Poly(3-methylthiophene)-Rubber Conductive Composite Prepared via an Inverted Emulsion Pathway *

An inverted emulsion pathway was employed to prepare poly(3-methylthiophene)-rubber conductive composites. In the first step, an inverted emulsion containing an aqueous solution of FeCl₃ as dispersed phase and an organic solution of a host polymer and a surfactant as continuous phase were generated. In the second step, a toluene solution of 3-methylthiophene was introduced dropwise into the inverted emulsion where the monomer was polymerized by the oxidant FeCl₃ to the conductive polymer. After the completion of polymerization, the composite was obtained by precipitating the conductive polymer and the host polymer. Under suitable preparation conditions, composites with both high conductivities and good mechanical properties were obtained; these composites had a conductivity as high as 1.3 S/cm as well as a tensile strength of 14.8 MPa and an elongation of 84.0% at break point. Among thiophene, 2,2′-bithiophene and 3-methylthiophene, the latter monomer is the most suitable for preparing thiophene-containing conductive composites by the inverted emulsion method.