Electrodeposition of BTDB-ODA-PDA polyamic acid coatings on carbon fibers from nonaqueous emulsions

Electrochemical deposition of polyamic acid copolymer of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 4,4'-oxydianiline (ODA) and 1.3-phenylenediamine (PDA) was performed from a nonaqueous emulsion on carbon fibers. The electrodeposited PAA was subsequently dried. The yield and quality of deposited polyamic acid are strongly dependent upon a number of parameters that are related to the formulation and characteristics of polyamic acid emulsion. These parameters include solvent/precipitant ratio, concentration of surfactant, and solids content. The deposition yield of PAA was related to the applied current density, deposition time, and the charge passed, and was found to obey Faraday's laws of electrolysis. The coulombic efficiency was calculated.