Electromagnetic wave absorption properties of rare earth element doped multi-walled carbon nanotubes/polyvinyl chloride composites

Multiwalled carbon nanotubes (MWCNTs) doped respectively La(NO₃)₃ and Ce(NO₃)₃ as absorber and polyvinyl chloride (PVC) as matrix were used to fabricate MWCNT/PVC composites. The microstructure and micromorphology of MWCNTs doped respectively La(NO₃)₃ and Ce(NO₃)₃ were investigated using transmission electron microscope (TEM) and X-ray diffraction (XRD). The electromagnetic wave absorption properties and pyrolysis behaviour of MWCNT/PVC, MWCNT-La(NO₃)₃/PVC and MWCNT-Ce(NO₃)₃/PVC composites were measured by a network analyzer and simultaneous thermal analysis. The results indicated that the electromagnetic wave absorbing properties of MWCNT/PVC composites were substantially improved after doping with a suitable amount of rare earth element in the frequency range from 2 to 18GHz, and the pyrolysis behaviour amost did not changed. In the range of R<-10dB of the reflection losses, the absorbing bandwidths of MWCNT-Ce(NO₃)₃/PVC composites was narrower (about 5.4 GHz) than that of MWCNT-La(NO₃)₃/PVC composites (about 5.6 GHz), and the absorption band and peak value shifted to the higher frequency region. It is favorable to improve the electromagnetic wave absorption properties of MWCNT/PVC composites in a high frequency region.