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摘要
Polymeric materials doped with SiC particles can exhibit promising nonlinear properties which 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 nonlinear conductive and mechanical performances in ultra-low SiC loading is important for practical applications. In this work, SiC was modified by silane coupling agent, and then self-assembled on cellulose aerogels. The nonlinear conductive epoxy composite was prepared by a vacuum-assisted impregnation method, and the synergistic improvement of thermal conductivity, mechanical properties and nonlinear conductance properties was achieved. The results indicate that the composites exhibit excellent nonlinear conductive properties at a low SiC loading of 4.47%, and introducing different volume fractions of SiC into cellulose aerogel supported epoxy composites can largely broaden the range of switching field. In the condition of 10.58% loading, the composite possesses a switching field of 2.49 kV/mm and a nonlinear coefficient of 4.54. Meanwhile, the thermal conductive properties and dynamic mechanical tests reveal that the storage modulus is increased by about 100%, the cross-linking density is as high as 15.9×10?3 mol/cm3, and the thermal conductivity is increased to 0.69 W/(m·K) due to interconnected 3D structure. This method provides a new idea for the preparation of field-grading composites with excellent thermodynamic properties. ? 2023 Science Press.
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