CONDUCTIVE POLYANILINE-SBS COMPOSITES FROM IN-SITU EMULSION POLYMERIZATION

The composites of polyaniline (PAn) and SBS were made by polymerizatio n of aniline in the presence of SBS, using a direct, one-step in situ emulsion polymerization technique. The polymerization of aniline was c arried out in an emulsion comprising water and xylene containing SBS i n the presence of dodecylbenzene sulfonic acid, acting both as a surfa ctant and a dopant for PAn. The composites obtained can be processed b y melt method (MP) or solution method (SP). Conductivity of the compos ites processed by different methods exhibits different percolation thr esholds: 10 wt% for MP sample and 7 wt% for SP sample. At the same con tent of PAn, the conductivity of SP composite is higher than that of M P composite. The relationships between mechanical properties and PAn c ontent, as well as morphological structure of the composites obtained by the two different processing methods were studied. When the PAn con tent is lower than 12 wt%, the composites behave like a thermoplastic elastomer with high elongation (similar to 600%) and low permanent set (<50%). The conductivity of composite after secondary doping with m-c resol is about two orders of magnitude higher than the original. (C) 1 998 Elsevier Science Ltd. AU rights reserved.