Degradation of Graphite/Polymer Composites in Seawater

Abstract

Glass-reinforced plastics have a substantial history of use in seawater. With the advent of high-performance graphite fibers offering greater stiffness than glass, some marine engineering applications may be implemented where glass was unsuitable. However, the nobility of graphite in the galvanic series makes it an extremley efficient cathode when copuled with metals in seawater. Degradation of the cathodic composite material is an unexpected result of the corrosion chemistry in natural seawater. Deep submergence of composite materials introduces another potential degradative mechaism in seawater due to an increased moisture uptake by damage-dependent mechanisms. Other environmental exposure to sunlight, deep submergence and cyclic thermal changes which show potential for degradation of composites are discussed.