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Enzymatically degradable EMI shielding materials derived from PCL based nanocomposites

Pawar, Shital Patangrao and Kumar, Sachin and Misra, Anupam and Deshmukh, Subrajeet and Chatterjee, Kaushik and Bose, Suryasarathi (2015) Enzymatically degradable EMI shielding materials derived from PCL based nanocomposites. In: RSC ADVANCES, 5 (23). pp. 17716-17725.

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Official URL: http://dx.doi.org/ 10.1039/c4ra10364e

Abstract

In this study, two different types of multiwall carbon nanotubes (MWNTs) namely pristine (p-MWNTs) and amine functionalized (a-MWNTs) were melt-mixed with polycaprolactone (PCL) to develop biodegradable electromagnetic interference (EMI) shielding materials. The bulk electrical conductivity of the nanocomposites was assessed using broadband dielectric spectroscopy and the structural properties were evaluated using dynamic mechanical thermal analysis (DMTA). Both the electrical conductivity and the structural properties improved after the addition of MWNTs and were observed to be proportional to the increasing fractions in the nanocomposites. The shielding effectiveness of the nanocomposites was studied using a vector network analyzer (VNA) in a broad range of frequencies, X-band (8 to 12 GHz) and K-u-band (12 to 18 GHz) on toroidal samples. The shielding effectiveness significantly improved on addition of MWNTs, more in the case of p-MWNTs than in a-MWNTs. For instance, at a given fraction of MWNTs (3 wt%), PCL with p-MWNTs and a-MWNTs showed a shielding effectiveness of -32 dB and -29 dB, respectively. Moreover, it was observed that reflection was the primary mechanism of shielding at lower fractions of MWNTs, while absorption dominated at higher fractions in the composites. As one of the rationales of this work was to develop biodegradable EMI shielding materials to address the challenges concerning electronic waste, the effect of different MWNTs on the biodegradability of PCL composites was assessed through enzymatic degradation. The enzymatic degradation of the samples cut from the hot pressed films by bacterial lipase was investigated. It was noted that a-MWNTs exhibited almost similar degradation rate as the control PCL sample; however, p-MWNTs showed a slower degradation rate. This study demonstrates the potential use of PCL-MWNT composites as flexible, light weight and eco-friendly EMI shielding materials.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 01 Apr 2015 12:12
Last Modified: 01 Apr 2015 12:12
URI: http://eprints.iisc.ac.in/id/eprint/51153

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