1
|
Ucpinar Durmaz B, Aytac A. Enhanced mechanical and thermal properties of graphene nanoplatelets‐reinforced polyamide11/poly(lactic acid) nanocomposites. POLYM ENG SCI 2022. [DOI: 10.1002/pen.26189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bedriye Ucpinar Durmaz
- Faculty of Engineering, Department of Chemical Engineering Kocaeli University Kocaeli Türkiye
| | - Ayse Aytac
- Faculty of Engineering, Department of Chemical Engineering Kocaeli University Kocaeli Türkiye
- Polymer Science and Technology Programme Kocaeli University Kocaeli Türkiye
| |
Collapse
|
2
|
Eshraghian A, Kamkar M, Sundararaj U. Asphaltene/Polymer Composites: Morphology, Compatibility, and Rheological Properties. CAN J CHEM ENG 2022. [DOI: 10.1002/cjce.24564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Afrooz Eshraghian
- Department of Chemical & Petroleum Engineering University of Calgary Calgary AB Canada
| | - Milad Kamkar
- Department of Chemical & Petroleum Engineering University of Calgary Calgary AB Canada
| | | |
Collapse
|
3
|
Fabrication of PLA/PCL/Graphene Nanoplatelet (GNP) Electrically Conductive Circuit Using the Fused Filament Fabrication (FFF) 3D Printing Technique. MATERIALS 2022; 15:ma15030762. [PMID: 35160709 PMCID: PMC8836401 DOI: 10.3390/ma15030762] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/07/2022] [Accepted: 01/17/2022] [Indexed: 02/01/2023]
Abstract
For the purpose of fabricating electrically conductive composites via the fused filament fabrication (FFF) technique whose properties were compared with injection-moulded properties, poly(lactic acid) (PLA) and polycaprolactone (PCL) were mixed with different contents of graphene nanoplatelets (GNP). The wettability, morphological, rheological, thermal, mechanical, and electrical properties of the 3D-printed samples were investigated. The microstructural images showed the selective localization of the GNPs in the PCL nodules that are dispersed in the PLA phase. The electrical resistivity results using the four-probes method revealed that the injection-moulded samples are insulators, whereas the 3D-printed samples featuring the same graphene content are semiconductors. Varying the printing raster angles also exerted an influence on the electrical conductivity results. The electrical percolation threshold was found to be lower than 15 wt.%, whereas the rheological percolation threshold was found to be lower than 10 wt.%. Furthermore, the 20 wt.% and 25 wt.% GNP composites were able to connect an electrical circuit. An increase in the Young’s modulus was shown with the percentage of graphene. As a result, this work exhibited the potential of the FFF technique to fabricate biodegradable electrically conductive PLA-PCL-GNP composites that can be applicable in the electronic domain.
Collapse
|
4
|
Mitkus R, Scharnofske M, Sinapius M. Characterization 0.1 wt.% Nanomaterial/Photopolymer Composites with Poor Nanomaterial Dispersion: Viscosity, Cure Depth and Dielectric Properties. Polymers (Basel) 2021; 13:3948. [PMID: 34833246 PMCID: PMC8618496 DOI: 10.3390/polym13223948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
Notably, 3D printing techniques such as digital light processing (DLP) have the potential for the cost-effective and flexible production of polymer-based piezoelectric composites. To improve their properties, conductive nanomaterials can be added to the photopolymer to increase their dielectric properties. In this study, the microstructure, viscosity, cure depth, and dielectric properties of ultraviolet (UV) light curable 0.1 wt.% nanomaterial/photopolymer composites are investigated. The composites with multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and carbon black (CB) are pre-dispersed in different solvents (acetone, isopropyl alcohol, and ethanol) before adding photopolymer and continuing dispersion. For all prepared suspensions, a reduction in viscosity is observed, which is favorable for 3D printing. In contrast, the addition of 0.1 wt.% nanomaterials, even with poor dispersion, leads to curing depth reduction up to 90% compared to pristine photopolymer, where the nanomaterial dispersion is identified as a contributing factor. The formulation of MWCNTs dispersed in ethanol is found to be the most promising for increasing the dielectric properties. The post-curing of all composites leads to charge immobility, resulting in decreased relative permittivity.
Collapse
Affiliation(s)
- Rytis Mitkus
- Technische Universität Braunschweig, Institute of Mechanics and Adaptronics, Langer Kamp 6, 38106 Braunschweig, Germany; (M.S.); (M.S.)
| | | | | |
Collapse
|
5
|
Zakizadeh M, Arefazar A, Javadzadeh M. Investigation on the effect of GMA-graft structure in SAN-g-GMA-coSt on inter-phase behavior, thermal stability, and mechanical properties of PC/SAN/GO nanocomposites. Polym Bull (Berl) 2021. [DOI: 10.1007/s00289-020-03420-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
6
|
Thermal/Electrical Properties and Texture of Carbon Black PC Polymer Composites near the Electrical Percolation Threshold. JOURNAL OF COMPOSITES SCIENCE 2021. [DOI: 10.3390/jcs5080212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Polycarbonate (PC), a thermoplastic polymer with excellent properties, is used in many advanced technological applications. When PC is blended with other polymers or additives, new properties, such as electrical properties, can be available. In this study, carbon black (CB) was melt-compounded with PC to produce polymer compounds with compositions (10–16 wt.% of CB), which are close to or above the electrical percolation threshold (13.5–14 wt.% of CB). Effects due to nanofiller dispersion/aggregation in the polymer matrix, together with phase composition, glass transition temperature, morphology and textural properties, were studied by using thermal analysis methods (thermogravimetry and differential scanning calorimetry) and scanning electron microscopy. The DC electrical properties of these materials were also investigated by means of electrical conductivity measurements and correlated with the “structure” of the CB, to better explain the behaviour of the composites close to the percolation threshold.
Collapse
|
7
|
Dispersion of graphite nanoplates in melt mixed PC/SAN polymer blends and its influence on rheological and electrical properties. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122577] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
8
|
Boldt R, Leuteritz A, Schob D, Ziegenhorn M, Wagenknecht U. Barrier Properties of GnP-PA-Extruded Films. Polymers (Basel) 2020; 12:polym12030669. [PMID: 32192140 PMCID: PMC7183322 DOI: 10.3390/polym12030669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/03/2020] [Accepted: 03/06/2020] [Indexed: 11/16/2022] Open
Abstract
It is generally known that significant improvements in the properties of nanocomposites can be achieved with graphene types currently commercially available. However, so far this is only possible on a laboratory scale. Thus, the aim of this study was to transfer results from laboratory scale experiments to industrial processes. Therefore, nanocomposites based on polyamide (PA) and graphene nanoplatelets (GnP) were prepared in order to produce membranes with improved gas barrier properties, which are characterized by reduced permeation rates of helium. First, nanocomposites were prepared with different amounts of commercial availably graphene nanoplatelets using a semi-industrial-scale compounder. Subsequently, films were produced by compression molding at different temperatures, as well as by flat film extrusion. The extruded films were annealed at different temperatures and durations. In order to investigate the effect of thermal treatment on barrier properties in correlation to thermal, structural, and morphological properties, the films were characterized by differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), optical microscopy (OM), transmission electron microscopy (TEM), melt rheology measurements, and permeation measurements. In addition to structural characterization, mechanical properties were investigated. The results demonstrate that the permeation rate is strongly influenced by the processing conditions and the filler content. If the filler content is increased, the permeation rate is reduced. The annealing process can further enhance this effect.
Collapse
Affiliation(s)
- Regine Boldt
- Leibniz Institute of Polymer Research Dresden (IPF), Hohe Strasse 6, 01069 Dresden, Germany; (A.L.); (U.W.)
- Correspondence:
| | - Andreas Leuteritz
- Leibniz Institute of Polymer Research Dresden (IPF), Hohe Strasse 6, 01069 Dresden, Germany; (A.L.); (U.W.)
| | - Daniela Schob
- Faculty Mechanical Engineering, Electrical and Energy Systems, Institute of Mechanical Engineering and Management, Brandenburg University of Technology Cottbus-Senftenberg, Universitaetsplatz 1, 01968 Senftenberg, Germany; (D.S.); (M.Z.)
| | - Matthias Ziegenhorn
- Faculty Mechanical Engineering, Electrical and Energy Systems, Institute of Mechanical Engineering and Management, Brandenburg University of Technology Cottbus-Senftenberg, Universitaetsplatz 1, 01968 Senftenberg, Germany; (D.S.); (M.Z.)
| | - Udo Wagenknecht
- Leibniz Institute of Polymer Research Dresden (IPF), Hohe Strasse 6, 01069 Dresden, Germany; (A.L.); (U.W.)
| |
Collapse
|
9
|
Chirila C, Botea M, Iuga A, Tomulescu AG, Balescu L, Galca AC, Boni AG, Leonat L, Pintilie I, Pintilie L. Carbon-based sprayed electrodes for pyroelectric applications. PLoS One 2019; 14:e0221108. [PMID: 31415643 PMCID: PMC6695221 DOI: 10.1371/journal.pone.0221108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/30/2019] [Indexed: 11/19/2022] Open
Abstract
A carbon-based layer was deposited by spraying on top of a ferroelectric layer grown by sol-gel on Si (001) substrate and its properties as electrode and absorber for pyroelectric detection were tested. It was found that the electric properties of the ferroelectric capacitor with top carbon-based sprayed electrode (CBSE) are comparable with those of the capacitors with standard top SrRuO3 (SRO)/Au electrode. Pyroelectric measurements show that the pyroelectric signal recorded on ferroelectric capacitors with top CBSE electrode is 2.5 times greater than for top SRO/Au electrode for low frequency range. The value of the pyroelectric coefficient was estimated to 9.73·10-4 C/m2K for CBSE electrodes and 3.36·10-4 C/m2K for SRO/Au respectively. The fabrication process of CBSE is of low cost, easy to implement and with high throughput making it attractive for manufacturing various devices like pyroelectric detector, thermal imaging, solar cells, etc.
Collapse
Affiliation(s)
- C. Chirila
- National Institute of Materials Physics, Magurele-Ilfov Romania
- * E-mail:
| | - M. Botea
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - A. Iuga
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - A. G. Tomulescu
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - L. Balescu
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - A. C. Galca
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - A. G. Boni
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - L. Leonat
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - I. Pintilie
- National Institute of Materials Physics, Magurele-Ilfov Romania
| | - L. Pintilie
- National Institute of Materials Physics, Magurele-Ilfov Romania
| |
Collapse
|
10
|
Krause B, Rzeczkowski P, Pötschke P. Thermal Conductivity and Electrical Resistivity of Melt-Mixed Polypropylene Composites Containing Mixtures of Carbon-Based Fillers. Polymers (Basel) 2019; 11:polym11061073. [PMID: 31234343 PMCID: PMC6630210 DOI: 10.3390/polym11061073] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 11/16/2022] Open
Abstract
Melt-mixed composites based on polypropylene (PP) with various carbon-based fillers were investigated with regard to their thermal conductivity and electrical resistivity. The composites were filled with up to three fillers by selecting combinations of graphite nanoplatelets (GNP), carbon fibers (CF), carbon nanotubes (CNT), carbon black (CB), and graphite (G) at a constant filler content of 7.5 vol%. The thermal conductivity of PP (0.26 W/(m·K)) improved most using graphite nanoplatelets, whereas electrical resistivity was the lowest when using multiwalled CNT. Synergistic effects could be observed for different filler combinations. The PP composite, which contains a mixture of GNP, CNT, and highly structured CB, simultaneously had high thermal conductivity (0.5 W/(m·K)) and the lowest electrical volume resistivity (4 Ohm·cm).
Collapse
Affiliation(s)
- Beate Krause
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany.
| | - Piotr Rzeczkowski
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany.
| | - Petra Pötschke
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, 01069 Dresden, Germany.
| |
Collapse
|
11
|
Li Y, Pötschke P, Pionteck J, Voit B. Electrical and vapor sensing behaviors of polycarbonate composites containing hybrid carbon fillers. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.09.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
12
|
Müller MT, Pötzsch HF, Gohs U, Heinrich G. Online Structural-Health Monitoring of Glass Fiber-Reinforced Thermoplastics Using Different Carbon Allotropes in the Interphase. MATERIALS 2018; 11:ma11071075. [PMID: 29941808 PMCID: PMC6073548 DOI: 10.3390/ma11071075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/04/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022]
Abstract
An electromechanical response behavior is realized by nanostructuring the glass fiber interphase with different highly electrically conductive carbon allotropes like carbon nanotubes (CNT), graphene nanoplatelets (GNP), or conductive carbon black (CB). The operational capability of these multifunctional glass fibers for an online structural-health monitoring is demonstrated in endless glass fiber-reinforced polypropylene. The electromechanical response behavior, during a static or dynamic three-point bending test of various carbon modifications, shows qualitative differences in the signal quality and sensitivity due to the different aspect ratios of the nanoparticles and the associated electrically conductive network densities in the interphase. Depending on the embedding position within the glass fiber-reinforced composite compression, shear and tension loadings of the fibers can be distinguished by different characteristics of the corresponding electrical signal. The occurrence of irreversible signal changes during the dynamic loading can be attributed to filler reorientation processes caused by polymer creeping or by destruction of electrically conductive paths by cracks in the glass fiber interphase.
Collapse
Affiliation(s)
- Michael Thomas Müller
- Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden, Germany.
| | - Hendrik Florian Pötzsch
- Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden, Germany.
- Institute of Textile Machinery and High Performance Material Technology, Technische Universität Dresden, D-01062 Dresden, Germany.
| | - Uwe Gohs
- Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden, Germany.
| | - Gert Heinrich
- Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, D-01069 Dresden, Germany.
- Institute of Textile Machinery and High Performance Material Technology, Technische Universität Dresden, D-01062 Dresden, Germany.
| |
Collapse
|
13
|
Hamidinejad M, Zhao B, Chu RKM, Moghimian N, Naguib HE, Filleter T, Park CB. Ultralight Microcellular Polymer-Graphene Nanoplatelet Foams with Enhanced Dielectric Performance. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19987-19998. [PMID: 29745647 DOI: 10.1021/acsami.8b03777] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Dielectric polymer nanocomposites with high dielectric constant (ε') and low dielectric loss (tan δ) are extremely desirable in the electronics industry. Percolative polymer-graphene nanoplatelet (GnP) composites have shown great promise as dielectric materials for high-performance capacitors. Herein, an industrially-viable technique for manufacturing a new class of ultralight polymer composite foams using commercial GnPs with excellent dielectric performance is presented. Using this method, the high-density polyethylene (HDPE)-GnPs composites with a microcellular structure were fabricated by melt-mixing. This was followed by supercritical fluid (SCF) treatment and physical foaming in an extrusion process, which added an extra layer of design flexibility. The SCF treatment effectively in situ exfoliated the GnPs in the polymer matrix. Moreover, the generation of a microcellular structure produced numerous parallel-plate nanocapacitors consisting of GnP pairs as electrodes with insulating polymer as nanodielectrics. This significantly increased the real permittivity and decreased the dielectric loss. The ultralight extruded HDPE-1.08 vol % GnP composite foams, with a 0.15 g·cm-3 density, had an excellent combination of dielectric properties (ε' = 77.5, tan δ = 0.003 at 1 × 105 Hz), which were superior to their compression-molded counterparts (ε' = 19.9, tan δ = 0.15 and density of = 1.2 g·cm-3) and to those reported in the literature. This dramatic improvement resulted from in situ GnP's exfoliation and dispersion, as well as a unique GnP parallel-plate arrangement around the cells. Thus, this facile method provides a scalable method to produce ultralight dielectric polymer nanocomposites, with a microscopically tailored microstructure for use in electronic devices.
Collapse
Affiliation(s)
| | | | | | - Nima Moghimian
- NanoXplore Inc. , 25 Boul. Montpellier , Saint-Laurent , Quebec H4N 2G3 , Canada
| | | | | | | |
Collapse
|
14
|
Carbon-Based Oxamate Cobalt(III) Complexes as Bioenzyme Mimics for Contaminant Elimination in High Backgrounds of Complicated Constituents. MATERIALS 2017; 10:ma10101169. [PMID: 29023394 PMCID: PMC5666975 DOI: 10.3390/ma10101169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/20/2017] [Accepted: 09/30/2017] [Indexed: 11/16/2022]
Abstract
Complex wastewater with massive components is now a serious environmental issue facing humanity. Selective removal of low-concentration contaminants in mixed constituents holds great promise for increasing water supplies. Bioenzymes like horseradish peroxidase exhibit oxidizing power and selectivity. Here, we manufactured its mimic through immobilizing non-heme oxamate anionic cobalt(III) complex ([CoIII(opba)]−, opba = o-phenylenebis(oxamate)) onto pyridine (Py) modified multiwalled carbon nanotubes ([CoIII(opba)]−-Py-MWCNTs, MWCNTs = multiwalled carbon nanotubes), where MWCNTs captured substrates and Py functioned as the fifth ligand. We chose typical azo dye (C.I. Acid Red 1) and antibiotic (ciprofloxacin) as model substrates. Without •OH, this catalyst could detoxify target micropollutants efficiently at pH from 8 to 11. It also remained efficient in repetitive tests, and the final products were non-poisonous OH-containing acids. Combined with radical scavenger tests and electron paramagnetic resonance result, we speculated that high-valent cobalt-oxo active species and oxygen atom transfer reaction dominated in the reaction pathway. According to density functional theory calculations, the electron spin density distribution order showed that electron-withdrawing ligand was beneficial for inward pulling the excess electron and lowering the corresponding energy levels, achieving an electrophilic-attack enhancement of the catalyst. With target removal property and recyclability, this catalyst is prospective in water detoxication.
Collapse
|
15
|
Liebscher M, Domurath J, Krause B, Saphiannikova M, Heinrich G, Pötschke P. Electrical and melt rheological characterization of PC and co-continuous PC/SAN blends filled with CNTs: Relationship between melt-mixing parameters, filler dispersion, and filler aspect ratio. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/polb.24515] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Marco Liebscher
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
- Technische Universität Dresden; Dresden D-01062 Germany
| | - Jan Domurath
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
- Institut de Recherche Dupuy de Lôme (IRDL), Univ. Bretagne Sud, FRE CNRS 3744, IRDL; Lorient F-56100 France
| | - Beate Krause
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
| | - Marina Saphiannikova
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
| | - Gert Heinrich
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
- Technische Universität Dresden; Dresden D-01062 Germany
| | - Petra Pötschke
- Leibniz-Institut für Polymerforschung Dresden e.V. (Leibniz Institute of Polymer Research Dresden, IPF), Hohe Str. 6; Dresden D-01069 Germany
| |
Collapse
|