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'-benzophe nonetetracarboxylic dianhydride (BTDA), 4,4'-oxydianiline (ODA) and 1.3-phe nylenediamine (PDA) was performed from a nonaqueous emulsion on carbon fibe rs. The electrodeposited PAA was subsequently dried. The yield and quality of deposited polyamic acid are strongly dependent upon a number of paramete rs that are related to the formulation and characteristics of polyamic acid emulsion. These parameters include solvent/precipitant ratio, concentratio n of surfactant, and solids content. The deposition yield of PAA was relate d to the applied current density, deposition time, and the charge passed, a nd was found to obey Faraday's laws of electrolysis. The coulombic efficien cy was calculated.