Thermal dynamic processing of polyaniline with dodecylbenzene sulfonic acid

To attain an intrinsically conductive and processible polymer, polyaniline (PANI)/dodecylbenzene sulfonic acid (DBSA) blends of several compositions were processed at various elevated temperatures in a Brabender plastograph. The blends' temperatures during processing, as affected by the blends' composition and initial process temperature, were monitored. Accordingly, the process includes the following main stages: heating the blend, exothermic PANI-DBSA doping reaction accompanied by a paste to a solidlike transition, and plasticization of the resulting PANI/DBSA complex by the excess DBSA. Composition analysis of the process products sampled at the various stages showed that the initial blends, prior to their thermal processing, already consisted of partially doped PANI particles, having a core/shell structure; the core consists of PANI(base) and the shell of PANI(DBSA)(0.32) complex. In addition, at the paste-to-solid-like transition, the doping reaction is completed; further mixing does not affect the complex composition, but results in conductivity reduction. The morphology of the blends sampled at the various processing stages was studied by electron microscopy. From the conductivity and processibility point of view, optimal PANI/DBSA blend composition and processing temperature were identified. (C) 1997 John Wiley & Sons, Inc.