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Carbon nanotube/epoxy nanocomposites effect of interfacial chemistry and processing on molecular mobility, cure behavior, morphology and properties /Abdalla, Mohamed A. January 2008 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2008. / Additional advisors: Gregg M. Janowksi, Tamara Floyd Smith, Gregory B. Thompson, Uday Vaidya. Description based on contents viewed July 7, 2009; title from PDF t.p. Includes bibliographical references.
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Effect of carbon filler characteristics on the electrical properties of conductive polymer composites possessing segregated network microstructuresPrystaj, Laurissa Alia 31 July 2008 (has links)
This thesis focused on making composites consisting of a polymethylmethacrylate matrix, with various carbon fillers. The fillers that were examined were 3 different carbon blacks: N-550, N-772 and pureblack, and short multi-wall carbon nano-tubes. The carbon fillers were coated onto the polymethylmethacrylate, and compression molded in order to form a segregated microstructure. The goal of this thesis is to compare the electrical and optical properties of the composites consisting of a segregated microstructure, containing various carbon fillers.
Scanning electron microscopy was used to investigate the fracture surface of the composites. Impedance Spectroscopy measured the electrical response of the material, and was used to determine the conductivity and dielectric properties of the composites and estimate the percolation threshold. The multi-wall carbon nano-tubes were found to have the lowest percolation threshold, due to their rod like structure. All of the carbon black fillers displayed similar characteristics in their conductivity and dielectric properties. As the filler content increased, the conductivity and the dielectric constant of the composites increased.
Optical absorption measurements determined the amount of light that travel through the specimen. These measurements, showed that the absorbance for the carbon black sample N-550 were lower than the multi-wall carbon nano-tubes at filler contents below a phr of 0.1 The absorption of the carbon black samples was then higher than multi-wall carbon nano-tubes at phrs higher than 0.1. This was found to be related to the nano-tubes starting to form a segregated microstructure at lower filler contents than the sphere-like carbon black nano-particles.
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Polymer composites incorporating engineered electrospun fibres : flexible design and novel properties for biomedical applicationsZhang, Xi January 2017 (has links)
Due to their unique structure and flexible choice of materials, electrospun degradable and biocompatible polymer fibres are considered to be extremely suitable for biomedical applications such as tissue engineering and drug delivery, either on their own or integrated within composites. Conventional electrospun fibre composites are typically based on non-woven mats and therefore limited to simple-curved geometries (films, membranes, etc.). For aqueous composites such as hydrogels, the hydrophobicity of the materials sometimes prohibits fibres to be easily integrated or distributed in these composites. In this thesis, a review on the topic is firstly presented in Chapter 2, introducing and discussing engineering of electrospun fibre as well as their biomedical applications. In Chapter 3, electrospun polylactide (PLA) fibres reinforced poly(trimethylene carbonate) (PTMC) composites are prepared. The composites are loaded with both continuous and short PLA fibres, achieving significant mechanical enhancement and offering opportunities to produce composites conveniently using liquid formulations. Chapter 4 presents the development of shape memory polymer composites based on a combination of PLA fibres and a PTMC matrix. By loading different amounts of short fibres with different aspect ratios or by using plasticisers, the shape memory behaviour is modulated; and composites of more complex geometries are produced. In Chapter 5, PTMC-PLA fibre composites are made into drug release system. Dexamethasone-loaded PLA fibres are integrated into a PTMC matrix, showing sustained drug release and stimulating stem cell osteogenic differentiation. This concept gives promise to loading various drugs into photo-crosslinked structures without denaturation. In Chapter 6, electrospun PLA fibres are functionalized by amphiphilic block copolymer polylactide-block-poly[2-(dimethylamino)ethyl methacrylate] (PLA-b-PDMAEMA) for the development of carboxymethylcellulose composites hydrogels. Functionalization of PLA fibres not only allows for easy integration and dispersion into the hydrogel, but also enhances the interfacial bonding between fibre and hydrogel. In the last chapter (Chapter 7), some conclusions are drawn and future works are discussed.
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The Design and Synthesis of Aromatic Ion-Based Polyelectrolytes for Divergent ApplicationsFreyer, Jessica Leigh January 2018 (has links)
Versatile polyelectrolytes with tunable physical properties have the potential to be transformative in applications ranging from medicine to energy storage. To expand the design space for innovative cationic polymeric materials, I describe herein the development of a new class of functional polyelectrolyte based on the aromatic trisaminocyclopropenium (TAC) ion. The facile synthesis of a series of cyclopropeniumbased macromolecules via either the direct polymerization of functional monomers or a post-polymerization click reaction is demonstrated. To probe fundamental structureproperty relationships and understand technological implications of cyclopropenium polymers, a variety of materials were evaluated as gene delivery agents for cellular transfection and as ion conducting membranes. It was found that certain cyclopropenium polymers are biocompatible and efficient transfection agents, and that post polymerization functionalization chemistry enabled the straightforward screening of polymeric TAC derivatives. Furthermore, the thermal properties, local morphology, and dielectric response of a series of monomeric and polymeric TAC ionic liquids with different counter ions were characterized. It was found that the mechanism for ion transport depends on the nature of the ion pair, which can promote anomalously high conductivity at the calorimetric glass transition temperature. Finally, the synthesis of a new class of polyelectrolyte based on the cyclopentadienyl aromatic anion is described.
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Erosive wear resistance of carbon nanotube reinforced epoxy compositesChen, Jinhu January 2014 (has links)
No description available.
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Characterization of cryogenic microcracking in carbon fiber/epoxy composite materials /Timmerman, John Francis, January 2003 (has links)
Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 119-128).
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Role of nano-particles on crystalline orientation in polypropylene/clay nanocomposite filmsWoods, Courtney G., January 2003 (has links) (PDF)
Thesis (M.S. in Ch. E.)--School of Chemical Engineering, Georgia Institute of Technology, 2004. Directed by John D. Muzzy. / Includes bibliographical references.
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Boron containing vinyl aromatic polymers synthesis, characterization and applications /Parab, Kshitij K. January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Chemistry." Includes bibliographical references (p. 146-161).
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Improved durability and thermal stability of glass fiber reinforced composites using clay-polymer nanocomposites /Liu, Mingyang. January 2009 (has links)
Includes bibliographical references (p. 80-83).
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Application of fictitious domain method to analysis of composite materials /Podnos, Eugene Grigorievich, January 1999 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 93-100). Available also in a digital version from Dissertation Abstracts.
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