[Research]3D Shapeable, Superior Electrically Conductive Cellulose Nanofibers/Ti3C2Tx MXene Aerogels/Epoxy Nanocomposites for Promising EMI Shielding
作者：Lei Wang, Ping Song, Cheng-Te Lin, Jie Kong and Junwei Gu*
關鍵字：Electrically Conductive ,Cellulose Nanofibers, MXene Aerogels
論文來源：期刊
具體來源：Research
發表時間：2020年
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.
本工作基于定向冷凍-冷凍干燥法制備3D各向異性高導電纖維素納米纖維/Ti3C2Tx氣凝膠（CTA），再經熱還原-真空輔助浸漬法制備熱還原Ti3C2Tx氣凝膠（TCTA）/環氧樹脂納米復合材料。結果表明，TCTA/環氧樹脂納米復合材料具有完整、高效的3D導電網絡和極低的滲濾閾值（0.20 vol% Ti3C2Tx）。當TCTA體積分數為1.38 vol%時，TCTA/環氧樹脂納米復合材料的徑向電導率（σ）、軸向EMI SE和單位厚度屏蔽效能（SE/d）分別高達1672 S m-1、74 dB和37 dB mm-1，均幾乎優于以往報道的聚合物基導電復合材料。此時，TCTA/環氧樹脂納米復合材料還具有優異的力學性能和熱穩定性，其儲能模量和耐熱指數（THRI）分別為9792.5 MPa和310.7oC，較熱還原纖維素納米纖維/環氧樹脂納米復合材料分別提高了62%和6.9oC。這種輕質、簡單易得、可塑性強的高導電、高屏蔽效能、優異力學性能和出眾熱穩定性的TCTA/環氧樹脂納米復合材料的制備及批量化生產將大大拓寬MXene納米材料在EMI領域中更廣的應用。