Browsing by Subject "Biopolymer"
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Item Biopolymer Composites with Dairy Protein for Use in Additive Manufacturing(2022) Delwiche, Maia; Obielodan, JohnAs the popularity and versatility of additive manufacturing grows, so does interest in developing new materials, including biopolymers. Casein is a protein found in dairy and historically, has been used in food applications, but its use as a biomaterial for engineering structures is less common. This study investigates the development of composite materials for additive manufacturing with casein as a biomaterial filler. To observe the effects of casein on material properties, vat photopolymerization-based and fused filament fabrication-based matrix materials were combined with different weight fractions of casein. Test samples were fabricated to evaluate tensile properties. Test results show a maximum increase of 4% for FFF and 34% for SLA in the stiffness of the materials with casein compared to the neat matrix materials. However, the composite materials showed between 12% and 54% reductions in ductility, and marginal decreases in tensile strengths. The preliminary results indicate viability and prompt further investigation into casein-polymer composites for additive manufacturing.Item The development and evaluation of polymers for enhanced oil recovery(2015-08) Lee, Vincent Bing; Pope, G. A.; Weerasooriya, Upali PThe main purpose of this research was to develop, test and evaluate polymers for enhanced oil recovery. Commercially available hydrolyzed polymacrylamide polymers were characterized in filtration tests and corefloods. Scleroglucan biopolymers were studied and developed as an alternative to synthetic polymers for enhanced oil recovery Strategies for preparing filterable solutions of scleroglucan were tested on Cargill CS-11 scleroglucan. As a result, an improved method was developed and the transport behavior of the filterable solution was characterized in corefloods without the presence of oil. Experiments showed that although the improved pH-treatment method produced solutions with excellent filtration ratios, the solution did not transport well through Bentheimer cores. A new prototype EOR-grade liquid scleroglucan sample, AD-10, was provided by Cargill. Filtration results were good and the AD-10 showed excellent viscosifying power in harsh conditions of high salinity, high hardness, and elevated temperature. Solutions of the AD-10 were tested in coreflood without oil through Bentheimer and Berea sandstones at room temperature and one coreflood at 100 °C. Polymer retention was lower at higher temperature for cores of similar permeability. Shear correction factors of 1.3-1.6 were determined for AD-10 scleroglucan solutions through sandstone at 25 °C. BASF Aspiro™ hydrolyzed polyacrylamide polymers, 4211x, 4261x, 4231, 4251, were tested for filterability. The higher the molecular weight of the HPAM polymer, the less consistently the polymer could be prepared to pass filtration tests. The Aspiro 4211x and 4261x polymers were tested in subsequent corefloods without the presence of oil through Bentheimer sandstones. Shear correction factors of 2.1 were determined for solutions of Aspiro 4211x and 4261x through Bentheimer sandstones at 25 °C. Polymer flood oil recovery experiments were performed with Hengju Hengfloc 63026 hydrolyzed polyacrylamide (HPAM) through reservoir sandpacks, as part of a blind study with other HPAM polymers.Item Development of quantitative three-dimensional thermal noise imaging of biopolymer filaments(2012-05) Kochanczyk, Martin David; Florin, Ernst-Ludwig; Shubeita, George; Marder, Michael; Bengtson, Roger; Zhang, John XBiopolymer networks perform many essential functions for living cells. Most of these networks show a highly nonlinear mechanical response that is well-studied on the macroscopic scale. While much work has been done to connect the macroscopic responses of networks to microscopic parameters, such as filament stiffness, cross-linking geometry and pore size, there is a lack of experimental techniques that can measure these properties in situ. This thesis presents the development of a quantitative scanning probe imaging technique, which can explore soft matter in an aqueous environment. An optical tweezer-based microscope, called a photonic force microscope, was designed and constructed. A stability analysis method, called Power Spectrum Integration Analysis, was developed and was used to show that the photonic force microscope achieves nanometer precision in the measurement of probe position with a bandwidth of 1MHz. A novel single filament assay was developed that allowed for the isolation and probing of individual biopolymer filaments. A scanning probe technique, called thermal noise imaging, which uses the diffusive motion of an optically trapped nanoparticle as a fast, natural scanner, was used to scan microtubules grafted on one end. The resulting thermal noise images were strongly influenced by the thermally driven, transverse fluctuations of the filaments. Analytical tools, which include Brownian dynamics simulations of probe and filament, were developed to assist quantitative analysis of thermal noise images. The persistence length of individual microtubules was extracted, and the length dependence persistence length for taxol stabilized microtubules was confirmed. The transverse fluctuations of a microtubule grafted on both ends were imaged. Finally, thermal noise images of collagen filaments inside a three-dimensional collagen network were recorded, and variations of the filament diameter were extracted. This thesis establishes thermal noise imaging as a quantitative tool for studying soft material on the nanometer scale, as well as paves the way for investigating force distributions inside biopolymer networks.Item Imaging microtubule shape fluctuations and networks for studying cytoskeleton network structure and mechanics(2019-11-14) Himmelsbach, Michael S; Florin, Ernst-Ludwig; Alvarado, José; Baker, Aaron; Fink, Manfred; Gordon, VernitaA large part of the mechanical integrity and biological functionality of eukaryotic cells relies on a network of filaments called the cytoskeleton. The overall mechanical properties of the cytoskeleton have their origin in the properties of individual filaments and the network architecture. Microtubules are the stiffest type of cytoskeletal filament with a persistence length in the millimeter range. These semiflexible filaments form networks where bending elasticity contributes to the force distribution and the overall mechanical properties. Long-standing efforts to model individual cytoskeletal components have resulted in a number of predictions that are not testable by video microscopy with a camera, and the mechanics of individual microtubules are not well understood. As a result, interpreting emergent mechanical properties of microtubule networks remains difficult. Here we introduce two novel methods which addresses the need to study structural and mechanical properties of single filaments and networks. The first method allows high bandwidth tracking of microtubule shape fluctuations using light scattered by the filament to study dynamics of individual microtubules. By assessing the light scattered by single and multiple filaments, the possibility for in situ characterization the molecular scale architecture is demonstrated. The power spectral density of thermally fluctuating microtubules can be measured with high precision over a wide range of frequencies (1–104 Hz). The filament dynamics are interpreted in terms of the wormlike chain model for semiflexible filaments. The second method, thermal noise imaging, is a three-dimensional scanning probe technique that utilizes the confined thermal motion of a 200 nm optically trapped particle as a noninvasive probe. We achieved 10 nm precision in localizing the filament axes. The presence of filaments leads to excluded volumes in the region scanned by the probe. Quantitative information about crosslinking geometry and filament curvature can be extracted from the data. Transverse filament fluctuations lead to a reduction in the excluded volume. Since such fluctuations depend on filament stiffness, network architecture and the force transmitted through each filament, thermal noise imaging provides a novel way to study biopolymer network structure and force distribution label-free with nanometer scale resolution in three dimensions.