Thin and efficient EMI shielding materials from binary thermoplastic blend nanocomposites

EMI shielding materials and related research are of very relevance in this era of electronic gadgets. Here this report presents a binary thermoplastic blend nanocomposite system comprising poly-(trimethylene terephthalate) and polyethene compatibilized with multiwalled carbon nanotubes, which are showing superior electromagnetic interference (EMI) shielding compared to similar systems. The blend composition with a 90/10 ratio of PTT/PE was showing the optimum properties when a MWCNT concentration of 1 wt% was incorporated. The compatibilization efficacy was analyzed and confirmed through scanning and tunneling electron microscopes. The MWCNTs are preferably localized in the PTT phase. The blend system provides an electrical percolation threshold of 0.19 wt% due to the double percolating effect of the blend system and MWCNT in the PTT phase. It was observed that the EMI shielding value shows a corresponding increase with MWCNT loadings. The most favorable value obtained for EMI shielding effectiveness was ~32 dB and it was with 3 wt% MWCNT of film thickness 2 mm in range of frequency 2–4 GHz. The PTT/PE/MWCNT system was not considered for EMI applications anywhere else. The theoretical support of the experimental data was examined for DC conductivity employing different models such as Voet, Bueche, and Scarisbrick and the actual contribution of reflection, absorption, transmission loss to the total EMI shielding was done with Power balance. The present work is a facile and cost-effective method to fabricate lightweight and materials with high EMI shielding properties for mobile phones.