The Sticky Side of Sugar, Spice, and Everything Nice: Quantifying the Binding of Li+ to Triphenylphosphine Oxide (TPPO) with 7Li and 31P NMR and Volatile and Particulate Emissions from Home 3D Printers
Thach, Colleen Lee
Thach, Colleen Lee
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Abstract
The behavior of lithium cations in nonaqueous solvents influences the performance of lithium-ion batteries; however few measurements have systematically and quantitatively examined the properties of lithium salts in nonaqueous solvents. Results from nuclear magnetic resonance studies designed to interrogate the properties of lithium salt species in the nonaqueous solvents acetonitrile, propylene carbonate, and tetrahydrofuran are presented in the first chapter of this thesis. A suite of lithium-7 and phosphorus-31 spectral data have been collected to study the interactions of lithium cations with a model ligand, triphenylphosphine oxide (TPPO), by titration methods. Our results reveal that the Li-7 chemical shift is dependent on the concentration of added TPPO; however, the equilibria measured for binding of TPPO depend on the nucleus being interrogated, Li-7 or P-31 respectively, a phenomenon attributable to the titration conditions and ratio of reagents used in the titration studies interrogating each element. Ligand binding and solvent effects are discussed, including comparisons between the solution behaviors of various lithium salts. Taken together, current results suggest that both solvent and lithium counteranion identity impact the speciation in nonaqueous solvents. Additionally, the concentrations of lithium and TPPO (as well as the ratio of these concentrations) strongly influence the quantitative data resulting from individual titrations, underscoring the uniqueness of the individual measurements on closely related sets of solution conditions.
The rapid expansion of 3D printing technologies has led to increased utilization in various industries and has also become pervasive in the home environment. Although the benefits are well acknowledged, concerns have arisen regarding potential health and safety hazards associated with emissions of volatile organic compounds (VOCs) and particulates during the 3D printing process. The home environment is particularly hazardous given the lack of health and safety awareness of the typical home user. The study presented in the second chapter of this thesis aims to assess the safety aspects of 3D printing of PLA and ABS filaments by investigating emissions of VOCs and particulates, characterizing their chemical and physical profiles, and evaluating potential health risks. Gas chromatography–mass spectrometry (GC–MS) was employed to profile VOC emissions, while a particle analyzer (WIBS) was used to quantify and characterize particulate emissions. Our research highlights that 3D printing processes release a wide range of VOCs, including straight and branched alkanes, benzenes, and aldehydes. Emission profiles depend on filament type but also, importantly, the brand of filament. The size, shape, and fluorescent characteristics of particle emissions were characterized for PLA-based printing emissions and found to vary depending on the filament employed. This is the first 3D printing study employing WIBS for particulate characterization, and distinct sizes and shape profiles that differ from other ambient WIBS studies were observed. The findings emphasize the importance of implementing safety measures in all 3D printing environments, including the home, such as improved ventilation, thermoplastic material, and brand selection. Additionally, our research highlights the need for further regulatory guidelines to ensure the safe use of 3D printing technologies, particularly in the home setting.
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Date
2025-05-16
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Department of Chemistry, University of Kansas
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Keywords
Battery solvents, Electrolyte, Titrations, Health, Filament