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Updated: Jan 29, 2026

Application of a Coupling Agent to Improve the Dielectric Properties of Polymer-Based Nanocomposites
Published on: September 19, 2020
Enhanced microwave absorption properties of PMMA modified MnFe2O4-polyaniline nanocomposites
R V Lakshmi1, Parthasarathi Bera, R P S Chakradhar
1Surface Engineering Division, CSIR-National Aerospace Laboratories, Bengaluru 560017, India. lakshmi_rv@nal.res.in partho@nal.res.in.
Abstract:
A manganese based spinel ferrite, chemically modified with polymethyl methacrylate (PMMA) and polyaniline (PANI) are synthesized and their composites are used as electromagnetic interference (EMI) shielding materials. X-ray diffraction studies show that the as-prepared manganese ferrite crystallizes in a cubic spinel structure. The particles are highly agglomerated and nanocrystalline as indicated by transmission electron microscopy. Manganese exists in +2 and +4 oxidation states and Fe in +2 and +3 oxidation states. Modified manganese ferrite and polyaniline composites in different weight ratios are evaluated for their EMI shielding properties. It is observed that composites containing the PMMA modified ferrite show enhanced total shielding effectiveness (SET) compared to those containing the unmodified ferrite in the X band frequency range (8-12 GHz). The optimized ratio of the PMMA modified ferrite and PANI demonstrates SET values as high as ∼44 dB in the X band frequency range.
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