Influence of coordination complexes of transition metals on EMI-shielding properties and permeability of polymer blend/carbon nanotube/nickel composites

In this work the influence of transition metal coordination compounds was analyzed on the EMI-shielding characteristics and permeability for a paramagnetic probe of polymer composites based on cross-linked polyurethane or incompatible polymer blend (simultaneous semi-IPN based on cross-linked polyurethane and linear poly(methylmethacrylate) filled in situ with conductive and/or magnetic filler. Cross-linked polyurethane/carbon nanotube composites, polymer blend/carbon nanotube composites and polymer blend/carbon nanotube/nickel composites contained of 1.5 wt% and 3 wt% of fillers were modified with Fe(3+)acetylacetonate or Cr(3+) acetylacetonate coordination compounds of different complexing ability. It was shown that opposite effect of Fe(3+) and Cr(3+) complexes on the phase separation in the polymer blend allows regulate the level of the multiple reflection of the electromagnetic wave at the interfacial boundaries as well as protective characteristics and permeability of the investigated systems. The shielding efficiency of chromium-modified composite in the frequency range of (25.8-37.5) GHz is up to 25 dB in the segregated polymer. It has been shown that the effect of conductive nanofillers on polymer loosening is opposite to that of magnetic fillers and is sensitive to the presence in the system of coordination complexing agent.