Polymerisation of methyl ethyl ketone formaldehyde resin modified with carbazole-9-carbonyl chloride

Purpose ‐ The purpose of this paper is to obtain a conductive polymer by using a fluorescence comonomer which is an insulator. In this study, methyl ethyl ketone formaldehyde resin (MEKFR) modified with carbazole-9-carbonyl chloride (CzCl) was synthesised via hydroxyl groups of MEKFR. Electrochemical polymerisation of Cz-MEKFR comonomer was carried out potentiostatically and a green, conductive polymer P(Cz-MEKFR) was obtained. The advantages of obtaining alternative structure of P(Cz-MEKFR) to the random copolymer were reported. Design/methodology/approach ‐ Cz-MEKFR comonomer was synthesised by the esterification reaction of CzCl and hydroxyl groups of MEKFR. Then, for the electrochemical polymerisation, potentiodynamic electrodeposition of Cz-MEKFR comonomer in dichloromethane on to Pt was carried out. Electrochemical activities of polymers were tested by electrochemical methods (i.e. polarization curves and cyclovoltammetry). UV-visible, NMR, polarization curves, cyclovoltammetric, solid-state conductivity measurements and in situ spectroelectrochemical methods were performed for the characterization of polymers. Findings ‐ Carbazole-9-carbonyl chloride(CzCl) modified MEKFR was synthesised. This new carbazole-modified resin (Cz-MEKFR comonomer) has fluorescence property. The ionization potentials (Ip), electron affinity (Ea), optical band gap (Eg), peak potentials (Ep) and doping degree (y) of the polymers were calculated. Results were compared with the PCz homopolymer and the copolymer obtained from the mixture of MEKFR with carbazole P(Cz-co-MEKFR). Research limitations/implications ‐ This study focuses on obtaining a conductive polymer by using a fluorescence comonomer which is an insulator. In order to remove pyridine from comonomer, successively washing with several portions of dilute aqueous H₂SO₄, water-saturated aqueous sodium hydrogen carbonate, and hot water is necessary. Practical implications ‐ This work provides technical information for the synthesis of fluorescence comonomer and conducting an alternative polymer. Originality/value ‐ A new Cz-CFR comonomer was synthesised. This comonomer has a higher T_m value than MEKFR alone and also has fluorescence property. The band gap of the copolymer is not remarkably lower than polycarbazole. The oxidation potential of P(Cz-MEKFR) was found to be higher than the PCz homopolymer and the solubility of copolymer is 30 per cent higher than homopolymer.