Text

theses

ETD doctoral

Graphene has been publicized as the next generation material of this millennium. In the past two decades, the 2D material has been researched for use in such applications as thermal management, environmental remediation, biotechnology, and lightweight, structural materials, due to its exceptional mechanical properties. Exfoliation methods have already been developed for the production of un-oxidized graphene flakes, including electrochemistry, chemical oxidation and expansion, and liquid phase synthesis. All these approaches eventually yield graphene, but at a tremendous sacrifice to cost, process complexity, and desired properties. Majority of these methods create graphene by the use of a multistep processes, and produce harmful byproducts due to extraction from wasted matrices. As a consequence, defects are often introduced within the surface, which greatly diminish their properties. The key challenge is finding a de-convoluted process competitive enough to reduce cost and maintain pristine structure through all developing stages.

Under high speed extensional flow of graphite and a high polymer matrix, the conditions to fully convert many layered graphite to graphene can be done in-situ. A novel process invented by Nosker et al., using extensional flow, allows for a polymer matrix and graphitic filler to undergo unique deformations of extension and exfoliation, respectively. Based on the experimental conditions, the polymer experiences a transition from a complex random walk network of chains to a fully stretched detangled array with an elongated conformation. This results in a polymer with an increase in potential energy and exposure of its chemical side groups. Under the same field, the graphite undergoes an exfoliation mechanism dominated by free radicalization via erosion, fragmentation, and diffusion leading to few and many layer graphene flakes. These conditions create two or more high surface areas, in-situ, that provided functionalization of chemically desirable sights. The process herein, yields a scalable method of producing functionalized graphene with unique properties by a continuous mixing process. Within this work, an experimental study of the complex phenomena undergone by both the polymer and created graphene are investigate. Analyzing a combination of the mixing process, composite interface, and morphology we will seek to expand our knowledge on new complex graphene composite systems.

ETD_11257

Ph.D.

Includes bibliographical references

doi:10.7282/t3-g7h5-cs16

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