Polypyrrole/Schiff Base Composite as Electromagnetic Absorbing Material with High and Tunable Absorption Performance

Abstract

In recent years, Schiff base-related conjugated systems have received extensive attention, but little research has been done in the field of electromagnetic materials. In this work, an organic conjugated system based on polypyrrole/hydrazone Schiff base (PPy/HSB) composites was constructed via a Schiff base synthetic route and their electromagnetic behavior was investigated. The electromagnetic response of PPy/HSB complexes demonstrates fine electromagnetic absorption performance. When the filler loading is 30 wt% in a paraffin matrix, an absorption peak of −43.1 dB was achieved and its effective absorption bandwidth (EAB) was located in the range of 10.88−18.0 GHz. The electromagnetic response behavior of PPy/HSB complexes is explained by models involving electronic structure, multi-polarization and conductive network. The mechanisms of PPy/HSB complexes formation and HSB crystallization are also discussed through the compatibility of PPy/HSB and the structure of HSB. Moreover, the morphology transformation of HSB in the PPy/HSB systems has been studied. This study opens the exploration of organic–dielectric conjugated systems in the field of electromagnetic materials, and significantly broadens the application range of organic–dielectric–dielectric composites.

Co-Doped Porous Carbon/Carbon Nanotube Heterostructures Derived from ZIF-L@ZIF-67 for Efficient Microwave Absorption

“…As we know, the complex permittivity ( ε r = ε ′ − j ε ″) and permeability ( μ r = μ ′ − j μ ″) are crucial for the MA materials. In general, the real part values of both are mainly associated with the electrical and magnetic energy storage capacity of the material, while the imaginary part value corresponds to the dissipation capacity of electrical and magnetic energy [ 53 , 54 ]. As displayed in Figure 5 a,b, the real and imaginary parts of the permittivity for all samples exhibit a decreasing trend with increasing frequency, showing typical dispersive behaviour, which is often attributed to dipole orientation polarization [ 55 , 56 ].…”

Fabrication of the Fe-Doped Corona Schiff Base for Enhanced Microwave Absorption Performance

“…The stretching vibration of the characteristic peak C=N of the Schiff base reaches 1624 cm –1 . 28 , 29 The absorption peaks of symmetric and antisymmetric stretching vibrations of the primary amine N–H bond are located near 3421 cm –1 . The absorption peaks at 1401 and 1124 cm –1 are the characteristic absorption peaks of the skeletal bending motion of the C=C bond of the benzene ring and the stretching motion of the aromatic C–N bond, respectively.…”

“…20,21 Most researchers improve its wave-absorbing effect by compounding it with carbon materials, and the effect is significant. 22,23 It is worth noting that the excellent absorbing performance of this composite material is mainly provided by the strong dielectric loss capability of the carbon-based material itself, and the loss capability of the Schiff base absorber is not strong. For example, the Ag−Schiff base/rGO composite studied by Xu et al can reach an effective absorption bandwidth of 6.28 GHz.…”