Improved Interface and Mechanical Properties in High Modulus Carbon Fiber Reinforced Vinyl Ester Composite Laminates

The objective of this proposal is to develop and demonstrate the feasibility of high modulus carbon fiber reinforced, VARTM processable vinyl ester laminates with an improved fiber / matrix interface that will provide increased modulus and other mechanical properties. The appropriate choice of resin will also provide composite structures with reduced flammability, smoke and toxicity. The goal is to produce a fiber sizing that will be applied in a conventional carbon fiber manufacturing process and improve adhesion between the high modulus reinforcing fiber and the vinyl ester resin when cured in a VARTM process. We propose to achieve this improvement in interfacial bonding by sizing the fiber with a combination of a polymeric film former and a coupling agent. The degree of adhesion between the fibers and the matrix as well as the nature of the fiber / matrix interphase have a major influence on the mechanical properties and the durability of a composite. Significant interfacial adhesion is required to obtain effective stress transfer from the matrix to the load bearing reinforcing fibers. If the interfacial adhesion between carbon fiber and vinyl ester resin could be improved then the full potential of these advanced composites could be realized.