| dc.description.abstract | Nanoscale fillers blended with polymers (“nanocomposites”) offer the real possibility of creating materials with properties that are not realizable with traditional, micron-scale fillers. In order to improve the performance of polymer nanocomposites, attempts have been undertaken to enhance the properties of both fillers and the polymer matrix. However, an important but hidden factor for developing high performance polymer nanocomposites is understanding and controlling the filler/matrix interfacial region. The overall objective of my dissertation is to develop new approaches to manipulate the interface of the nanocomposites, study the role of the interface in influencing mechanical behavior of polymer nanocomposites, and fabricate high performance and multi-functional polymer nanocomposites.
Our study first focuses on studying the role of the interfacial region on the fracture behavior of the polymer nanocomposites. A set of model systems based on polymethylmethacrylate (PMMA) matrix containing polymer brushes grafted on metal-organic-framework (MOF) nanoparticles were synthesized and investigated. By systematically adjusting the polymer brush length and graft density on MOF nanoparticles, the fracture behavior of PMMA/MOF nanocomposite is found to change from forming a few big crazes to massing crazing, and to significant shear banding, which results in significant improvement in fracture toughness. The implication of the present finding for the design of high performance, multi-functional polymer nanocomposites is discussed.
The nanoscale particles typically aggregate, which negates any benefits associated with the nanoscopic dimension. There is a critical need for establishing processing techniques that are effective on the nanoscale yet are applicable to macroscopic processing. A new strategy to prepare self-curing epoxy nanocomposites has been proposed. Epoxy can be cured by the nanoparticles without the addition of curing agents, by taking the advantages of the surface chemistry of the nanoparticles. Three types of self-curing epoxy nanocomposites containing MOF, MOF decorated carbon nanotubes, and zirconium phosphate are prepared to achieve multi-functional polymer nanocomposites. The simple process can be easily scaled up to produce nanocomposites. | |
