NSF Award
9560642
This Small Business Innovation Research Phase I project is aimed at developing an understanding of and modifications to the surface state, surface chemistry, and development of sizings for vapor-grown carbon fibers for interface control in composites. In contrast to brittle matrix composites, polymer matrix composites generally require a high degree of fiber-matrix adhesion in order to provide good composite strength and toughness. The majority of commercial reinforcing fibers, both carbon and glass, are treated during or after manufacture with various surface treatments as well as a sizing to increase compatibility with and bonding to the matrix polymer. A new class of carbon fiber has been developed and is being produced in pilot scale quantities. This vapor-grown carbon fiber (VGCF) holds the promise of a highly graphitic fiber reinforcement at costs significantly lower than other carbon fibers. However, due to the high graphitization of this fiber, the fiber surface is generally unreactive and will not bond with polymer matrices. Thus, various treatments will be evaluated for their effect in enabling fiber/matrix bonding in polymer matrix composites. Specifically, various degrees of surface oxidation will be effected onto the fibers followed by application of commercial sizings. The surface chemistry will be quantified and also verified from composite testing. As a low cost fiber, VGCF can potentially be used as a composite reinforcement for many elastomeric and polymeric matrices. The solution of the problem of low fiber-matrix adhesion will allow for the development of, at least one, commercially viable material for use in automotive parts, materials requiring EMI shielding, and innovative composites requiring small diameter fibers.
