Efficient electromagnetic wave absorption of polypyrrole/low-reduction graphene oxide composites through dielectric properties modulation

Abstract

Graphene oxide (GO) is widely used in electromagnetic microwave absorption (EMA) materials due to its abundant oxygen-containing functional groups and defects. Its conductivity, surface functional groups and defect density can be modified by controlling reduction degree to modulate its electromagnetic properties. However, the thermal reduction temperature needed is often too high, exceeding the Curie temperature of magnetic materials, which makes further compounding difficult. Polypyrrole (PPy), as a conductive polymer with high electrical conductivity, is widely used in EMA field and can help regulate the dielectric properties of materials. In this paper, a series of PPy/GO composites with different ratios and reduction degrees were prepared by in situ polymerization and thermal reduction, and their EMA properties were investigated. At a loading amount of 7.5 wt%, the maximum reflection loss of PPy/rGO composites can reach −66.64 dB, and the effective absorption bandwidth can reach 6.74 GHz with a reduction temperature of only 400 °C. Furthermore, the unreduced sample also has excellent absorption performance, which has a wide range of applications for future one-step compositing with magnetic materials in low reduction temperature.