Reactive Finish Formulation for Improving Interfacial Bonding in Carbon/Vinyl Ester Composites

The interface is often a limiting factor in determining the durability of composite materials used in harsh environments. Attaining a well-bonded interface is particularly difficult with low-temperature curing matrix resin systems. A need exists for a carbon fiber adhesion promoting finish that is compatible with vinyl ester chemistry. Prior work using reactive coupling agent chemistries modified to function with vinyl ester moieties cures showed that the modified reactive finishes allow control of interfacial adhesion in these composite systems. The reactive finishes provide superior interface dominated mechanical properties and are compatible with resin infusion processing. Carbon/vinyl ester composites fabricated with the reactive finishes are also expected to exhibit improved environmental durability due to the improved interfacial bonding. The reactive finishes to date have been applied from organic solvents. Before these chemistries can be applied on a large scale by carbon fiber manufacturers, they must be formulated into water-based systems. Once that is accomplished, then the finish must be optimized for compatibility with vinyl ester resins, resin infusion techniques, and weaving processes. These areas and the development of an extensive composite properties database, including durability testing, are proposed to be addressed.