Paper number 772


Michael J. Rich, Shawn Corbin, and Lawrence T. Drzal

Composite Materials and Structures Center, College of Engineering, 2100 Engineering Building, Michigan State University, East Lansing, Michigan, USA 48824-1226

Summary In this study, chemical and physical factors governing adhesion were investigated to determine the underlying cause for inadequate fiber-matrix bonding between carbon fibers and vinyl ester polymers. Scanning tunneling microscopy of a family of fibers differing only in the level of surface treatment showed that surface roughness is minimized at the standard 100% treatment level and increases at treatment levels greater than 100%. A series of experiments where carbon fibers were exposed, individually or in combinations, to the vinyl ester initiator, accelerator, promoter, or catalyst found preferential adsorption of some of these constituents on the fiber surface, which could lead to an interphase having properties different than the polymer bulk properties. Two micromechanical test methods, microindentation and fiber fragmentation, were employed to quantify the level of adhesion between carbon fibers and vinyl ester matrix. Application of a fiber sizing was found to increase the level of adhesion and improve mechanical properties of carbon fiber-vinyl ester composites.
Keywords carbon fibers, vinyl ester, fiber-matrix adhesion, sizing, coating.

Theme : Interface and Interphase

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