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Description
Carbon nanotube (CNT) membranes (buckypaper) are manufactured with multiple procedures, vacuum filtration, surfactant-free, and 3D printing. A post-manufacturing process for resin impregnation is subjected to the membranes. The effects of manufacturing processes on the microstructure and material properties are investigated for both pristine and resin saturated samples manufactured using all procedures. Microstructural characteristics that are studied include specific surface area, porosity, pore size distribution, density, and permeability. Scanning electron microscopy is used to characterize the morphology of the membrane. Brunauer-Emmett-Teller analysis is conducted on membrane samples to determine the specific surface area. Barrett-Joyner-Halenda analysis is conducted on membrane samples to determine pore characteristics. Once the microstructure is characterized for each manufacturing process for both pristine and resin saturated samples, material properties of the membrane and nanocomposite structures are explored and compared on a manufacturing basis as well as a microstructural basis. Membranes samples are interleaved in the overlap of carbon fiber polymer matrix composite tubes, which are subjected to fracture testing. The effects of carbon nanotube membrane manufacturing technology on the fracture properties of nanocomposite structures with tubular geometries are explored. In parallel, the influences of manufacturing technology on the electromechanical properties of the membrane that effect a piezoresistive response are investigated for both pristine and resin saturated membranes manufactured using both methods. The result of this study is a better understanding of the relationships between manufacturing technology and the effected microstructure, and the resulting influences on material properties for both CNT membranes and derivative nanocomposite structures. Developing an understanding of these multiscale relationships leads to an increased capacity in designing manufacturing processes specific to optimizing the expression of desired characteristics for any given application.
ContributorsWoodward, John Michael (Author) / Chattopadhyay, Aditi (Thesis director) / Yekani Fard, Masoud (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Poly(ionic liquid)s (PILs) with an intrinsically conducting pyrrole polymer (ICP) backbone were synthesized and utilized as novel dispersants of carbon nanotubes (CNTs) in various polar and nonpolar solvents. This is due to their highly tunable nature, in which the anions can be easily exchanged to form PILs of varying polarity but with the same polycation. These CNT dispersions were exceedingly stable over many months, and with the addition of hexane, Pickering emulsions with the PIL-stabilized CNTs at the droplet interfaces were formed. Depending on the hydrophobicity of the PIL, hexane-in-water and hexane-in-acetonitrile emulsions were formed, the latter marking the first non-aqueous stabilized-CNT emulsions and corresponding CNT-in-acetonitrile dispersion, further advancing the processability of CNTs. The PIL-stabilized CNT Pickering emulsion droplets generated hollow conductive particles by subsequent drying of the emulsions. With the emulsion templating, the hollow shells can be used as a payload carrier, depending on the solubility of the payload in the droplet phase of the emulsion. This was demonstrated with silicon nanoparticles, which have limited solubility in aqueous environments, but great scientific interest due to their potential electrochemical applications. Overall, this work explored a new class of efficient PIL-ICP hybrid stabilizers with tunable hydrophobicity, offering extended stability of carbon nanotube dispersions with novel applications in hollow particle formation via Pickering emulsion templating and in placing payloads into the shells.
ContributorsHom, Conrad Oliver (Co-author) / Chatterjee, Prithwish (Co-author) / Nofen, Elizabeth (Co-author, Committee member) / Xu, Wenwen (Co-author) / Jiang, Hanqing (Co-author) / Dai, Lenore (Co-author, Thesis director) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2015-12
Description
Carbon Fiber Reinforced Polymers (CFRP) are a promising engineering material because of their multifunctionality and desirable mechanical, electrical, and thermal properties. The mechanical and fracture properties of CFRPs rely on effective stress transfer from the bulk matrix to individual carbon fibers. Pristine carbon fibers (CF) are chemically unreactive and smooth, which inhibits stress transfer mechanisms and makes CF susceptible to matrix debonding. Current composite research aims to improve the synergy between the CF and surrounding matrix by engineering the interphase. The composite interphase is characterized by mechanical properties deviating from the fiber and matrix properties. Carbon nanotubes (CNT), graphene nanoplatelets, and other carbon nanofillers have been studied extensively for their interphase-enhancing capabilities.
ContributorsPensky, Alek R (Author) / Yekani Fard, Masoud (Thesis director) / Zhu, Haolin (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Experimental Characterization of Multifunctional Shape Memory Polymers With Carbon-Based Nanofillers
Description
This paper focuses on the fabrication and characterization of shape memory polymer (SMP) with interspersed carbon-based nanofillers which showed significant improvements in quasi-static and dynamic mechanical properties. These composite shape memory polymers have been fabricated using a specialized acetone solvent mixing technique to achieve high dispersion. The effect of individual and hybrid additions of graphene oxide (GO) and carbon nanotubes (CNT) with a total nanofiller content of 2 wt.% was investigated. These high dispersion SMPs showed significant improvements in tensile moduli (up to 25% over baseline), tensile strength (up to 15% over baseline), and strain to failure (up to 75% over baseline), owing to crack propagation hindrance induced by the carbon nanofillers. Further, dynamic mechanical analysis (DMA) showed a minimal reduction in polymer chain mobility and improvements in storage modulus. Dispersion is characterized by micrograph acquisition and subsequent binary image processing.
ContributorsRoman, Jose (Author, Co-author) / Chattopadhyay, Aditi (Thesis director) / Venkatesan, Karthik (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05