Preparation of polyaniline/polyacrylate composites and their application for electromagnetic interference shielding

Abstract

Polyaniline (PANI) deposited polyacrylate (PA) powders were prepared by chemical polymerization of aniline in hydrochloric acid with dispersed PA powders. The powders, after dedoped with ammonia water, were re-doped with camphorsulfonic acid (CSA) to render them conductive, and conductive PANI/polyacrylate composite coatings (PANI/PA) were prepared by bead milling of these CSA-doped PANI (PANI–CSA) deposited polyacrylate powders (PANI–CSA/PA). It was found that aniline was polymerized preferentially at the surfaces of the powders and PANI deposited powders were obtained as indicated by the scanning electronic microscopy images. The amount of deposited PANI increased with the aniline/polyacrylate weight ratio in feed, and no isolated PANI particles was found. UV–Vis and Fourier transformed infrared spectra indicated that the PANI layer was physically adhered to the PA powders, and not chemically. Conductivities of the PANI–CSA/PA powders and the PANI/PA coatings increased with the amounts of PANI–CSA and a percolation threshold of 0.2 and 0.3 was demonstrated, respectively. Electromagnetic interference shielding measurements showed that the shielding effectiveness of the PANI/PA coatings increased with PANI–CSA loadings, and shielding effectiveness as high as 60 dB can be achieved with the coatings. POLYM. COMPOS., 27:627–632, 2006. © 2006 Society of Plastics Engineers