POLYPYRROLE-POLYPROPYLENE COMPOSITE FILMS - PREPARATION AND PROPERTIES

Polypyrrole-polypropylene conducting polymer composite films with good mechanical properties and high electrical conductivity were prepared using a two-direction permeation/diffusion polymerization method. The oxidant used was iron(III) chloride. Polypropylene microporous films p repared by the biaxial stretching technique were used as the matrix ma terial. The maximum conductivity of these composite films, 6.0 S cm(-1 ), is of the same order of magnitude as that of pure polypyrrole, 4.5 S cm(-1), which was synthesized by chemical oxidation of pyrrole monom er in aqueous solution. The composite films exhibit quite uniform mech anical properties in the film plane. Youngs modulus is in the range 0. 4-0.8 GPa, tensile strength 40-85 MPa and elongation at break 90-200%, maintaining the mechanical properties of polypropylene in the composi te. Polymerization conditions, including reaction time, reaction tempe rature and concentrations of the pyrrole and FeCl3 solutions, have a g reat influence on the structure and properties of the composite films. The structure of the conducting polymer in the composite films was ch aracterized by X-ray photoelectron spectroscopy and the surface morpho logy of the films was investigated using scanning electron microscopy. Two kinds of surface structure were observed, one is a loose particle structure and the other is a compacted surface structure.