TY - JOUR A1 - Joshi, Ranjit A1 - Friedrich, Jörg Florian A1 - Wagner, M. T1 - Role of hydrogen peroxide in selective OH group functionalization of polypropylene surfaces using underwater capillary discharge N2 - Plasma chemical methods are well suited for introducing functional groups to the surfaces of chemically inert polymers such as polyolefins. However, a broad variety of functional groups are often formed. Unfortunately, for further chemical processing such as grafting of molecules for advanced applications a highly dense monotype functionalized polyolefin surface is needed. Therefore, the main task was to develop a selective surface functionalization process, which formed preferably only a single type of functional groups at the surface in high concentration. Amongst the novel plasma methods, the underwater plasma process (UWP) is one of most attractive options to solve the problem of monotype functionalization. Such plasma is an efficient source of ions, electrons, UV-radiation, high-frequency shock waves, radicals such as hydroxyl radical, and reactive neutral molecules such as hydrogen peroxide. In contrast to established gas phase glow discharge processes, the water phase limits the particle and radiation energies and thus the energy input into the polymer. By virtue of the liquid water environment, which moderates highly energetic plasma species, extensive oxidation, degradation, cross-linking and radical formation on the polymer are more limited as compared to gas plasma exposure. The variety of plasma produced species in the water phase is also much smaller because of the limited reaction possibilities of the plasma with water. The possibility to admix a broad variety of chemical additives makes underwater plasma even more attractive. Hydrogen peroxide and the catalyst (Fe-ZSM5) should influence and increase the equilibrium concentration of OH radicals in the underwater plasma process. It was found that these radicals played a very important role in OH functionalization of polyolefin surfaces. Hydrogen peroxide was identified to be the most prominent precursor for OH group formation in the UWP. The catalyst would affect the steady state of OH radical formation and its reaction with the substrate surface and thus accelerates the functionalization process. KW - Surface modification KW - Polymer functionalization KW - Underwater plasma KW - Capillary discharge KW - Hydroxyl functionalization KW - Hydrogen peroxide KW - Hydroperoxyl radicals KW - Heterogeneous catalysis KW - Fenton-like processes PY - 2011 DO - https://doi.org/10.1163/016942410X520862 SN - 0169-4243 SN - 1568-5616 VL - 25 SP - 283 EP - 305 PB - VNU Science Press CY - Utrecht AN - OPUS4-22413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Quasi-Wasserstoffplasma und Nitrilgruppenentstehung T2 - Plasma Germany CY - Dresden, Germany DA - 2010-05-05 PY - 2010 AN - OPUS4-22734 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Adhäsions-Verbesserung der Haftung zwischen Metallen, Carbonanotubes und Polymeren T2 - Vortrag, Chemieverein Erkner CY - Erkner, Germany DA - 2010-03-17 PY - 2010 AN - OPUS4-22735 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Plasma Polymerization Mechanism T2 - Vortrag im Fachausschuß Plasma und Polymere, Plasma Germany CY - Aachen, Germany DA - 2010-11-15 PY - 2010 AN - OPUS4-22736 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Functionalization of polyolefin surfaces and grafting of molecules with complex architecture T2 - ASPC Leoben CY - Leoben, Austria DA - 2010-09-08 PY - 2010 AN - OPUS4-22737 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Study of Metal-Polymer Interfaces: Relevance to Adhesion T2 - ACS spring meeting CY - Boston, MA, USA DA - 2010-08-21 PY - 2010 AN - OPUS4-22738 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Friedrich, Jörg Florian T1 - Erfahrungsaustaussch: Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen T2 - Vortrag CY - Klingenthal, Germany DA - 2010-03-02 PY - 2010 AN - OPUS4-22739 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Joshi, Ranjit A1 - Schulze, Rolf-Dieter A1 - Meyer-Plath, Asmus A1 - Wagner, M.H. A1 - Friedrich, Jörg Florian T1 - Selective surface modification of polypropylene using underwater plasma technique or underwater capillary discharge N2 - Among new types of plasma processes, the underwater plasma is one of the most attractive methods for functionalization of polymer surfaces. The interesting features of plasma solution system are that the material surfaces to be modified remain in contact with the plasma-moderated solution. The role of plasma-moderated liquids, allows the reach of the reactive species through solution onto the geometrically hindered sites. The UV radiation produced in plasma formation helps in generating additional excited, ionized, and dissociated molecules and species in the reaction solution. An interesting feature of the technique is its flexibility to use a wide variety of additives as or in solution system. This allows us to create a selective or monotype functionalization of material surfaces. Such system was studied for the selective hydroxyl functionalization of polypropylene surface. The oxidation of polymer surfaces and the introduction of O-containing functional groups by underwater plasma was found to exceed concentrations typically achieved in oxygen low-pressure gas discharge plasmas up-to two-folds (maximal 56 O/100 C). The fraction of OH groups among all O-containing moieties amounts from 25 to 40% in comparison to that in the gas plasma of about 10% OH groups. Addition of hydrogen peroxide into this same system increases the fraction of C—O bonds up to 75% (27-OH/100 O). A study was focused to optimize the role of hydrogen peroxide on the efficiency of oxidation and selectivity with chemical derivatization with respect to the formation of mono-sort hydroxyl functionalities, calculated using a chemical derivatization technique. KW - Capillary discharge KW - Functionalization of polymer KW - Modification surfaces KW - Underwater plasma KW - Surface modification KW - Polymer functionalization PY - 2009 DO - https://doi.org/10.1002/ppap.200930601 SN - 1612-8850 SN - 1612-8869 VL - 6 IS - Suppl. 1 SP - 5218 EP - 5222 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Friedrich, Jörg Florian A1 - Wettmarshausen, Sascha A1 - Hennecke, Manfred T1 - Haloform plasma modification of polyolefin surfaces N2 - Polyolefin surfaces (polyethylene and polypropylene) were exposed to haloform (CHX3) plasmas for introduction of monosort halogen groups. Bromoform and chloroform plasmas produced selectively C-Br (100 Br/100 C) and C-Cl (200 Cl/100 C) groups in high yields. The bromoform plasma showed 1-3 and the chloroform plasma 2-7 post-plasma introduced O-functionalities per 100 C. The polyolefin C-Br groups were grafted wet-chemically or by exposure to the vapour of amines, diols and glycols. Thus, spacer molecules could be covalently bonded to maximal 15 spacer molecules per 100 C for the smallest grafted molecules and 1.2 molecules/100 C for larger molecules as octaaminophenylene-POSS. After metal evaporation the end groups of these polymer-bonded spacer molecules formed also covalent bonds to the metal. Thus, flexible, hydrophobic and barrier elements were introduced into the polymer-metal interfaces for high-impact, high-durable and water-resistant metal-polymer composites as measured by means of peel strengths. KW - Bromination KW - Chlorination KW - Selective plasma processes KW - Spacer grafting PY - 2009 DO - https://doi.org/10.1016/j.surfcoat.2009.05.050 SN - 0257-8972 VL - 203 IS - 23 SP - 3647 EP - 3655 PB - Elsevier Science CY - Lausanne AN - OPUS4-23204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Friedrich, Jörg Florian ED - Blasek, G. ED - Bräuer, G. T1 - Modifizieren und Beschichten von Polymeroberflächen KW - Plasma-Oberflächenreinigung PY - 2010 SN - 978-3-87480-257-4 IS - Kap. 2.6 SP - 537 EP - 601 ff. PB - Eugen G. Leuze CY - Bad Saulgau AN - OPUS4-23275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Friedrich, Jörg Florian A1 - Krüger, P. ED - Blasek, G. ED - Bräuer, G. T1 - Feinreinigung von Oberflächen mit Niederdruckplasmen KW - Plasma-Oberflächenreinigung PY - 2010 SN - 978-3-87480-257-4 IS - Kap. 3.15 SP - 1085 EP - 1106 PB - Eugen G. Leuze CY - Bad Saulgau AN - OPUS4-23273 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Friedrich, Jörg Florian ED - Blasek, G. ED - Bräuer, G. T1 - Plasmapolymerisation KW - Plasma-Oberflächenreinigung PY - 2010 SN - 978-3-87480-257-4 IS - Kap. 2.4 SP - 356 EP - 451 PB - Eugen G. Leuze CY - Bad Saulgau AN - OPUS4-23274 LA - deu 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 - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure-property relationship of thin plasma deposited poly(allyl alcohol) films N2 - Poly(allyl alcohol) films with a thickness of about 150 nm were deposited by pulse plasma polymerization onto different substrates (inorganic and organic). The structure/property relationships of these samples were studied in dependence on the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time volume sensitive methods (FTIR and dielectric spectroscopy) are combined with surface analytics by employing XPS for that system. FTIR spectroscopy gives qualitatively the same dependence of the concentration of the OH groups on DC like XPS. The observed differences are discussed considering the different analytical depths of both the methods. The dielectric measurements show that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating. The results obtained by dielectric spectroscopy are discussed in detail with the data from FTIR and XPS measurements. KW - Allyl alcohol KW - Dielectric properties KW - Plasma polymerization KW - Surface and bulk characterization KW - Thermal stability PY - 2011 DO - https://doi.org/10.1007/s11090-011-9297-0 SN - 0272-4324 VL - 31 IS - 3 SP - 477 EP - 498 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-23671 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 - Hanelt, Sven A1 - Orts Gil, Guillermo A1 - Friedrich, Jörg Florian A1 - Meyer-Plath, Asmus T1 - Differentiation and quantification of surface acidities on MWCNTs by indirect potentiometric titration N2 - Wet-chemically oxidized carbon nanotubes (CNTs) generally exhibit both covalently-bound acidic functional groups on the surface and surface-adsorbed acidic substances, i.e. carbonaceous CNT fragments from the oxidation procedure. Direct potentiometric titration of oxidizable high surface area materials with dynamically desorbing acidic fragments is slow and inaccurate. Adsorbed acidic fragments are deprotonated by sodium hydroxide and form anions in solution which is not the case for covalently bound acidic groups on the CNTs, so the following filtration after NaOH treatment separates desorbable acidic substances from non-desorbable or covalently bound groups. For a known concentration of NaOH, titration of the eluate with hydrochloric acid (HCl) allows determination of the concentrations of both types of acidities. However, contrary to reports in the literature, the NaOH consumed by non-desorbed acidic groups has to be accounted for and impedes distinction of desorbed acidic groups via their pKa values. Results are presented of a study on the information content and the reliability of indirect potentiometric Boehm titration for different oxidized multi-walled CNTs. PY - 2011 DO - https://doi.org/10.1016/j.carbon.2011.03.016 SN - 0008-6223 SN - 1873-3891 VL - 49 IS - 9 SP - 2978 EP - 2988 PB - Pergamon Press CY - New York, NY AN - OPUS4-23625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeynalov, Eldar A1 - Friedrich, Jörg Florian T1 - Antioxidative Activity of Carbon Nanotube and Nanofiber N2 - Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) have electron affinities similar to those of fullerenes C60 and C70 and they are therefore capable of acting as radical scavengers in free radical chain reactions, including polymerisation and the thermo-oxidative degradation of polymers. It is assumed that the CNTs and CNFs used as integral part of polymer composites are able to exhibit an antioxidant effect in these materials because of their radical accepting capacity. To examine this presumption the antioxidative activity of original and purified commercial multiwall carbon nanotube MWCNT and carbon nanofibre of platelet structure CNF-PL has been studied by means of a model oxidation reaction of cumene initiated (2,2'-azobisisobutyronitrile, AIBN) in liquid phase. This model reaction was designed to simulate the thermo-oxidative processes in carbon-chain polymers and allows comparison and transfer of obtained results to a polymer system. Kinetic measurements of oxidation rates showed that the effect of inhibition for the model oxidative reaction in the presence of the original and purified MWCNT and CNF-PL strongly depends on the presence of metals (Co, Fe) in the nanoparticles. Rates of oxidation Wo2 (CNT;CNF) observed for the unrefined samples are result of the two competing rates - rate of inhibition Winh.(CNT; CNF) caused by structures of the CNT or CNF and the rates of initiation Wi(M) due to the following interaction: ROOH + M (Co;Fe) i.e, Wo2 ~ W inh (CNT;CNF) + Wi(M). The effective rate constants for the addition of cumyl radicals (R.) to MWCNT and CNF-PL have been determined. These constants reduced to the same concentration (0.5wt.%) and temperature (60°C) units have magnitudes: k1(MWCNT) [MWCNT] = (2.8 ± 0.3) x104 s-1and k1(CNF) [CNF] = (6.0 ± 1.0) x103 s-1. Thus, the effective rate constant, reflecting the antioxidative activity for the CNT, is five times higher than that for the CNF, is about equal to the rate constant for HAS Chimassorb 2020: k1(Chim.2020)[Chim. 2020] = (2.2 ± 0.3) x104 s-1, is ten times less than that for the HAS Chimassorb 119FL: k1(Chim.119FL)[Chim. 119FL] = (2.8 ± 0.3) x105 s-1 and is about forty times less than that for the case of fullerene C60: k1(C60)[C60](353K) = (1.2 ± 0.2) x106 s-1. The kinetic data obtained specify the level of original antioxidative activity of MWCNTs and CNFs and scope of their rational use in polymer composites. It is believed that the results will be helpful for designing optimal profile of polymer composites filled by the CNT/CNFs. KW - Model oxidation KW - Carbon nanotubes KW - Carbon nanofibres KW - Kinetics KW - Oxidation rate KW - Inhibiting activity KW - Rate constant PY - 2008 DO - https://doi.org/10.2174/1874088X00802010028 SN - 1874-088X VL - 2 IS - 1 SP - 28 EP - 34 PB - Bentham Open AN - OPUS4-17839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Joshi, Ranjit A1 - Friedrich, Jörg Florian T1 - Unterwasserplasma zur Funktionalisierung oder Beschichtung von Polymeroberflächen T2 - 16. Neues Dresdner Vakuumtechnisches Kolloquium - Beschichtung, Modifizierung und Charakterisierung von Polymeroberflächen CY - Dresden, Deutschland DA - 2008-10-16 KW - Polymer-Oberflächenfunktionalisierung PY - 2008 SN - 978-3-9812550-0-3 SP - 44 EP - 52 AN - OPUS4-18315 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer-Plath, Asmus A1 - Mach, Reinhard A1 - Maneck, Heinz-Eberhard A1 - Oleszak, Franz A1 - Friedrich, Jörg Florian T1 - Plasma-chemical functionalization of expanded graphite T2 - International Conference on Carbon (Carbon 2008) CY - Nagano, Japan DA - 2008-06-13 KW - Gas Discharge Plasma KW - Expanded Graphite KW - Functionalization KW - Surface Chemistry PY - 2008 SP - 1 EP - 5 AN - OPUS4-18339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeynalov, Eldar A1 - Aliyeva, A. Z. A1 - Friedrich, Jörg Florian T1 - Factors affecting the intrinsic anti-oxidative activity of carbon-nanofibers - Metallic impurities N2 - Nanotubes und Nanofasern (CNT, CNF) besitzen inhärente antioxidative Eigenschaften. Diese Fähigkeit könnte sehr nützlich für die Langzeitstabilität entsprechender Polymercomposite sein. Sie haben Elektronenaffinitäten ähnlich der von Fullerenen und sind deshalb in der Lage, Radikalfallen darzustellen und damit radikalische Kettenreaktionen zu unterbinden. Hier wurde die anti-oxidative Aktivität kommerzieller Nanofasern von Fischgrätenstruktur untersucht. Zunächst wurde der quantitative Einfluss von Ni-Verunreinigungen erfasst. Die eigentliche anti-oxidative Wirkung wurde mit einer aeroben Modelloxidation von Cumol verifiziert und deren kinetischen Parameter für kommerzielle und besonders gereinigte CNF-HBs bestimmt. CNF-HB inhibiert die Modellreaktion durch Einfangen der Peroxiradikale. Die Oxidation vollzieht sich nach einer ausgeprägten Induktionsphase in semi-logarithmischer Abhängigkeit für die speziell gereinigten Spezies. Es konnten erstmals die effektive Konzentration an inhibierenden Zentren und die Inhibierungs-Geschwindigkeitskonstante für CNF-HB bestimmt werden. Die Inhibierungs-Geschwindigkeitskonstante beträgt k7 = (6 ± 1.0) × 103lmol-1 s-1 und liegt damit in der für Anti-Oxidanzien erwarteten Größenordnung. KW - Nanotubes KW - Radical scavenger KW - Anti-oxidative behaviour PY - 2009 SN - 0025-5300 VL - 51 IS - 4 SP - 210 EP - 214 PB - Hanser CY - München AN - OPUS4-19253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -