Pigment & Resin Technology
Belkis Ustamehmetoğlu, Ahmet Akar, Nilgun Kizilcan, Eda Kelleboz
The purpose of this paper is to develop the soluble and processable conducting copolymers of carbazole (Cz), ethylcarbazole (ECz), Nvinylcarbazole (NVCz) by oxidatively polymerising carbazoles by ceric ammonium nitrate (CAN) in the presence of methyl ethyl ketone formaldehyde resin (MEKFR); and to report the advantages of obtaining copolymer structure. A new class of soluble and conductive P(Cz/MEKFR), P(NVCz/MEKFR) and P(ECz/MEKFR) copolymers were synthesised by the method of oxidative polymerisation with ceric ammonium nitrate. MEKFR, CAN and carbazole monomers (Cz, NVCz and ECz) were dissolved in acetonitrile separately. Then, the CAN solution was added dropwise into the mixture of MEKFR and Cz, NVCz or ECz solutions while stirring and a green powder was formed almost instantaneously. After one hour stirring at 25°C, the powder was filtered, washed with acetonitrile and dried at room temperature. A green coloured product was obtained. The colourless insulator copolymer present in this product was separated by selectively dissolving with toluene. The insoluble green copolymer was filtered off and dried at room temperature under vacuum. The products were characterised by FTIR, DSC thermograms, 1HNMR, fourpoint probe conductivity and atomic absorption measurements. The solubility and conductivity of the Cz/MEKFR copolymer P(Cz/MEKFR), the NVCz/MEKFR copolymer P(NVCz/MEKFR) and the ECz/MEKFR copolymer P(ECz/MEKFR) were regulated by the ratios of (Cz, NVCz, ECz)/CAN/MEKFR. By inclusion of the ketonic resin segments to the polycarbazole chains, thermally processable copolymers have been obtained with a melting point of about 80°C. FTIR results in different reaction time and the presence of metal in copolymers show together a complex between monomermetal and resin.