Thermally Annealed Anisotropic Graphene Aerogels and Their Electrically Conductive Epoxy Composites with Excellent Electromagnetic Interference Shielding Efficiencies

Authors:
  • XLXing-Hua Li
    Xing-Hua Li
  • XLXiaofeng Li
    Xiaofeng Li
  • KLKai-Ning Liao
    Kai-Ning Liao
  • PMPeng Min
    Peng Min
  • TLTao Liu
    Tao Liu
  • ZYZhong-Zhen Yu
    Zhong-Zhen Yu
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Abstract
Dispersion and spatial distribution of graphene sheets play crucial roles in tailoring mechanical and functional properties of their polymer composites. Anisotropic graphene aerogels (AGAs) with highly aligned graphene networks are prepared by a directional-freezing followed by freeze-drying process and exhibit different microstructures and performances along the axial (freezing direction) and radial (perpendicular to the axial direction) directions. Thermal annealing at 1300 oC significantly enhances the quality of both AGAs and conventional graphene aerogels (GAs). The aligned graphene/epoxy composites show highly anisotropic mechanical and electrical properties and excellent electromagnetic interference (EMI) shielding efficiencies at very low graphene loadings. Compared to the epoxy composite with 0.8 wt% thermally annealed GAs (TGAs) with an EMI shielding effectiveness of 27 dB, the aligned graphene/epoxy composite with 0.8 wt% thermally treated AGAs (TAGAs) has an enhanced EMI shielding effectiveness of 32 dB along the radial direction with a slightly decreased shielding effectiveness of 25 dB along the axial direction. With 0.2 wt% of TAGA, its epoxy composite exhibits a shielding effectiveness of 25 dB along the radial direction, which meets the requirement of ~20 dB for practical EMI shielding applications.
Funding Information
  • Ministry of Education of the People's Republic of China (YS201402)
  • Ministry of Science and Technology of the People's Republic of China (2016YFC0801302)
  • National Natural Science Foundation of China (51403016, 51521062, 51533001)

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