Effect of crosslinking reaction on the electromagnetic interference shielding of a Fe-Si-Al alloy (Sendust)/polymer composite at high frequency

In recent years, development of advanced electronic devices and communication instruments has led to increased demand for electromagnetic interference (EMI) shielding because high-frequency microwave generates undesired noise which can affect the proper operation of commercial, military and scientific electronic devices as well as the health of our human body. In this study, we investigated the effect of crosslinking reaction of polymer matrix on the EMI shielding performance of a Fe-Si-Al alloy (Sendust)/polymer (poly(styrene-b-ethylenebutadiene-b-styrene)) composite. The crosslinking reaction of polymer matrix enhanced the melt viscosity of the polymer blend which helped the alignment of the metal flake into rolling direction to induce enhanced anisotropy of the composite. The complex permeability of the flake composite was substantially increased, and the reflection loss at 0.8GHz was -9.3dB. The absorption efficiency of the crosslinked polymer/flake composite was dramatically increased around 1GHz compared to the crosslinked/bulk powder composite. Normalized power loss reached almost 1 in Giga Hertz frequency. The Sendust/polymer composites are practically useful for the EMI shielding purpose.