材料科学
聚酰亚胺
石墨烯
复合数
电磁屏蔽
复合材料
各向异性
热稳定性
图层(电子)
化学工程
纳米技术
光学
物理
工程类
作者
Zhi Yu,Tianwen Dai,Shuaiwei Yuan,Huawei Zou,Pengbo Liu
标识
DOI:10.1021/acsami.0c07122
摘要
Anisotropic polyimide (PI)/graphene composite aerogels were fabricated by unidirectional freezing. A poly(amic acid) (PAA) ammonium salt/graphene dispersion was first synthesized by mixing together PAA, H2O, triethylamine (TEA), and graphene and then was successively subjected to one-way freezing, freeze-drying, and thermal imidization. The one-way growth of ice crystals endowed the composite aerogels with highly arranged tubular pores. The PI/graphene composite aerogels possessed anisotropic conductivity, electromagnetic interference (EMI) shielding, heat transfer, and compression performance. Moreover, the composite aerogels with low density (0.076 g·cm–3) exhibited high EMI shielding effectiveness (SE) of 26.1–28.8 dB, and its specific EMI SE value achieved 1373–1518 dB·cm2·g–1 when the graphene content was 13 wt %. The main electromagnetic interference shielding mechanism of these composite aerogels was microwave absorption. The composite aerogels had excellent thermal stability, and their 5% weight loss temperature was higher than 546 °C in nitrogen. This research provided an easy and environmentally friendly approach to prepare lightweight and anisotropic PI-based composite aerogels.
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