No abstract

No abstract

High‐frequency electromagnetic waves and electronic products can bring great convenience to people's life, but lead to a series of electromagnetic interference (EMI) problems, such as great potential dangers to the normal operation of electronic components and human safety. Therefore, the research of EMI shielding materials has attracted extensive attention by the scholars. Among them, polymer‐based EMI shielding materials with light weight, high specific strength, and stable properties have become the current mainstream. The construction of 3D conductive networks has proved to be an effective method for the preparation of polymer‐based EMI shielding materials with excellent shielding effectiveness (SE). In this paper, the shielding mechanism of polymer‐based EMI shielding materials with 3D conductive networks is briefly introduced, with emphasis on the preparation methods and latest research progress of polymer‐based EMI shielding materials with different 3D conductive networks. The key scientific and technical problems to be solved in the field of polymer‐based EMI shielding materials are also put forward. Finally, the development trend and application prospects of polymer‐based EMI shielding materials are prospected.

No 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 thermal 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 filler 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 310.7°C, increased by 62% and 6.9°C, 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.