nonlinear electrical properties at a low SiC loading of 4.47 vol%, and introducing different volume fractions of SiC into cellulose aerogel supported epoxy composites can largely broaden the range of switching field. Meanwhile, the dynamic mechanical test reveals that the storage modulus and crosslinking density of the composites are markedly enhanced due to 3D interconnected structure, while the thermal conductivity of this composite is also notably improved by about 300%. This method provides a novel idea for electric field grading composites with concurrent reinforcement performances in potential applications.