Carbon nanotube-reinforced composites: Processing, characterization and modeling

The exceptionally high specific stiffness and strengths reported for carbon nanotubes, combined with their fiber-like structure, has stimulated research in the development of polymer nanocomposites reinforced with carbon nanotubes. Before these extraordinary properties observed at the nano-scale are realized in a macroscopic composite, considerable basic research is necessary. This research work seeks to obtain a fundamental understanding of the processing/structure/property relations in carbon nanotube-reinforced composites through integrated research on processing and characterization of model nanocomposite systems as well as development of predictive models for the nanocomposite elastic properties. Ultimately, establishment of these basic relationships will enable the nanoscale design of nanotube-reinforced materials.; In this work, a novel technique to produce continuous nanocomposite ribbons of aligned multi-walled carbon nanotubes embedded in a polystyrene thermoplastic matrix was developed. This model nanocomposite system serves as a basis for the investigation of structure/property relationships through characterization of their elastic and fracture behavior. Based on characterization results and numerical simulations, a micromechanics-based modeling technique is developed to describe the structure/size influence of the nanotube reinforcement on the elastic modulus of these nanocomposites. To reveal the hierarchy of nanotube reinforcement, multi-scale hybrid composites, where a nanotube composite sheath surrounds traditional carbon fibers, were produced and the influence of selective reinforcement on load transfer at the fiber/matrix interface was examined.