Date

2022-1-23

Author

Budak, Deniz

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Control of interfacial interactions is essential for the preparation of polymer matrix composites with enhanced physical, mechanical, thermal and electrical properties. The performance of the graphene and graphene oxide (GO) additives can be improved by achieving strong adhesion and uniform dispersion of GO in the epoxy matrix. In this study, modeling and simulation of DGEBA (Bisphenol A diglycidyl ether)/DETA (Diethylenetriamine) based epoxy nanocomposites containing graphene and graphene oxide (GO) additives were performed. Density functional theory and classical mechanics methods were used to investigate interaction energies and Young’s Modulus values in the nanocomposite system. The objective of this study is to demonstrate the role of the amount, ratio and type of functional groups on the interaction energy and Young’s modulus values. Improvement in the interaction energies was studied by controlling the epoxy:hardener ratio, type and the number of oxygen-containing functional groups on the GO, mass percentage of filler in epoxy, size of GO and dispersion in the cell. It was founded that functional groups with up to 10% oxygen coverage significantly increase interaction energy, and after there is only a slight enhancement of up to 18% oxygen. However, when DETA:DGEBA ratio in epoxy resin molecules was changed, a different trend was observed for a single layer GO. For the low oxygen ratio on GO, increasing amine groups of DETA decreases the interaction energy. Carboxylic acid and hydroxyl groups on GO are important groups for increasing the hydrogen bonds and affinity with the epoxy matrix. Epoxy and hydroxyl groups are main groups that enhance the dispersion of the GO. Hydroxyl groups in the epoxy chain perform better than the amine groups in the epoxy chain to form hydrogen bonds with GO surface.

Subject Keywords

Epoxy, Graphene, Graphene Oxide, Nanocomposites, Molecular Dynamics Simulations

URI

https://hdl.handle.net/11511/102056

Collections

Graduate School of Natural and Applied Sciences, Thesis