Multifunctional Polymer Nanocomposites Toward Electromagnetic Interference Shielding

Multifunctional polymer nanocomposites including polyurethane nanocomposites reinforced with iron-silica core-shell nanoparticles, polypropylene nanocomposites reinforced with magnetic (magnetite, iron) nanoparticles and carbon nanotubes are fabricated  for electromagnetic interference shielding applications.  Parameters including filler surface treatment (controlled shell coating thickness), filler composition, and the effect of surfactant were systematically studied. Filler dispersion quality, morphology and the magnetic properties (coercivity, saturation magnetization) were studied. In addition, relative complex permittivity and relative complex permeability are investigated and the corresponding microwave absorption performances were calculated within the tested frequency ranging from 2 - 18 GHz. Results indicate that the polypropylene nanocomposites reinforced with the combination of iron nanoparticles and carbon nanotubes exhibited a reflection loss in a wider frequency ranges with the maximum reflection loss ranged from -22 to around -44 dB under different thickness. The results indicated that the relatively match permeability and permittivity was responsible for the high efficiency in the microwave absorptions. Also, the eddy current loss for the as-prepared nanocomposites was also studied and its influence on the microwave absorption performance was discussed in detail.