Highly Electrically Conducting Polyurethane-Based Composite

The preparation of a new conducting composite based on a polyurethane (PU) membrane radiatively grafted with poly(acrylamide) (PAAm) is described. Polypyrrole (PPy) was inserted into the PU/PAAm composite using a new chemical-electrochemical catalytic method. The hydrophilicity of the host matrix is essential for the incorporation of the conducting phase throughout the film in aqueous solution, and also the interaction between the insulating host membrane and the PPy is important to achieve high conductivity. Conductivities as high as 100 S cm⁻¹ were obtained. The environmental stability of these films was good: 97% of the initial conductivity retains after 100 days. Flexible, stretchable, and strong conducting films can be prepared. Films that exhibit conductivity of 70 S cm⁻¹ could be stretched up to 24% of their original length. Thick transparent films having fairly high levels of conductivity were prepared in methanol-water solution. The mechanical and thermal properties and composition of the new conducting composite are reported.