Polyaniline Wrapped Graphene/TPU Composites – A Potential Candidate for Electromagnetic Interference Shielding

Abstract

Graphene-based polymer nanocomposites have been considered to have a significant promise to create commercially viable electromagnetic interference (EMI) shielding materials. In the present study, we carry out a systematic analysis of the EMI shielding ability of Polyaniline wrapped graphene nano sheets in thermoplastic polyurethane (TPU) matrix. The composites were prepared by solution casting method using graphene coated with polyaniline. The coating was done by in-situ and ex-situ chemical oxidation polymerization of aniline in presence of graphene nano sheets (GN). The composites thus prepared were designated as GN/PANI/TPU(I) and GN/PANI/TPU(E), respectively. In-situ polymerisation was carried out to achieve excellent dispersion and adhesion of the conductive filler in the TPU matrix. The improved dispersion of conductive filler in the case of PANI/GN/TPU(I) composites was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The electrical and electromagnetic interference (EMI) shielding properties of the prepared composites were studied. The percolation threshold of GN/PANI/TPU(I) composites was found low (0.46 wt %). These composites displayed a conductivity of 31.56 S/m and EMI shielding efficiency of 40.6 dB in X band region at 6% filler concentration. For GN/PANI/TPU (E) composites, the corresponding values were 5.18 S/m and 23.4 dB respectively. This improved efficiency of EMI shielding can be caused by a well-organized conductive network of fillers in TPU matrix.