Dissertation
PROCESSING AND PROEPRTIES OF NOVEL GRAPHENE-BASED PLA BIONANOCOMPOSITES
Doctor of Philosophy (PhD), Washington State University
01/2013
Handle:
https://hdl.handle.net/2376/111856
Abstract
In this study a novel graphene-based PLA bionanocomposite was prepared and investigated in the experiments in details.
The experimental results indicated that the resulting bionanocomposites with maleated PLA exhibited higher mechanical, rheological, and better electrical properties as compared to neat PLA and the bionanocomposites without maleated. In addition, the thermal and thermally mechanical properties of the resulting bionanocomposites were to some degree improved in comparison with neat PLA.
A novel one-step approach was developed for the pH-triggered electrochemically interacted exfoliation of graphene sheets in graphite oxide and simultaneous reduction and functionalization with the aid of the ionic liquid. The results indicated that, with the aid of the IL during the reaction, the resulting functionalized graphene showed improved organophilicity, wettability, interfacial interactions, as well as significant resistance to thermal degradation.
A binary PLA blend system has been chosen as nanocompsoite matrix to not only achieve enhanced interfacial interactions between graphene and PLA, but also overcome the inherent drawbacks of the PLA matrix such as its brittleness. The functionalized graphene with reactive groups were possibly covalently crosslinked with the PLA through a second phase, EBA-GMA. The resulting three-dimension network structures were finally generated in the system and they brought about the improved viscoelasticity and thermal stability.
A comprehensive discussion was made on the effects of functionalized graphene on interface, crystallization, and electrical properties of the toughened PLA blends. The TEM analysis indicated that the GO particles almost predominantly dispersed in the PLA, but the silane-functionalized graphene preferentially located in the rubber phase or at the PLA/EBA-GMA interfaces concentratedly, especially for the functionalized graphene with reactive functional groups. The results of DSC analysis showed that f-GO played a key role in improving the cold crystallization temperature of the PLA blend. The improved electrical conductivity and dielectric properties of the f-GO nanocomposites reflected the structure continuity of the matrix phase and the formation of a 3-D effective conductive network compared to the blend matrix and GO nanocomposite.
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Details
- Title
- PROCESSING AND PROEPRTIES OF NOVEL GRAPHENE-BASED PLA BIONANOCOMPOSITES
- Creators
- Yu Fu
- Contributors
- Jinwen Zhang (Advisor)Weihong Katie Zhong (Committee Member)David P. Field (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 170
- Identifiers
- 99900581448001842
- Language
- English
- Resource Type
- Dissertation