Effect of Temperature and Frequency on Microwave Shielding Behaviour of Functionalized Kenaf Fibre-Reinforced MWCNTs/Iron(III) Oxide Modified Epoxy Hybrid Composite

A strong conductive and magnetically strengthened microwave shielding hybrid epoxy composite was prepared and analyzed. The principal aim of this research work was to prepare a high stable microwave shielding hybrid epoxy composite with surface modified MWCNTs and iron(III) oxide nano particles. The surface-modification on these reinforcements favour the composites been retained their magnetic and electrical conductivity even in elevated temperatures 100 degrees C and 200 degrees C and frequency up to 50 GHz. The kenaf fibre, MWCNTs and iron(III) oxide particles were surface-modified by APTMS for effective protection of reinforcements. The composites were prepared using hand layup method. The additions of silane-treated kenaf fibre and MWCNTs with iron(III) oxide into epoxy resin improved the mechanical properties, the same has been discussed in the previous article by the author. The silane surface-modified composites gave unaltered dielectric constant and microwave shielding behaviour in elevated temperatures. The acquisition of residual magnetism remains same as room temperature and 200 degrees C. The maximum relative magnetic permeability of 1.2 and dielectric constant of 4.0 was observed for composite designation 'E' in room temperature. Similarly maximum EM wave attenuation of 44 dB was achieved in J band frequency at 200 degrees C. These high stable microwave shielding composite materials are capable of serving as shielding materials in electronic communication gadgets, radar and microwave shielding helmets.