Preparation and Properties of Electrically Conductive Polyaniline-Polystyrene Composites by in-situ Polymerization and Blending

Abstract

ABSTRACT:Electrically conductive polyaniline (PANI)-polystyrene (PS) composites were prepared by in-situ polymerization and blending. The polymerization was carried out by adding the oxidant and dodecylbenzenesulfonic acid (DBSA) dissolved in xylene to the xylene solution comprising aniline and PS. The electrical conductivity of PANI-PS composites was improved with increasing amount of PANI and reached a high value of 0.1 Scm-1 at content of 12wt%. The PANI content in PANI-PS composites was calculated by means of elemental analysis and weight measurements. The PANI-PS composites were very soluble in organic solvents such as chloroform, xylene, and N-methylpyrrolidone (NMP). The electrical conductivity of PANI, doped with dodecylbenzenesulfonic acid (DBSA), and thermally treated at 180°C for 3 h was more stable than that of conventional PANI-HCI complex. The structure and morphology of PA NI-PS composites were investigated through the measurements of FT-IR and SEM (scanning electron micrograph).KEY WORDS Polyaniline-Polystyrene Composite / Electrical Conductivity / Solubility / Thermal Stability / Structure / Conducting polymers have attracted considerable attention because of their electrical and optical properties and many potential applications such as energy storage, 1 electromagnetic interference shielding, 2 · 3 optoelectronic device, 4 • 5 and sensor, 6 etc. So far, however, only a few technical applications for this class of compounds have been realized, since organic conductive materials are, in general, very difficult to be processed. Several attempts have been made to improve the processibility of conducting polymers through the use of molecular design, 7 • 8 copolymerization, 9 and functionalized organic dopants.10·11 It has been recently reported that polyaniline (PANI) doped with organic protonic acids such as dodecylbenzenesulfonic acid (DBSA) and camphorsulfonic acid (CSA) could be soluble in chloroform, xylene, and m-cresol solvents. Thus, PANI composites could be obtained from solution blending in the conducting form. However, this method needs the complicated steps such as chemical polymerization of PANI in HCI solution, reduction of PANI-HCI complex in NaOH solution, redoping of PANI base with organic protonic acids, and solution blending of PANI and matrix polymer in organic solvents. 11 On the other hand, Ruckenstein et al. reported a route to prepare a PANI-polystyrene (PS) composite by emulsion pathway.12 This PANI was doped with HCI so that it significantly deteriorated at the elevated temperature of more than l 50°C under nitrogen, which is reported to be mainly due to the elimination of dopant molecule.In this study, we have developed a simple one-step process to prepare the conductive and thermally stablending. In order to improve the thermal stability of composites, DBSA and DDQ were used as a dopant and an oxidant, respectively. PS was used as a matrix polymer since it is one of the most general purpose polymer. The physical properties, structure, and thermal stability of t To whom c...

Synthesis and characterization of ferromagnetic polyaniline with conductivity in an applied magnetic field

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