The development of a new class of alternative plastics has been encouraged in the past few years due to the serious environmental issues, such as toxicity and carbon dioxide emissions. Hence, the introduction of renewable, biodegradable, and biocompatible materials is becoming critical as substituents of conventional synthetic plastics. To design a new system of novel TEMPO-oxidized cellulose nanofibrils (TOCNs)/graphene oxide (GO) composite, the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was utilized to disintegrate never-dried wood nanofibrillated cellulose (NFC). GO was incorporated through high intensity homogenization and ultrasonication with varying degree of oxidation (0.5X, 1X, and 2X) of NFC and GO percent loadings: 0.4, 1.2, and 2.0wt %. As a result, despite the presence of carboxylate groups and graphene oxide (GO), X-ray diffraction (XRD) test showed the crystallinity of the bio-nanocomposite was not altered. Scanning electron microscopy (SEM) was used to characterize their morphologies. In addition, the thermal stability of TOCN/GO composite decreased upon oxidation level, and dynamic mechanical analysis (DMA) signified strong intermolecular interactions with the improvement in Young's storage modulus, and tensile strength. Fourier transform infrared spectroscopy (FTIR) was employed to see the hydrogen bonds between GO and cellulosic polymer matrix. The oxygen transmission rate (OTR) of TOCN/GO composite decreased. The water vapor permeability (WVP) was not significantly affected by the reinforcement with GO, but the moderate oxidation enhanced the barrier properties. Ultimately, the newly fabricated TOCN/GO composite can be utilized in a wide range of life science applications, such as food and medical industries. / Master of Science / In recent years, petroleum-based polyolefins have been contributing to severe environmental issues. With this in perspective, the development of a new class of alternative plastics has been encouraged. Hence, the introduction of renewable, biodegradable, and biocompatible materials is becoming critical as a substitute for non-degradable synthetic plastics. In this study, a new system of novel cellulose-based plastic composites was designed by incorporating carbon nanofillers at various percent loadings and different degree of surface modification of the plastics. These treatments are the economical way to achieve the targeted properties for industrial applications, exhibiting the obvious improvement in tensile strength due to the strong interaction between nanofillers and cellulose. In addition, water vapor and oxygen barrier properties play significant roles in food packaging since food decay is vulnerable to these two factors. The barrier performance was enhanced by hindering the permeation of oxygen gases, whereas the water vapor permeability was not significantly affected by the reinforcement with carbon nanofillers. Ultimately, the newly fabricated cellulose plastic can be utilized in various applications, especially, such as the pharmaceutical and biomedical areas, packaging for food and goods, and agriculture due to their high availability, sustainability, and biodegradability.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/85177 |
| Date | 15 December 2017 |
| Creators | Kim, Yoojin |
| Contributors | Macromolecular Science and Engineering, Kim, Young Teck, Edgar, Kevin J., Roman, Maren |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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