Conducting SBS block copolymer-polyaniline blends prepared by mechanical mixing

Polyaniline was doped with dodecylbenzenesulfonic acid (Pani . DBSA) in an agate mortar and used as a conductive additive in melt blends with styrene-butadiene-styrene (SBS) block copolymer. These blends exhibit relatively high levels of electrical conductivity at low-weight fractions of the polyaniline complex. The melt blending process, performed in a two-roll mill or in a Haake internal mixer, increased the protonation degree of the Pani . DBSA, as indicated by X-ray photoelectron spectroscopy analysis. This result confirms the occurrence of a second doping process at high temperature. The mechanical performance decreases as the amount of Pani . DBSA in the blend increases, indicating a plasticizing effect of the DBSA. The higher temperature used in blending imparts better conductivity value but gives rise to a strong crosslinked material because of the presence of the sulfonic acid and the high extent of double bonds in the SBS compound. (C) 2001 John Wiley & Sons, Inc.