| dc.description.abstract | One-dimensional nanomaterials, such as carbon nanotubes (CNTs) and nanowires, are promising for various applications. Although CNTs have been used as reinforcements in composites owing to their high mechanical strength and high surface-area-to-volume ratio, the use of nanowires as reinforcements has not been examined extensively. This is especially surprising, given that nanowires have not only been successfully synthesized, but also demonstrated to exhibit novel mechanical properties. One of the challenges for the applications of nanowires is that translating the successes achieved in the laboratory to commercial products requires mass production of nanowires, if possible, in a byproduct-free manner. In view of this, the first objective of this dissertation is to produce byproduct-free nanowires. This was accomplished using Zn3P2 nanowires as an illustration. Herein, Zn foams were obtained and used as substrates to grow Zn3P2 nanowires. These foams were obtained in situ by heating consolidated mixtures of Zn flakes and a sacrificial salt, NH4Cl. This approach aided in the uniform heating of the foams and the complete conversion of Zn into Zn3P2 nanowires.
The second objective is aimed at the fabrication of nanowire-based composites and examination of the effects of nanowires on the mechanical properties of nanocomposites. Herein, Zn3P2 and TiO2 nanowires were selected as reinforcements. To understand nanowire-epoxy interaction, various coupling agents were applied to nanowires to modify their surface characteristics. Overall, functionalization affected both interfacial adhesion and the degree of dispersion of nanowires. Ultimately, this was observed to alter the mechanical properties of these nanocomposites.
Lastly, to fabricate nanocomposites in a manner similar to that employed for fiber-reinforced composites, foams of interconnected nanowires were prepared by heating the functionalized nanowire mixtures with sacrificial salt microcrystals. The idea here is that optimal mechanical performance of nanocomposites is achieved when a continuous filler network is established, while preventing nanowire agglomeration. These nanowire foams were infused with a shape memory polymer (SMP) and the mechanical properties of the resulting composites were studied. These composites exhibited mechanical properties superior to those obtained by merely mixing fillers and a matrix material. | en |
