BITS Faculty Publications

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    The influence of Fe3O4@GNP hybrids on enhancing the EMI shielding effectiveness of epoxy composites in the X-band
    (Elsevier, 2020-07) Etika, Krishna Chitanya
    In this work, the electromagnetic interference (EMI) shielding effectiveness in the X band frequency range of 8–12.4 GHz of epoxy nanocomposites containing Fe3O4 nanoparticles decorated graphene nanoplatelets (i.e., Fe3O4@GNP hybrids) is investigated. The hybrid nanostructures were synthesized in situ by a simple co-precipitation technique and were incorporated into the epoxy matrix by melt blending following a solvent-less approach. Scanning electron microscopy performed on the hybrid nanostructures revealed a good distribution of Fe3O4 nanoparticles on the GNP sheets in the hybrid. A series of epoxy nanocomposites containing varying content of Fe3O4@GNP, GNP and/or Fe3O4 nanoparticles were synthesized and compared for their EMI shielding effectiveness. The SEM of the composite cross-section reveals good filler dispersion in the composites. Overall the nanocomposites containing Fe3O4@GNP hybrids exhibited enhanced EMI shielding performance when compared to samples containing equivalent loading of only GNP and/or Fe3O4. The 1 mm thick composite sample containing 1:3 (wt/wt) Fe3O4: GNP hybrid attenuated 89 % of incident wave power and exhibited an EMI shielding effectiveness value of 9.6 dB in the X-band.
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    Environmentally friendly low-cost graphene oxide-cellulose nanocomposite
    (Elsevier, 2022-07) Etika, Krishna Chitanya
    This study primarily aims to develop a simple, cost-effective, eco-friendly nanocomposite filter for dye removal by adsorption. In this work, graphite oxide and graphene oxide were synthesized using a modified Hummers’ process and used to fabricate nanocomposite filters by co-precipitation reactions. Scanning electron microscopy and X-ray diffraction were performed on nanofillers revealing crystallographic and morphological properties of the nanofillers.
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    Enhanced thermo-mechanical, thermal and EMI shielding properties of MWNT/MAgPP/PP nanocomposites prepared by extrusion
    (Elsiever, 2021-03) Etika, Krishna Chitanya
    In this work, multiwalled nanotube/maleic anhydride–grafted polypropylene/polypropylene (MWNT/MAgPP/PP) nanocomposites are produced using an industrially relevant twin-screw extrusion process. The composites with varying nanotube content in the range of 0.5 wt% to 2 wt% were synthesized and evaluated for their thermo-mechanical (i.e., Vicat softening temperature (VST), heat deflection temperature (HDT)), thermal (i.e., Melting (Tm) temperature, crystallization (Tc) temperature and thermal decomposition (Td) temperature), and electromagnetic interference (EMI) shielding properties. The scanning electron microscopy (SEM) of composite cross-sections reveal uniform dispersion of MWNTs in the polymer matrix. Overall, the MWNT content in the composites was found to influence the composite properties with higher nanotube loadings resulting in a higher increase in the measured properties over the MAgPP/PP sample. The composite containing 2wt% MWNTs exhibited the highest increase of 33.42%, 15.52%, 15.42%, 10.23%, over the pure MAgPP/PP sample in its Tdi, Tdf, VST and HDT values, respectively. The electromagnetic interference (EMI) shielding effectiveness of 2 mm thick sample containing 2wt% MWNTs content was measured to be 5.9 dB in the X-Band frequency range of 8–12.4 GHz, which corresponds to 74.29% attenuation of incident wave power. The results obtained suggest the viability of the masterbatch based extrusion method as a potential strategy for the large-scale production of nanocomposites.