Part-A: Synthesis of polyaniline and carboxylic acid functionalized SWCNT composites for electromagnetic interference shielding coatings

Polyaniline (PANI) was synthesized by chemical oxidation process by using Ammonium persulphate (APS) as an oxidizer and HCl as a dopant. The effects of altering the stoichiometric ratio of monomer to oxidizer, addition time, reaction temperature and dopant concentration on the electrical conductivity of PANI were studied in detail. The synthesis procedure was optimized to yield the PANI with maximum electrical conductivity. The pure PANI thus synthesized exhibited the maximum electrical conductivity 5.6 Scm⁻¹. Different PANI–cSWCNT composites were prepared by ex-situ and in-situ methods and a comparative evaluation of electrical conductivity was carried out. From the electrical conductivity measurements, it was seen that maximum conductivity 27.12 Scm⁻¹ was achieved for 20% cSWCNT loaded PANI composite prepared by in-situ method and 12 Scm⁻¹ for the same composite prepared by ex-situ method. The efficacy of in-situ method, for conductivity enhancement was attributed to the formation of PANI coating over cSWCNT during the synthesis. This coating formation was further substantiated by FTIR, XRD, DSC, TGA, FESEM, and HRTEM analysis. The results of these studies confirmed that the in-situ prepared 20% cSWCNT loaded PANI composite is the most preferred filler for developing polyurethane based EMI shielding coatings.