New conducting thermoplastic elastomers.Part 1-Synthesis and characterization

In the last 20 years, much interest has been focused on conducting polymers to find new materials to transfer from research to industry. However, in many cases, as for elastomers for which intrinsically conducting materials are unavailable, it is necessary to use conducting particles that are physically mixed with the polymeric matrix to give loaded rubbers. In this work we report the synthesis and the chemical characterization of an intrinsically conducting material with good mechanical and electrical conduction properties. To achieve such a global goal, we covalently linked, by an amidation reaction, the terminal NH, of Emeraldine (EB) and sulfonated Emeraldine (SPAN) to a free carboxylic group belonging to the repetitive unit of a functionalized segmented polyurethane. The reaction was carried out by activating such a carboxylic group with N,N'-dicyclohexylearbodiimide and N-hydroxysuccinimide. The reaction yields and the chemical properties of the polymers were studied by proton and carbon-13 nuclear magnetic resonance, ultraviolet, and Fourier transform infrared spectroscopy. The average numbers of EB or SPAN aromatic rings per polyether urethane acid (PEUA) repetitive unit, which cannot be assumed to be amidation degree because at this moment the molecular weights of the inserted EB and SPAN chains are unavailable, were 6 in case of the polymer obtained from the pristine Emeraldine and 1 for that obtained from the sulfonated Emeraldine. This result could be because SPAN was used in the acidic form, which depresses the nucleophilicity of the NH, group because of the presence of the sulfonic protons.