Microwave dielectric properties and EMI shielding effectiveness of poly(styrene-b-styrene- butadiene-styrene) copolymer filled with PAni.Dodecylbenzenesulfonic acid and carbon black

Conducting composites of polyaniline doped with dodecylbenzenesulfonic acid (PAni.DBSA), carbon black (CB) and poly(styrene-b-styrene-butadiene-b-styrene) (STF) as supporting matrix were prepared by in situ polymerization. The influence of components and composition (% w/w) on the electromagnetic properties (dielectric constant epsilon' and the dielectric loss epsilon) and electromagnetic interference shielding effectiveness (EMI-SE) of the materials were evaluated with a waveguide, using a microwave network analyzer from 8.2 to 12.4 GHz (X-band). It was found that CB presence generates adverse effects on PAni.DBSA yield during synthesis, as it can be seen by X-ray diffraction and TGA analyses. The type of PAni.DBSA formed modifies the composites properties. Dielectric constant, loss factor, and EMI shielding increase with conductive filler loading. Both the fillers, individually and in combination, increase the properties; however, the effect is not additive in nature. POLYM. ENG. SCI., 52:20412048, 2012. (c) 2012 Society of Plastics Engineers