Functionalized Double-Walled Nanotubes for High Performance Composites

It is proposed to incorporate functionalized double-walled carbon nanotube fillers into high-performance epoxy and vinyl ester resins as a means of substantially improving mechanical properties of the resulting nanocomposite materials. Covalent functionalization of only outer tube wall will leave the inner tube intact, thus preserving the exceptionally high mechanical properties of a DWNT to a maximum possible degree. Functionalization strategy is directed towards finding functional groups that provide the best compatibility and bonding with the structural resins of interest. This would eventually result in perfect dispersion of DWNTs in the resin and much improved load transfer between the tube and the matrix. These parameters will be characterized with electron microscopy and various spectroscopy techniques, which provide a better insight into the structure and functioning of the interface layer and lay grounds for an understanding the effects that the functional groups have on the mechanical properties of nanocomposites. By measuring the mechanical properties of the DWNT composites on the macro- and micro-level, and correlating them to the type and degree of functionalization, the optimum functional group and manufacturing procedure for resins of interest will be selected for in-depth exploration during Phase II. Comparative studies of functionalization of DWNTs and SWNTs and of mechanical performance of corresponding nanocomposites will be performed to analyze the feasibility of the proposed approach. BENEFITS: If the project is successful and is carried out into Phases II and III, the greatest benefits are expected for the NAVY PMS 500 Destroyer Class Program where exceptionally strong and marine environment stable epoxy and vinyl ester composites are needed. This need presents new challenges and opportunities to the research and technology development efforts, one of which is in designing the advanced composite materials based on nanotube fillers and should be successful in the present project by means of functionalized DWNT incorporation in resins of interest. This anticipation is based, in part, on very promising results in terms of mechanical properties obtained recently at MER Corporation with polyethylene DWNT composites. Due to very large market for polymer composite materials and growing demand for their high performance in the military and civil sector, the significant improvement in mechanical properties expected from functionalized DWNT involvement would have easily find a niche in various applications, including commercial shipbuilding, construction, automobile, aviation and space, and sporting goods industries. Thus, this program could have significant technical, economical and social benefits to the Nation.