Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 12 of 12 for “"partially fluorinated"”.
-
Partially-Fluorinated Polyimides using Aliphatic Diamines
… of titanium dioxide nanoparticles. Two series of partially-fhiorinated polyimides made using aliphatic diamines as the flexible component and titaniumdioxide nanoparticles were synthesized. All of the reactions were performed via condensation polymerization. Thermal data suggest that the obtained …
-
Proton Exchange Membrane Fuel Cell Systems Based on Aromatic Hydrocarbon and Partially Fluorinated Disulfonated Poly(Arylene Ether) Copolymers
… bonded electrodes more compatible with the partially fluorinated copolymer membranes. The influence of surface enrichment had two important roles in increasing both initial and long term performance tests. The surface fluorine provided lower contact resistance and lower water uptake. The …
-
Synthesis and Characterization of Hydrophobic-Hydrophilic Multiblock Copolymers for Proton Exchange Membrane Applications
… PEM materials are typically based on perfluorinated sulfonic acid containing ionomers (PFSAs), represented by DuPont's Nafion®. Despite their good chemical stability and proton conductivity at high relative humidity (RH) and low temperature, several major drawbacks have been observed on …
-
Instrumentation, Applications And Fundamentals Of Plasma Ionization Of Organic Molecules From Surfaces
… chains as a function of the counter anion, and a partially fluorinated polymer was broken down into tetrafluoroethylene monomers which immediately polymerized to form perfluorinated alkyl chains.</p>
-
Characterization of Structure-Property Relationships in Hydrophilic-Hydrophobic Multiblock Copolymers for Use in Proton Exchange Membrane Fuel Cells
… including good proton conductivity under partially humidified conditions. A number of alternative PEMs have been synthesized by copolymerizing various aromatic comonomers, but the smaller ion channels prohibit rapid proton transport under partially hydrated conditions. One solution has …
-
Elucidating the Role of Fluorine on Gas Transport Through Fluorinated Polymer Membranes
Fully fluorinated polymers (i.e., perfluoropolymers) are a unique class of materials that have shown exceptional separation performance due to their anomalous thermodynamic partitioning compared to typical hydrocarbon polymers. The goal of this work is to elucidate the role of fluorine on gas …
-
Thermal Decomposition Mechanisms of Per- and Polyfluoroalkyl Substances and Application to Analysis of Total Organofluorine
… broadly defined as containing a fully or partially fluorinated alkyl chain. PFASs are ubiquitous in the environment due to their wide application in consumer products and aqueous film-forming foams (AFFFs) for over 70 years. The likelihood of exposure in combination with the potential for …
-
Fluorocarbene, Fluoroalkyl, and Fluoride Complexes of First-Row Transition Metals
Fluorinated organic compounds play important roles in our society, as these products range from life-saving pharmaceuticals and agrochemicals, to fluoropolymers with extremely high thermal and chemical stability. Although elemental fluorine (F2) is the most reactive element, some fluoro-organic …
-
Evaluation of process parameters and membranes for SO2 electrolysis
… excess polymer which was blended with either partially fluorinated aromatic polyether (sFS001), poly(2,6-dimethylbromide-1,4-phenylene oxide (PPOBr) or poly(tetrafluorostyrene-4-phosphonic acid) (PWN) in various ratios. Some of the blend membranes also contained a cross-linking agent which was …
-
High Performance Disulfonated Poly(arylene Sulfone) Co- and Terpolymers For Proton Exchange Membranes For Fuel Cell And Transducer Applications: Synthesis, Characterization And Fabrication Of Ion Conducting Membranes
… terpolymer. This suggested that the hydrophobic fluorinated material aided in water repulsion of the system. Proton conductivity decreased slightly as the amount of fluorination increased, which was interpreted to be due to the decrease in the ion-exchange capacity. High temperature hydrogen/air …
-
A Morphological Study of PFCB-Ionomer/ PVdF Copolymer Blend Membranes For Fuel Cell Application
A new material for use as a proton exchange membrane in fuel cells has been developed: a blend of a perfluorocyclobutane-based block ionomer (S-PFCB) and Poly (vinylidene-co-hexafluoropropylene) (Kynar Flex, KF). This thesis details the work done thus far to characterize the morphology of this …
-
Removal of Perfluorooctane Sulfonate (PFOS) and Related Compounds From Industrial Effluents
… toxicity, and bioaccumulation. These perfluorinated compounds have been used for more than half a century in a wide variety of industrial and consumer products ranging from stain repellents such as Teflon® to aqueous fire-fighting foams and to grease-proof food packing. The public health …