Lei Wang, Ping Song, Cheng-Te Lin, Jie Kong and Junwei Gu*. 3D Shapeable, Superior Electrically Conductive Cellulose Nanofibers/Ti3C2Tx MXene Aerogels/Epoxy Nanocomposites for Promising EMI Shielding. Research, 2020, 2020: 4093732.
https://doi.org/10.34133/2020/4093732
Abstract: In this work, 3D highly electrically conductive cellulose nanofibers (CNF)/Ti3C2Tx MXene aerogels (CTA) with aligned porous structures are fabricated by directional freezing followed by freeze-drying technique, and the thermally annealed CTA (TCTA)/epoxy nanocomposites are then fabricated by thermally annealing of CTA, subsequent vacuum-assisted impregnation and curing method. Results show that TCTA/epoxy nanocomposites possess 3D highly conductive networks with ultralow percolation threshold of 0.20 vol% Ti3C2Tx. When the volume fraction of Ti3C2Tx is 1.38 vol%, the electrical conductivity (σ), electromagnetic interference shielding effectiveness (EMI SE), and SE divided by thickness (SE/d) values of the TCTA/epoxy nanocomposites reach 1672 S m-1, 74 dB, and 37 dB mm-1, respectively, which are almost the highest values compared to those of polymer nanocomposites reported previously at the same fillers content. In addition, compared to those of the samples without Ti3C2Tx, the storage modulus and heat-resistance index of TCTA/epoxy nanocomposites are enhanced to 9792.5 MPa and 310.7oC, increased by 62% and 6.9oC, respectively, presenting outstanding mechanical properties and thermal stabilities. The fabricated lightweight, easy-to-process, and shapeable TCTA/epoxy nanocomposites with superior EMI SE values, excellent mechanical properties, and thermal stabilities greatly broaden the applications of MXene-based polymer composites in the field of EMI shielding.本工作基于定向冷冻-冷冻干燥法制备3D各向异性高导电纤维素纳米纤维/Ti3C2Tx气凝胶（CTA），再经热还原-真空辅助浸渍法制备热还原Ti3C2Tx气凝胶（TCTA）/环氧树脂纳米复合材料。结果表明，TCTA/环氧树脂纳米复合材料具有完整、高效的3D导电网络和极低的渗滤阈值（0.20 vol% Ti3C2Tx）。当TCTA体积分数为1.38 vol%时，TCTA/环氧树脂纳米复合材料的径向电导率（σ）、轴向EMI SE和单位厚度屏蔽效能（SE/d）分别高达1672 S m-1、74 dB和37 dB mm-1，均几乎优于以往报道的聚合物基导电复合材料。此时，TCTA/环氧树脂纳米复合材料还具有优异的力学性能和热稳定性，其储能模量和耐热指数（THRI）分别为9792.5 MPa和310.7oC，较热还原纤维素纳米纤维/环氧树脂纳米复合材料分别提高了62%和6.9oC。这种轻质、简单易得、可塑性强的高导电、高屏蔽效能、优异力学性能和出众热稳定性的TCTA/环氧树脂纳米复合材料的制备及批量化生产将大大拓宽MXene纳米材料在EMI领域中更广的应用。
附第一作者（王雷）个人简介：。
王雷，男，陕西商洛人，2018级博士研究生。2016年在西北工业大学获学士学位，2016年免试攻读硕士学位并于2018年硕博连读。主要从事3D MXene泡沫、气凝胶结构及其环氧树脂基电磁屏蔽复合材料的制备及机理研究。参与航天科学技术基金2项和校研究生种子基金2项。2018~2019学年博士研究生国家奖学金获得者。在Research、Carbon、Composites Part B: Engineering和Journal of Materials Science & Technology等期刊发表SCI论文16篇，其中第一作者（含导师第一）SCI论文6篇。SCI引用650余次（入选第一作者ESI热点论文2篇、高被引论文2篇），H因子11；参加国际会议3次并作口头报告；授权、公开国家发明专利8件。