Open Access Nano Express

Improved Electromagnetic Interference Shielding Properties of MWCNT–PMMA Composites Using Layered Structures

Shailaja Pande1, BP Singh1, RB Mathur1*, TL Dhami1, P Saini2 and SK Dhawan2

Author Affiliations

1 Carbon Technology Unit, Division of Engineering Materials, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012, India

2 Polymeric and Soft Materials Section, National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi, 110012, India

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Nanoscale Research Letters 2009, 4:327-334  doi:10.1007/s11671-008-9246-x

Published: 17 January 2009

Abstract

Electromagnetic interference (EMI) shielding effectiveness (SE) of multi-walled carbon nanotubes–polymethyl methacrylate (MWCNT–PMMA) composites prepared by two different techniques was measured. EMI SE up to 40 dB in the frequency range 8.2–12.4 GHz (X-band) was achieved by stacking seven layers of 0.3-mm thick MWCNT–PMMA composite films compared with 30 dB achieved by stacking two layers of 1.1-mm thick MWCNT–PMMA bulk composite. The characteristic EMI SE graphs of the composites and the mechanism of shielding have been discussed. SE in this frequency range is found to be dominated by absorption. The mechanical properties (tensile, flexural strength and modulus) of the composites were found to be comparable or better than the pure polymer. The studies therefore show that the composite can be used as structurally strong EMI shielding material.

Keywords:
Carbon nanotubes; Dispersion; Composites; Electrical conductivity; EMI shielding effectiveness