Microwave Absorption Properties of Doped Polypyrrole with Sodium Dodecyl Benzene Sulfonate

Polypyrrole(PPy) with varied dopant concentration is synthesized by emulsion polymerization with the SDBS as the dopant.The n(S)/n(N) measured by element analysis is used to donate the doped degree.The conductivity of PPy doped with varied SDBS concentration is measured and it is found that with the SDBS concentration increasing,the conductivity firstly increases then decreases.The doped PPy is used as the microwave absorber to prepare microwave absorption materials-epoxy resin composites.The electromagnetic properties of the epoxy resin composites are tested and the reflection loss is calculated according to the single-layer microwave absorber model.The results show that the microwave absorption properties of the epoxy resin composites with the PPy doped with n(SDBS)/n(Py)=0.2 as the absorber and 20wt% content in the composites are the best.The minimum reflection loss is-14.8dB at 2.3mm thickness and the reflection loss is under-10dB in the frequency range of 9.5~11.6GHz.