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A copolymer of pyrrole and o-aminophenol was synthesized by single step oxidative polymerization technique. Two different nanocomposites of copolymer with α-Fe 2 O 3 and Co-α-Fe 2 O 3 were prepared and acetone sensing property of both composites were studied at room temperature with different gas concentrations. The calculated sensitivity of the Co-α-Fe 2 O 3 nanocomposite was 0.68 and α-Fe 2 O 3 nanocomposite was 0.44. The sensitivity of prepared composites was higher than the pure polymer.The LOD of the α-Fe 2 O 3 composite was found to be 0.13 ppm and Co-α-Fe 2 O 3 composite was 0.37 ppm. Both the prepared composites have showed excellent selectivity with good repeatability for the acetone gas. The 20% Co-Fe 2 O 3 containing nanocomposite sensor exhibited faster response time of 1.4 s and recovery time of 4.4 s towards the target gas and 15% α-Fe 2 O 3 containing nanocomposite sensor exhibited the response time of 1.4 s and recovery time of 4.8 s for the acetone gas.The polymer and the nanocomposites have shown excellent repeatability for 7 cycles.The faster response of the sensor can be attributed to the increased number of oxygen vacancies on the sensor as well as the free O H groups present in the polymer back bone.

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The present work aimed at the simultaneous improvement in the mechanical and electromagnetic shielding properties of Fe3O4‐carbonaceous/epoxy composites by the reinforcement of two plies of carbon fiber into the epoxy‐filler matrix. In this study, Fe3O4‐activated carbon and Fe3O4‐activated charcoal composites were synthesized by co‐precipitation method and were introduced into the epoxy matrix with different weight percentage (5, 10, and 15 wt%). The BET surface area analysis revealed the high porosity in the Fe3O4‐activated charcoal composite than that of activated carbon composite. The Fe3O4‐activated carbon/epoxy composite showed better mechanical properties than the later. Both the composites showed nearly same EMI SE value. 10 wt% of the filler‐1/epoxy composite showed the highest shielding effectiveness (SE) value of −22.5 dB at 10 GHz whereas 15 wt% Fe3O4@charcoal/epoxy composite showed better SE value of −27.15 dB at 8.8 GHz. The obtained results were supported by the dielectric and magnetic loss tangent studies. The incorporation of carbon fiber enhanced the mechanical property by three times and the EMI SE value by ~15 dB. Thus, the carbon fiber reinforced Fe3O4/carbonaceous epoxy composites may be the potential electromagnetic shielding material for electronics and aircraft industries.

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