Enhanced electromagnetic wave absorption of engineered epoxy nanocomposites with the assistance of polyaniline fillers

Abstract

In this work, the engineered polyaniline (PANI)/epoxy composites reinforced with PANI-M (physical mixture of PANI spheres and fibers) exhibit significantly enhanced electromagnetic wave absorption performance and mechanical property. Due to the synergistic effect of PANI fillers with different geometries, the reflection loss of 10.0 wt% PANI-M/epoxy could reach − 36.8 dB at 17.7 GHz. Meanwhile, the mechanical properties (including tensile strength, toughness, and flexural strength) of PANI/epoxy were systematically studied. Compared with pure epoxy, the tensile strength of epoxy with 2.0 wt% PANI-M was improved to 86.2 MPa. Moreover, the PANI spheres (PANI-S) and PANI fibers (PANI-F) were prepared by the chemical oxidation polymerization method and interface polymerization method, respectively. The characterizations including scanning electron microscope, Fourier transform infrared spectra, and X-ray diffraction were applied to analyze the morphology and chemical and crystal structures of PANI filler. This work could provide the guideline for the preparation of advanced engineered epoxy nanocomposites for electromagnetic wave pollution treatment. Graphical abstract

Electrostatic Adsorption Enables Layer Stacking Thickness‐Dependent Hollow Ti3C2Tx MXene Bowls for Superior Electromagnetic Wave Absorption

“…The much higher ε′ and ε″ values of the pristine MXene nanosheets compared to those of the MXene bowls indicated that the bowl‐like structures endowed the MXenes with moderate permittivity, facilitating a well‐matched impedance (Figures S18 and S19, Supporting Information). [ 59 ]…”

“…The much higher ε′ and ε″ values of the pristine MXene nanosheets compared to those of the MXene bowls indicated that the bowl-like structures endowed the MXenes with moderate permittivity, facilitating a well-matched impedance (Figures S18 and S19, Supporting Information). [59] The dielectric loss tangent (tan δ ε ), defined as ε″/ε′, represents the ability to convert EM energy into heat energy by the attenuation of time-varying EM field-induced currents in conducting networks. [60] The tan δ ε -f curve of M-2 and M-4 showed significant resonance peaks, indicating the existence of polarization relaxations (Figure S20a, Supporting Information).…”

Greatly Enhanced Electromagnetic Interference Shielding Effectiveness and Mechanical Properties of Polyaniline-Grafted Ti3C2Tx MXene–PVDF Composites

“…This might be related to the quality of the dispersion of the nanoflakes in the PVDF matrix. Generally, the achievement of high-quality dispersion of the nanofiller in a polymer matrix is a challenging issue, especially at higher loadings. , Although the processing conditions are an important parameter that could impact on the dispersion quality of the nanoflakes in composites, at the same ensured processing conditions, compatibility between the polymer and the nanofiller plays a decisive role in reducing the risk of nanofiller aggregation and thus enhancing the dispersion quality. Better nanofiller dispersion could not only reduce the stress concentration sites in the composite but also improve the polymer–filler interactions and enhance the capability of the composite to withstand higher stress before failure.…”

A Multifunctional Flexible Electronic Skin for Dynamic Thermal Radiation Regulation and Electromagnetic Interference Shielding

“…For PANI/MXene/nylon films, the EMI SE performance and power coefficient with opposite incident direction of EM wave are depicted in Figure S14 and Figure S15. When the EM waves are first incident on PANI layer, the A value is decreasing and always less than the R value, indicating that when the EM waves arrive at the surface of object, the reflection is inferior to the absorption due to the impedance mismatch. , When the EM waves are first incident on MXene layer, the EMI SE performance is similar to that on PANI layer; however, the larger R value indicates a better reflection ability of MXene layer. Also, it means a reliable reflection-dominated shielding mechanism no matter from which side the EM waves are incident.…”

“…50,51 When the EM waves are first incident on MXene layer, the EMI SE performance is similar to that on PANI layer; however, the larger R value indicates a better reflection ability of MXene layer. Also, it means a reliable reflection-dominated shielding mechanism no matter from which side the EM waves are incident.…”