Chemical modification of carbon fibres by esterification - optimization of fibre pretreatment

Electrochemically oxidized PAN-based carbon fibres were modified by attachment of an m-dinitrobenzene group. Chemical modification was performed by esterification of the -OH groups of the oxidized carbon surface with 3,5-dinitrobenzoyl chloride. The higher modification extent was achieved in the case of d.c. oxidized carbon fibres, which bear a large number of -OH groups. The attachment of the dinitrobenze species was supported by cyclic voltammetry carried out on the modified carbon fibre electrodes in aqueous solutions. The quantity of attached m-dinitrobenzene groups was determined polarographically, after hydrolysis of the esteric bonds; it corresponds to a charge density of ca 0.2 kAh kg-1 carbon fibres, which is of the order of magnitude of battery electrodes.