TY - JOUR A1 - Ibrahimov, H.C. A1 - Friedrich, Jörg Florian A1 - Ismailov, E.H. A1 - Zeynalov, Eldar A1 - Aliyeva, A. Z. A1 - Seidov, M.I. A1 - Rustamov, M.I. T1 - Thermal and magnetic peculiarities of metal-containing carbon nano-phase formed in the reaction of fine-dispersed aluminium with dichlorethane in paraffin medium N2 - Electron magnetic resonance (EMR) spectroscopy, X-ray-fluorescent microscopy (XFM) and thermal analysis (TGA/DTA) are used to characterize the carbon nano-phase obtained in the reaction between fine-dispersed aluminium and dichlorethane in the liquid paraffin medium and its modified with Mn(II), Fe(III), Ni(II), Cu(II) chlorides forms were studied. It was shown that the solid nano-structured functionalized carbon systems containing metals possess specific magnetic and thermal properties. Key parameters of the process, influencing on the size and structure of the formed carbon nano-phase were determined. Results and regularities established in this work create presumably the certain basis for optimization of physical and chemical properties of similar systems. KW - Aluminium KW - Dichlorethane KW - Carbon nanostructure KW - Magnetic KW - Thermal properties PY - 2012 SN - 2161-6213 VL - 2 IS - 2 SP - 196 EP - 202 PB - David publishing CY - Libertyville, Illinois, USA AN - OPUS4-25639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited copolymer films prepared from acrylic acid and styrene: Part I dependence on the duty cycle N2 - Copolymers of acrylic acid and styrene (AA/S) were prepared by pulsed plasma deposition and their structures were studied in dependence on the duty cycle (DC) for a fixed composition of 1:1. As a result, low values of DC doses preserve the structure of monomers in the plasma deposited polymers while high DC leads to a higher degree of fragmentation and a loss in regular structure. Regarding plasma copolymerisation as a feasible method to finish surfaces with a definite number of functional groups it is necessary to characterize both, the chemical nature and the physical properties of the deposited layer. Therefore, a combination of different methods was employed for the characterization of thin plasma copolymer films (FTIR, dielectric spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy (XPS)). Special attention was paid on the unambiguous identification of COOH groups at the surface after derivatization with trifluoroethanol by XPS and in the volume by FTIR. The glass transition temperature of the copolymer system is lower than that for the both plasma deposited homopolymers and increases with the DC in difference to plasma deposited poly(acrylic acid). The dielectric measurements showed that the plasma deposited films were not thermally stable and underwent an undesired post-plasma chemical reaction. The results obtained by dielectric spectroscopy are discussed in detail in comparison with the data from FTIR and XPS measurements. KW - Plasmapolymerisation KW - Copolymerisation KW - Acrylic acid–styrene copolymer KW - Dynamic mobility KW - Plasma copolymerisation KW - Surface functionalization KW - Thin film properties PY - 2012 DO - https://doi.org/10.1002/ppap.201100117 SN - 1612-8850 SN - 1612-8869 VL - 9 IS - 3 SP - 273 EP - 284 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Friedrich, Jörg Florian T1 - Degradation behavior of thin polystyrene films on exposure to Ar plasma and its emitted radiation N2 - Spin-coated films of amorphous polystyrene (PS) were exposed to argon plasma for a few seconds to several minutes. The PS film was either in direct contact with the plasma or was shielded from the direct plasma contact by filters with different cutoff wavelengths in the vacuum UV region or by a Faraday cage (FC) made from metal mesh to prevent the impinging of charged species. Only energy-rich neutrals and plasma radiation may be operative in presence of the FC. lithium fluoride (LiF) filter protects the sample from direct contact with the plasma. Wavelengths of plasma radiation shorter than c. 105 nm (≈ 11.8 eV) were cut off. Glass filters made of fused SiO2 have a cutoff at λ ≈175?nm completely the vacuum UV radiation of plasma (ca. 175 nm ≈ 7.0 eV). These energies are sufficient to produce C–C, C–H bond scissions in case of direct Ar plasma exposure and Ar plasma exposure with use of the LiF filter. Only quartz glass shielding did not produce significant effects on the polymer surface in comparison to the reference PS, either in surface energy or O/C ratio or in IR spectra. Oxygen plasma has worked most aggressive and had etched the PS film, thus establishing a steady state between introduction of new oxygen functionalities and polymer etching. Ar plasma exposure produces also oxidation and etching of the polymer films as the oxygen plasma. Using of a FC during Ar plasma exposure or the LiF filter a slightly weaker oxidation was observed. KW - Polystyrene KW - Plasma treatment KW - Plasma emitted radiation KW - Degradation KW - Thin films PY - 2013 DO - https://doi.org/10.1080/01694243.2012.705528 SN - 0169-4243 SN - 1568-5616 VL - 27 IS - 3 SP - 324 EP - 338 PB - VNU Science Press CY - Utrecht AN - OPUS4-26315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited copolymer films prepared from acrylic acid and styrene: Part II variation of the comonomer ratio N2 - Copolymers of acrylic acid and styrene (AA/S) were prepared by pulsed plasma deposition technique. Their structure–property relationships were studied in dependence on the comonomer ratio. Both, the regularity of the structure and the composition of the thin copolymer films were investigated by bulk-sensitive (dielectric spectroscopy, FTIR, and differential scanning calorimetry) as well as surface-sensitive methods such as X-ray photoelectron spectroscopy (XPS). For an unambiguous identification of the functionality of the deposited films the COOH groups were estimated by derivatization with trifluoroethanol and subsequent XPS measurement as well as by the quantitative analysis of the FTIR data. As a result, the concentration of COOH groups on the surface and in the bulk is increasing with the fraction of AA in precursor mixture in a non-monotonous way but similar to the dependence obtained by conventional free radical polymerization. KW - Acrylic acid-styrene copolymer KW - Bulk properties KW - Dielectric properties KW - Plasma polymerization KW - Surface functionalization PY - 2013 DO - https://doi.org/10.1002/ppap.201200110 SN - 1612-8850 SN - 1612-8869 VL - 10 IS - 9 SP - 750 EP - 760 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-29096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Reaction of water with (radicals in) plasma polymerized allyl alcohol (and formation of OH-rich polymer layers) N2 - The pulsed plasma polymerization of allyl alcohol was employed under the aspect of maximal retention of OH groups and the formation of a regular polymer structure. It should be noted that earlier investigations on plasma polymers deposited from allyl alcohol did not show extensive postplasma addition of oxygen and water vapor from ambient air during storage, measuring the elemental O/C ratio by means of X-ray photoelectron spectroscopy (XPS).The identification of OH groups in the plasma polymerized polymer using FTIR spectroscopy was such an indicator for fragmentation. The peak area of OH groups in the film which was stored was increased by about 20% compared to that measured ('in situ'). These phenomenons reflected that moisture and O2 in air played an important role in scavenging the free radicals. The addition of water and more specifically chemical bonding of OH of water in the deposited plasma polymer may serve as an indicator for monomer fragmentation, poly recombination, and the remaining radicals responsible for film formation. Moreover, the dielectric measurements show that the plasma deposited films are not thermally stable but undergo a postplasma chemical reaction during heating, where the reaction kinetics depends on pressure. PY - 2013 DO - https://doi.org/10.1021/jp406186x SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 117 IS - 36 SP - 10603 EP - 10611 PB - Soc. CY - Washington, DC AN - OPUS4-29105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeynalov, Eldar A1 - Friedrich, Jörg Florian A1 - Meyer-Plath, Asmus A1 - Hidde, Gundula A1 - Nuriyev, L. A1 - Aliyeva, A. Z. A1 - Cherepnova, Y. T1 - Plasma-chemically brominated single-walled carbon nanotubes as novel catalysts for oil hydrocarbons aerobic oxidation N2 - Brominated single-walled carbon nanotubes [(Br)n-SWCNT) produced by the plasma-chemical technique were involved in the liquid-phase process of hydrocarbons aerobic oxidation. The significant catalytic effect of the (Br)n-SWCNT was revealed at first by the cumene initiated model oxidation and then in experiments on profound aerobic oxidation of petroleum naphthenic fraction derived from the commercial Azerbaijan (Baku) oils blend diesel cut. The ability of (Br)n-SWCNT to accelerate the aerobic oxidation of the hydrocarbons was found out for the first time. Obviously this phenomenon originates from the peculiarities of electronic configuration of the (Br)n-CNT patterns. The plausible mechanism of (Br)n-SWCNT catalytic action is inclined to the formation of reactive oxygen species. The catalytic activity of (Br)n-SWCNT markedly exceeds the activity of the industrial catalysts, manganese salt of indigenous petroleum acids, used for the liquid phase petroleum hydrocarbons oxidation process. KW - Brominated carbon nanotubes KW - Plasma-chemical technique KW - Model cumene oxidation KW - Oxidation rate KW - Oxidation catalysts KW - Oil hydrocarbons liquid-phase oxidation KW - Manganese naphthenate KW - Synthetic petroleum acids PY - 2013 DO - https://doi.org/10.1016/j.apcata.2013.01.003 SN - 0926-860X SN - 1873-3875 VL - 454 SP - 115 EP - 118 PB - Elsevier CY - Amsterdam AN - OPUS4-28290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohamed, Zeinab A1 - Krüger, Simone A1 - Hidde, Gundula A1 - Schimanski, A. A1 - Jäger, Christian A1 - Friedrich, Jörg Florian T1 - Deposition of thick polymer or inorganic layers with flame-retardant properties by combination of plasma and spray processes N2 - Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 µm plasma thick siloxane-like layers with a thickness of 5 to 40 µm. The adhesion of these bilayer systems and their flame resistance were tested. The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy. Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually. KW - Plasma polymerization KW - Hexamethyldisiloxane plasma polymer KW - Polystyrene KW - Polyethylene KW - Flame retardancy PY - 2013 DO - https://doi.org/10.1016/j.surfcoat.2013.04.039 SN - 0257-8972 VL - 228 SP - 266 EP - 274 PB - Elsevier B.V. CY - Lausanne AN - OPUS4-28735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited poly(acrylic acid) films N2 - Poly(acrylic acid) films with a thickness of about 150?nm were deposited using a pulsed plasma onto aluminum and glass. The structure/property relationships of these samples were studied in dependence to the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time, volume sensitive methods (FTIR, dielectric spectroscopy, and differential scanning calorimetry) are combined with surface analyses i.e. XPS. For an unambiguous identification of COOH groups by XPS, derivatization with trifluoroethanol was accomplished. Quantitative FTIR investigations give qualitatively a dependence of the concentration of COOH groups upon DC similar to that given by XPS investigations. The observed differences are discussed considering the different analytical depths of both methods. The dielectric measurements reveal that the structure of the plasma deposited films is different from that of the bulk material. Moreover, these measurements show also that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating, where the reaction kinetics depends on DC. PY - 2011 DO - https://doi.org/10.1002/ppap.201000108 SN - 1612-8850 SN - 1612-8869 VL - 8 IS - 2 SP - 147 EP - 159 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-23478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mech, A. A1 - Rauscher, H. A1 - Babick, F. A1 - Hodoroaba, Vasile-Dan A1 - Wohlleben, W. A1 - Marvin, H. A1 - Weigel, S. A1 - Brüngel, R. A1 - Friedrich, C. M. T1 - The NanoDefine Methods Manual - Part 1: The NanoDefiner Framework and Tools N2 - The present series of reports, the NanoDefine Methods Manual, has been developed within the NanoDefine project 'Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial', funded by the European Union's 7th Framework Programme, under grant agreement 604347. In 2011 the European Commission (EC) published a recommendation for a definition of the term 'nanomaterial', the EC NM Definition, as a reference to determine whether an unknown material can be considered as a 'nanomaterial' for regulatory purposes1. One challenge is the development of methods that reliably identify, characterize and quantify nanomaterials (NM) both as substances and in various products and matrices. The overall goal of NanoDefine was to support the implementation of the EC NM Definition. It can also support the implementation of any NM definition based on particle size. The project has developed an integrated approach, which allows identifying any material as a nano- or not a nanomaterial according to the EC NM Definition. NanoDefine explicitly supported the governance challenges associated with the implementation of legislation concerning nanomaterials by: - addressing the issues on availability of suitable measuring techniques, reference materials, validated methods, acceptable to all stakeholders (authorities, policy makers, commercial firms), - developing an integrated and interdisciplinary approach and a close international co-operation and networking with academia, commercial firms and standardization bodies. Thus, the NanoDefine Methods Manual provides guidance on practical implementation of the EC NM Definition throughout the nanomaterial characterization process, and on the characterization techniques employed as well as their application range and limits. It assists the user in choosing the most appropriate measurement method(s) to identify any substance or mixture for a specific purpose, according to the EC NM Definition of a nanomaterial. The NanoDefine project also explored how to assess a material against the criteria of the definition through proxy solutions, i.e. by applying measurement techniques that indirectly determine the x50. Those findings were developed through empirically based scientific work and are included in Part 1 of this Manual. As they go beyond the text of the EC NM Definition, they may be used as practical approach to indicate whether a material is a nanomaterial or not, but keeping in mind that they should not be taken as recommendation for the implementation of the EC NM Definition in a regulatory context. The NanoDefine Methods Manual consists of the following three parts:  Part 1: The NanoDefiner Framework and Tools  Part 2: Evaluation of Methods  Part 3: Standard Operating Procedures (SOPs) Part 1 covers the NanoDefiner framework, general information on measurement methods and performance criteria and tools developed by NanoDefine such as a materials categorisation system, a decision support flow scheme and an e-tool. Part 2 discusses the outcome of the evaluation of the nanomaterials characterisation methods for measuring size. Part 3 presents the 23 Standard Operating Procedures developed within the NanoDefine project. The current document is part 1. KW - Nanomaterial KW - Nanoparticles KW - NanoDefine KW - Nanoparticle size distribution KW - Nanomaterial classification KW - Framework KW - Tools PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503699 SN - 978-92-76-11950-0 DO - https://doi.org/10.2760/55181 SN - 1831-9424 SP - 1 EP - 89 PB - Publications Office of the European Union CY - Luxembourg AN - OPUS4-50369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - El Sabbagh, M. A1 - Bedair, M. A1 - Gangan, A. A1 - El-Sabbah, M. A1 - El-Bahy, S. A1 - Friedrich, J. T1 - One-step plasma deposited thin SiOxCy films for corrosion resistance of low carbon steel N2 - Tetraethyl orthosilicate (TEOS) was used as a chemical precursor to deposit ultra-thin SiO x C y plasma polymer films onto mild steel surfaces for preventing the corrosion process. The structure–property relationships of the coatings were evaluated by X-ray Photo Spectroscopy (XPS), X-Ray Diffraction (XRD), Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Energy Dispersive X-ray spectroscopy (EDX) completed with Scanning Electron Microscopy (SEM). The SEM micrographs confirmed a pinhole-free surface morphology of the low-pressure deposited plasma polymer films. The TEOS molecules become fragmented in the plasma by numerous collisions with energy-rich electrons and heavier particles. Recombination of fragments and condensation onto the steel substrate is responsible for the formation of organic SiO containing plasma polymer layers. Such thin layers consist of predominantly SiO x structures. Their properties are determined largely by the gap distance between the two samples used as electrodes in the plasma. The efficiency of the corrosion-protecting coating was compared with uncoated samples. The corrosion protection was determined by exposure of samples to 3.5% NaCl aqueous solutions. For this purpose, polarization and Electrochemical Impedance Spectroscopy (EIS) were used to monitor the corrosion. The optimal gap distance between the electrodes was determined for corrosion protection. The best protective efficiency reached more than 97% of the total protection as measured at room temperature. KW - Thin films KW - Corrosion resistance KW - Mild steel KW - Plasma treatments KW - Tetraethyl orthosilicate PY - 2020 DO - https://doi.org/10.1080/01694243.2020.1856539 VL - 35 IS - 16 SP - 1734 EP - 1751 PB - Taylor & Francis AN - OPUS4-52303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hirschberg, L. A1 - Bake, Friedrich A1 - Knobloch, K. A1 - Hulshoff, S. A1 - Hirschberg, A. T1 - Experimental investigations of indirect noise due to modulation of axial vorticity and entropy upstream of a choked nozzle N2 - An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in the main flow. This eventually induces a large downstream acoustic pulse when tangential injection is interrupted. The magnitude of the resulting sound pulse can reach that of a quasi-steady response of the nozzle to a large air patch with a uniform stagnation temperature equal to that of the upstream-injected heated air. This hypothesis is consistent with the fact that the initial indirect-sound pulse is identical to one obtained with unheated air injection. The authors posit that – given all of the insight gleaned from them in this case – acoustic measurements of indirect sound appear to be a potentially useful diagnostic tool. KW - Aeroacoustics KW - Indirect combustion noise KW - Vorticity noise KW - Entropy noise KW - Swirl PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548331 DO - https://doi.org/10.1016/j.jsv.2022.116989 SN - 0022-460X VL - 532 SP - 1 EP - 22 PB - Elsevier Ltd. AN - OPUS4-54833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeynalov, Eldar A1 - Maherramova, S.N. A1 - Sadieva, N.F. A1 - Iskenderova, S.A. A1 - Agayev, B. K. A1 - Friedrich, Jörg Florian T1 - New softeners for polyvinylchloride N2 - Die Produktion von neuen effektiven und 'grünen' Weichmachern für Polyvinylchlorid (PVC) stellt eine der großen Herausforderungen in der chemischen Industrie dar. In diesem Beitrag wird über Ergebnisse von Untersuchungen berichtet, in denen symmetrische Ester einer Reihe von Fettsäuren und Triethylenglykol (TEG) gewonnen wurden und die als effektive Plastifizierungskomponenten verwendet wurden. Die Veresterung wurde unter Zugabe von Titandioxid Degussa P-25 in Nanopartikelgröße als umweltverträgliche Technologie durchgeführt. Eine gute Verträglichkeit und eine niedrige Flüchtigkeit der Ester auf Biobasis in den PVC-Rezepturen werden gezeigt und es konnten bessere physiko-mechanische Eigenschaften der PVC-Komposite eingestellt werden. Die Ester können als effektive und umweltfreundliche PVC-Weichmacher und als Ersatz für herkömmliche Phtalate empfohlen werden. KW - Softener KW - Polyvinylchloride PY - 2012 SN - 0025-5300 VL - 54 IS - 4 SP - 246 EP - 248 PB - Hanser CY - München AN - OPUS4-25747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -