TY - JOUR A1 - Schmid, C. A1 - Falkenhagen, Jana A1 - Beskers, T.F. A1 - Nguyen, L.-T.T. A1 - Wilhelm, M. A1 - Du Prez, F.E. A1 - Barner-Kowollik, C. T1 - Multi-block polyurethanes via RAFT end-group switching and their characterization by advanced hyphenated techniques JF - Macromolecules N2 - The detailed characterization of poly(styrene)-b-poly(tetrahydrofuran) (pS-b-pTHF) multiblock copolymers (17800 g mol-1 ≤ Mn ≤ 46800 g mol-1) generated via urethane linkages is presented. The synthesis of the block copolymers is enabled via a mechanistic switch of the thiocarbonyl thio end group of a poly(styrene) to dihydroxyl terminated polymers that subsequently react with a diisocyanate terminated polytetrahydrofuran based prepolymer to form multiblock copolymer structures. The characterization of the multiblock copolymers and their substructures includes size exclusion chromatography (SEC), liquid chromatography at critical conditions (LCCC), nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy as well as matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. To obtain even further details of the polymer size and its composition, SEC with triple detection as well as newly developed SEC coupled online to IR spectroscopy was carried out. The quantification of the average block fractions via online SEC-IR (41–61 mol % pTHF) is in very good agreement with the results obtained via NMR spectroscopy (39–66 mol % pTHF). PY - 2012 DO - https://doi.org/10.1021/ma301117k SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 16 SP - 6353 EP - 6362 PB - American Chemical Society CY - Washington, DC AN - OPUS4-26942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuntze, Wilhelm A1 - Pfeiffer, F. T1 - Zur Messung des Elastizitätsmoduls von Kunststoffen JF - Wissenschaftliche Abhandlungen der deutschen Materialprüfungsanstalten PY - 1941 SN - 0372-7076 IS - II. Folge/Heft 1 SP - 83 EP - 87 PB - Springer CY - Berlin AN - OPUS4-28396 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuntze, Wilhelm A1 - Pfeiffer, F. T1 - Zur Messung des Elastizitätsmoduls von Kunststoffen JF - Mitteilungen der Deutschen Materialprüfungsanstalten PY - 1942 IS - 30 SP - 608 PB - Springer CY - Berlin AN - OPUS4-17211 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Erning, Johann Wilhelm A1 - Sailer, M. A1 - Pescatore, C. A1 - Boissier, F. A1 - Kessler, J. A1 - Kotra, J. A1 - Löw, S. A1 - Mayor, J.C. A1 - Stroes-Gascoyne, S. A1 - Tokunaga, T. A1 - Compton, K. T1 - The post-closure radiological safety case for a spent fuel repository in Sweden T2 - The post-closure radiological safety case for a spent fuel repository in Sweden KW - Final repository KW - Safety KW - Copper corrosion PY - 2012 SN - 978-92-64-99191-0 VL - 7084 SP - 1 EP - 153 AN - OPUS4-26644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohseninia, A A1 - Eppler, M A1 - Kartouzian, D A1 - Markötter, Henning A1 - Kardjilov, N A1 - Wilhelm, F A1 - Scholta, J A1 - Manke, I T1 - PTFE Content in Catalyst Layers and Microporous Layers: Effect on Performance and Water Distribution in Polymer Electrolyte Membrane Fuel Cells JF - Journal of the Electrochemical Society N2 - This work describes the effects of catalyst layers (CLs) consisting of hydrophobic PTFE on the performance and water management of PEM fuel cells. Catalyst inks with various PTFE contents were coated on Nafion membranes and characterized using contact angle measurements, SEX-EDX, and mercury porosimetry. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were conducted under varying operating conditions for the prepared materials. At dry conditions, CLs with 5 wt.% PTFE were advantageous for cell performance due to improved membrane hydration, whereas under humid conditions and high air flow rates CLs with 10 wt.% PTFE improved the performance in high current density region. Higher PTFE contents (⩾20 wt.%) increased the mass transport resistance due to reduced porosity of the CLs structure. Operando neutron radiography was utilized to study the effects of hydrophobicity gradients within CLs and cathode microporous layer (MPLC) on liquid water distribution. More hydrophobic CLs increased the water content in adjacent layers and improved performance, especially at dry conditions. MPLC with higher PTFE contents increased the overall liquid water within the CLs and GDLs and escalated the water transfer to the anode side. Furthermore, the role of back-diffusion transport mechanism on water distribution was identified for the investigated cells. KW - Neutron imaging KW - Polymer Electrolyte Membrane Fuel Cell KW - Catalyst Layer KW - Microporous Layer KW - Water Distribution PY - 2021 DO - https://doi.org/10.1149/1945-7111/abec53 VL - 168 IS - 3 SP - 034509 PB - IOP Science AN - OPUS4-52402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -