TY - JOUR A1 - Friedrich, Jörg Florian A1 - Hidde, Gundula A1 - Lippitz, Andreas A1 - Unger, Wolfgang T1 - Plasma bromination of graphene for covalent bonding of organic molecules N2 - Plasma-chemical bromination applied to graphitic materials, in particular to highly ordered pyrolytic graphite is reviewed. The resulting bromination efficiency of the plasma-chemical treatment was subject of systematic process optimization. The plasma of elemental bromine vapour produced bromine concentrations on graphene surfaces of more than 30 % Br/C using either inductively or capacitively coupled low-pressure radio-frequency plasmas. Plasma brominated graphite surfaces have been studied by Near Edge X-ray Absorption Fine Structure, X-ray Photoelectron Spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy. The introduction of bromine into graphene-like graphite layers and its binding situation were investigated. To study the physical effect of the plasma bromination process, Kr plasma was also used because of its chemical inertness but similar atomic mass. Covering the samples with a Faraday cage or with a LiF window should help to differentiate between physical, chemical and radiation effects of the plasma. Bromination was assigned to radical or electrophilic addition of bromine onto fully substituted aromatic double bonds (sp² C) with exothermal reaction enthalpy. Low bromination shows a strong decay of aromatic double bonds, higher bromination percentage let disappear all aromatic rings. The formed C–Br bonds were well suited for efficient grafting of organic molecules by post-plasma wet-chemical nucleophilic substitution. This grafting onto the graphene surface was demonstrated using aminosilane and different diamines. The bromination of double bonds changes the hybridization of carbon atoms from plane sp² to tetrahedral sp³ hybridization. Thus, the plane topography of graphene is destroyed and the conductivity is lost. KW - Graphene KW - Bromination KW - Grafting of diamines KW - Plasma KW - Organic graphting PY - 2014 DO - https://doi.org/10.1007/s11090-013-9509-x SN - 0272-4324 VL - 34 SP - 621 EP - 645 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-30575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wettmarshausen, Sascha A1 - Min, Hyegeun A1 - Unger, Wolfgang A1 - Jäger, Christian A1 - Hidde, Gundula A1 - Friedrich, Jörg Florian T1 - Significance of hydrogen-deuterium exchange at polyolefin surfaces on exposure to ammonia low-pressure plasma N2 - Since more than 40 years ammonia plasma exposure of polyolefins is used for introduction of primary amino groups. The selectivity of this reaction and the yield in primary amino groups was found to be low. Here, a prominent side-reactions of this process was investigated, the hydrogenation by NH3 plasma. For identification of hydrogenation ammonia (NH3) and deuterated ammonia (ND3) were exposed to Polyethylene (h-PE) and fully deuterated polyethylene (d-PE) as well as hexatriacontane (h-HTC) and fully deuterated hexatriacontane (d-HTC) as low-molecular weight model for PE. H–D exchange was assumed and detected by Time-of-Flight Secondary Ion Mass Spectrometry (ToF–SIMS), X-ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance (ATR-FTIR) and 1H and 2H Nuclear magnetic Resonance. Results show a significant H–D exchange within the sampling depth of ATR (2.5 µm). However, N- and NH2 introduction was limited to the topmost surface as shown by SIMS and XPS (a few nanometers). KW - Deuterated ammonia KW - Ammonia plasma KW - Deuterated polyolefins KW - Hexatriacontane KW - H-D exchange PY - 2011 DO - https://doi.org/10.1007/s11090-011-9304-5 SN - 0272-4324 VL - 31 IS - 4 SP - 551 EP - 572 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-24178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Min, Hyegeun A1 - Wettmarshausen, Sascha A1 - Friedrich, Jörg Florian A1 - Unger, Wolfgang T1 - A ToF-SIMS study of the deuterium-hydrogen exchange induced by ammonia plasma treatment of polyolefins N2 - ToF-SIMS has been used to study the surface functionalization of polypropylene and polyethylene samples by exposure to low-pressure ammonia plasma. Static secondary ion mass spectrometry is an appropriate tool to determine hydrogen isotopes as elements and in fragment ions with high sensitivity and selectivity. Specifically the exchange of hydrogen isotopes and the incorporation of N-containing moieties in the near-surface layer of the polyolefins have been studied in ND3 plasma experiments with conventional polypropylene (h-PP) and polyethylene (h-PE) and NH3 plasma experiments with deuterated polyethylene (d-PE). Considering the exchange of hydrogen between the plasma and the polymer surface studied by using deuterated ammonia and polyolefin samples the conclusion has been derived that polypropylene with its side chain methyl groups is more susceptible to hydrogen exchange reactions. For ND3 plasma treatment of polyethylene and polypropylene similar N-containing fragments were obtained and the measured semi-quantitative ToF-SIMS N-uptake data are rather similar. The observation of a wide range of characteristic mixed CkNlHmDn+ secondary fragment ions suggests complex and manifold reaction pathways at the polymer–plasma interface besides simple grafting of –ND2 or –NH2 moieties formed by ammonia fragmentation in the plasma. Finally, indications of an isotopic effect for hydrogen isotopes in the plasma process have been observed by comparison of ND3/h-PE results with those of NH3/d-PE. KW - ToF-SIMS KW - Hydrogen-deuterium exchange KW - Ammonia plasma treatment KW - Amine-functionalized polymer KW - Polyolefins PY - 2011 DO - https://doi.org/10.1039/c1ja10043b SN - 0267-9477 SN - 1364-5544 VL - 26 SP - 1157 EP - 1165 PB - Royal Society of Chemistry CY - London AN - OPUS4-23754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kannengießer, Thomas A1 - Florian, Wolfgang A1 - Wilken, Klaus T1 - Moderne Möglichkeiten der Prüfung und Simulation von Bauteilschweißungen N2 - Die hier vorgestellte Großanlage zur Prüfung und Simulation von Bauteil­ schweißungen (GAPSI 16) mit einer Maximalprüfkraft von ±16 MN erlaubt wirklichkeitsnahe Analysen des Bau­ teilverhaltens während des Schwei­ ßens. Ein fundamentaler Vorteil ge­ genüber konventionellen Universal­ prüfmaschinen ist, Momente während des Schweißens mittels acht unabhän­ giger Hydraulikzylinder in zwei Prüf­ tischen aufbringen bzw. registrieren zu können. Derzeitige Forschungsvorhaben sind zum einen Spannungs- und Verformungsvorgängen während des Schweißens von Blechen und zum anderen Modellen gewidmet, womit Kenngrößen für Flammrichtarbeiten ermittelt werden können. Simulations­ versuche an Großproben tragen we­ sentlich zu höherer Aussagesicherheit bei, zumal konventionelle Prüfmetho­ den mit einfachen Kleinproben und auch Berechnungen nach der Finite­ Elemente-Methode (FEM) stets Rand­ bedingungen und zumeist größere Idealisierungen enthalten. Dagegen weist die Großprüfanlage GAPSI 16 mit angepaßten Probengeometrien und Spannkräften einen neuen Weg. KW - GAPSI 16 KW - Prüfung und Simulation KW - Bauteilschweißungen PY - 1997 SN - 0943-4569 VL - 70 IS - 5 SP - 192 EP - 194 PB - Allianz Versicherungen AG CY - München AN - OPUS4-38257 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Amon, H. A1 - Florian, Wolfgang T1 - Härtemessungen in der Wärmeeinflusszone von Schweissverbindungen T2 - Tagung Werkstoffprüfung CY - Bad Nauheim, Germany DA - 1984-12-06 PY - 1985 SP - 115 EP - 131 PB - DVM CY - Berlin AN - OPUS4-34254 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Wolfgang T1 - Stand der Normung, Forschungs- und Entwicklungsaktivitäten im Bereich der Kaltrißbildung PY - 1985 SP - 1 EP - 15 PB - SLV-Duisburg CY - Duisburg AN - OPUS4-34257 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Florian, Wolfgang A1 - Jafari, S. T1 - Meßtechnische Erfassung von Bondparametern PY - 1985 SN - 0172-6250 SN - 0943-0962 SP - 365 EP - 367 PB - Konradin-Verl. CY - Leinfelden-Echterdingen AN - OPUS4-34258 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Wolfgang A1 - Jaenicke, Bernd T1 - Entwicklung von Konstruktions- und Fertigungsrichtlinien zur optimalen Gestaltung und Herstellung geschweißter, einsatzgehärteter Großzahnräder T2 - Informationstagung des Wissenschaftlichen Beirats der Forschungsvereinigung Antriebstechnik CY - Bad Soden, Germany DA - 1985-11-12 PY - 1985 SP - 1 EP - 18 PB - Forschungsvereinigung Antriebstechnik CY - Frankfurt am Main AN - OPUS4-34259 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Preß, Henning A1 - Florian, Wolfgang T1 - Formation of toxic substances in gas shielded arc welding PY - 1985 SN - 0043-2288 SN - 1878-6669 VL - 23 IS - 1/2 SP - 4 EP - 12 PB - Springer CY - Oxford AN - OPUS4-34270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Preß, Henning A1 - Florian, Wolfgang T1 - Untersuchung der Fremdstoffbildung beim Schutzgasschweißen - Metall-Inertgas- und Metall-Aktivgasschweißen von Aluminium und Stahl PY - 1983 SN - 0036-7184 VL - 35 IS - 5 SP - 211 EP - 216 PB - DVS-Media GmbH CY - Düsseldorf AN - OPUS4-40723 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -