CHARACTERIZATION OF ELECTROPOLYMERIZED GRAPHITE FIBER POLYACRYLAMIDE COMPOSITES

The synthesis of a series of graphite fiber-polyacrylamide composites was performed electrochemically in dilute sulfuric acid (0.125M) -acrylamide (2M) solution, 1 : 1 sulfuric acid (0.25M) : acetone-acrylamide (2M) solution, and 1 : 1 sulfuric acid (0.25M) : 2-propanol-acrylamide (2M) solution, respectively, using graphite fiber bundles as the working electrode. The graphite fiber-polyacrylamide composites, synthesized in a 1 : 1 2-propanol : sulfuric acid-acrylamide solution, were more easily characterized than those synthesized from the sulfuric acid-acrylamide solution that contained no alcohol. Composites that were synthesized in a dilute sulfuric acid solution were, however, more readily crosslinked. (Fourier transform infrared spectroscopy, FTIR, confirmed the formation of interchain and intrachain imide functional groups after the resin was cured at approximately 200-degrees-C.) Polymer weight gain analysis, coupled with surface morphology studies using scanning electron microscopy, showed that the thickness of the coatings, and hence the volume fraction of the resin in the composites, varied linearly with the time of electropolymerization. Scanning electron microscopy revealed an open and folded chain surface structure, which permitted unrestricted permeation of the monomer onto the electrode surface. Differential scanning calorimetry of the electropolymerized resins confirmed a glass transition temperature of between 180 and 207-degrees-C. (C) 1994 John Wiley & Sons, Inc.