The Mechanical Characterization of Multi-Wall Carbon Nanotubes andRelated Interfaces in Nanocomposites

摘要

This thesis primarily documents the development and application of a noveltechnique, which involves the usage of a silicon micro-mechanical device that operates inconjunction with a quantitative nanoindenter within an electron microscope, for themechanical characterization of nanomaterials and interfaces in composites. The techniquewas used to conducted tensile tests on individual pristine, nitrogen doped and sidewallfluorinated multi-wall carbon nanotubes (MWNTs), which were found to exhibit variedload-bearing abilities and unique fracture modes. The technique was also used to performsingle fiber pullout experiments to study the MWNT/polymer (epoxy) interface.Interfacial failure was found to occur in a brittle fashion, in a manner consistent with thepredictions of continuum fracture mechanics models. Although an improvement in theinterfacial adhesion was observed upon sidewall fluorination of the MWNTreinforcements, the results of the study essentially highlighted the weak nature of theforces that bind MWNTs to an epoxy matrix.