TY - JOUR A1 - Goedecke, Caroline A1 - Mülow-Stollin, Ulrike A1 - Hering, S. A1 - Richter, Janine A1 - Piechotta, Christian A1 - Paul, Andrea A1 - Braun, Ulrike T1 - A first pilot study on the sorption of environmental pollutants on various microplastic materials N2 - With the drastic increase in plastic production, the input of plastic particles into the environment has become a recognised problem. Xenobiotics are able to sorb to polymer materials, and this process is further enhanced where they Encounter microplastics (plastic fragments <5 mm). In this work we studied the sorption of metformin, a type-2 diabetes drug, and difenoconazole, a fungicide, onto the virgin polymer materials polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, PP was cryo-milled and PA was treated with acid to investigate the influence of an increase in surface area and chemical modification. The material properties were also studied by dynamic scanning calorimetry (DSC), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). Sorption experiments were performed on the basis of a full factorial design examining the effect of agitation, pH value, and salinity. Experimental results showed that difenoconazole sorbs readily to all microplastics, whereas the more polar analyte metformin did not show any affinity to the materials used. For difenoconazole the governing factor in all cases is agitation, while both pH and salinity exhibited only a slight influence. The modification of polymers leads to enhanced sorption, indicating that an increase in surface area (cryo-milled PP) or inner volume (acid-treated PA) strongly favours adsorption. Moreover, long-term experiments demonstrated that the time until equilibrium is reached depends strongly on the particle size. KW - Difenoconazole KW - Metformin KW - Plastic debris KW - Polymer KW - Dynamic scanning calorimetry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402393 DO - https://doi.org/10.4172/2380-2391.1000191 SN - 2380-2391 VL - 4 IS - 1 SP - Article 1000191, 1 EP - 8 PB - Omics International CY - Los Angeles AN - OPUS4-40239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Braun, Ulrike T1 - Wirkungsmechanismen von Rotem Phosphor als Flammschutzmittel in Thermoplasten N2 - Das Brandverhalten von Rotem Phosphor in HIPS, PBT und PA66 wurde untersucht. Es wurde gezeigt, wie die Wirksamkeit von Rotem Phosphor in HIPS and PBT durch Kombination mit anderen Flammschutzmitteln zu verbessern ist. N2 - Polymers are flammable due to their chemical nature. As a consequence they must be treated with flame-retardants before they can be used in fields with high flammability risks, such as transport, electronic devices and building construction. The use of red phosphorus as a fire retardant has been encouraged because it is an environmentally friendly alternative to halogenated compounds. The intention of this thesis was to evaluate the potential of red phosphorus as a flame retardant and to determine its fire-retardant mechanisms in different thermoplastics. The thermal decomposition and combustion behaviour of HIPS, PBT and PA66 containing red phosphorus was studied. It further investigated how the activity and efficiency of red phosphorus in HIPS and PBT was influenced by additional flame retardants such as melamine polyphosphate, melamine cyanurate and magnesium hydroxide. The decomposition process was characterized by means of different thermogravimetric methods (TG-FTIR, TG-MS), and the combustion behaviour by cone calorimeter measurements at various external heat fluxes. The flammability was investigated with LOI and the residue of combustion was analysed by means of XPS. Based on these results models for decomposition process were postulated. Red phosphorus can act both by promoting char formation in the condensed phase, and through radical trapping in the gas phase. Red phosphorus acts in the condensed phase in PA66, and in the gas phase in HIPS. In PBT both mechanisms were observed, depending on the pH value. When red phosphorus is combined with fuel-dilution additives such as melamine species in HIPS and PBT, both flame retardants act independently. The combustion behaviour of the combined material can be described by superposition of the distinct flame-retarded materials. In the presence of a barrier former, such as magnesium hydroxide in HIPS, the gas-phase mechanism of red phosphorus remains unaffected; however, a slight anti-synergism results. This is based on formation of a magnesium phosphate barrier, which influences the efficiency of phosphorus as a radical trap. The results showed that the activity of phosphorus as a flame retardant in thermoplastics depends on the water content of the polymer, the pH value and the presence of functional groups in the polymer. The efficiency of phosphorus as a flame retardant in the condensed and gas phases depends on combustion conditions. T3 - BAM Dissertationsreihe - 10 KW - Roter Phosphor KW - Flammschutzmittel KW - Thermoplasten PY - 2005 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-1486 SN - 978-3-86509-303-5 SN - 1613-4249 VL - 10 SP - 1 EP - 164 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-148 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Phosphorus components as flame retardant T2 - BASF - Flammschutzseminar CY - Ludwigshafen am Rhein, Germany DA - 2006-07-13 PY - 2006 AN - OPUS4-12569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Beständigkeit von Medizinprodukten T2 - Life Science Day 2012 CY - Berlin, Germany DA - 2012-06-08 PY - 2012 AN - OPUS4-26013 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Beständigkeit von Polymeren: Verständnis molekularer Mechanismen T2 - JKU, Institute of Polymeric Materials and Testing, Seminar lecture CY - Linz, Austria DA - 2013-05-29 PY - 2013 AN - OPUS4-28603 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang A1 - Teteris, Gundars A1 - Braun, Ulrike A1 - Bohmeyer, W. A1 - Lange, K. T1 - Kontrolle der Vernetzungsreaktion bei reaktiven Harzen - DSC, Rheologie, DMA, FTIR und Online-Ultraschall im Vergleich N2 - Faserverbundbauteile werden durch Tränkung von Fasergewebe mit flüssigem Harz, in der Regel Epoxidharzen, und anschließender Härtung des Harzes gefertigt. Dabei kann man das Gewebe im Vorfeld mit reaktivem Harz tränken und als so genanntes Prepreg verarbeiten oder man injiziert das frisch mit dem Härter gemischte Harz in ein Werkzeug, in dem das Gewebe bereits liegt - z. B. beim RTM-Prozess. Ausgehend von der Aufgabenstellung, eine Prepregherstellung mit hohem Qualitätsstandard zu realisieren und Möglichkeiten der Fertigungskontrolle für den Prepreg-Verarbeiter aufzuzeigen, wurde an einem für die Prepregherstellung vorgesehenen Harzsystem eine weitgehende Charakterisierung des Aushärtungsverlaufs vorgenommen. Wegen der Schwierigkeit, schnell konstante Aushärtungstemperaturen zu erreichen, wurden bei allen Methoden mit einer Heizrate von 1 K/min von RT bis 200 °C aufgeheizt. T2 - Technomer 2011 - 22. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Deutschland DA - 10.11.2011 KW - Thermoanalyse KW - Lineare Aufheizung KW - Online Prozesskontrolle KW - Epoxidharz KW - Prepreg PY - 2011 SN - 978-3-939382-10-2 IS - Kap. 1.1 SP - 1 EP - 9 AN - OPUS4-24910 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seefeldt, Henrik A1 - Braun, Ulrike A1 - Wagner, M.H. T1 - Residue stabilization in the fire retardancy of wood-plastic composites: combination of ammonium polyphosphate, expandable graphite, and red phosphorus N2 - Combinations of different common flame retardants in wood–plastic composites (WPCs) are tested to identify synergistic or antagonistic effects with the goal of improving the fire performance of WPCs. Flame retardants investigated are expandable graphite (EG), ammonium polyphosphate (APP), and red phosphorus (RP) and combinations of two of them are used. The fire behavior is studied by cone calorimetric measurements. Additional thermogravimetry is used for further investigations. The fire tests show that EG has the highest potential for flame retardancy, but due to its expansion it cracks the formed residue layer. Combinations of EG with RP or with high amounts of APP are able to suppress this cracking. KW - Flame retardance KW - Halogen free KW - Renewable resources KW - Wood-plastic composites KW - WPC PY - 2012 DO - https://doi.org/10.1002/macp.201200119 SN - 1022-1352 SN - 1521-3935 VL - 213 IS - 22 SP - 2370 EP - 2377 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Wirkungsmechanismen von Rotem Phosphor als Flammschutzmittel in Polymeren T2 - Disputation im Rahmen des Promotionsverfahrens am Institut für Chemie der FU Berlin CY - Berlin, Germany DA - 2004-12-01 PY - 2004 AN - OPUS4-6370 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Roter Phosphor als Flammschutzmittel? T2 - Vortragsreihe im Institut für Chemie der FU Berlin CY - Berlin, Germany DA - 2004-10-22 PY - 2004 AN - OPUS4-6394 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Understanding the Molecular Degradation Behavior of Polymers T2 - BASF Flammschutztag CY - Mannheim, Germany DA - 2013-10-28 PY - 2013 AN - OPUS4-29330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seefeldt, Henrik A1 - Dümichen, Erik A1 - Braun, Ulrike T1 - Flame retardancy of glass fiber reinforced high temperature polyamide by use of aluminum diethylphosphinate: thermal and thermo-oxidative effects N2 - Glass fiber reinforced polyamide (PA) 6T/DT flame retarded with aluminum diethylphosphinate (AlPi) was tested to assess its flame retardant properties. Models for the decomposition of PA 6T/DT with and without AlPi are presented. Thermal decomposition was measured by performing TGA with Fourier transform infrared (FTIR) spectroscopy and FTIR spectroscopy in the condensed phase. Fire behavior was studied using a cone calorimeter and flammability was tested with UL 94 and the limiting oxygen index. AlPi works as an effective flame retardant for glass fiber reinforced PA 6T/DT materials, acting in the gas phase. Also observed was condensed-phase action, which occurs especially under oxidative conditions before the samples ignite. KW - Flame retardancy KW - High tmeperature polyamide 6T/DT KW - Aluminum phosphinate KW - Degradation PY - 2013 DO - https://doi.org/10.1002/pi.4497 SN - 0959-8103 SN - 1097-0126 SN - 0007-1641 VL - 62 IS - 11 SP - 1608 EP - 1616 PB - Wiley InterScience CY - Chichester, West Sussex AN - OPUS4-29386 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike A1 - Lorenz, Edelgard A1 - Bajer, Kamila A1 - Kneip, Gisela A1 - Rybak, Thomas T1 - Understanding the molecular degradation behaviour of polyolefin using autoclave tests at various pressures and temperatures T2 - Polymer Degradation and Discussion Group (PDDG) CY - Paris, France DA - 2013-09-01 PY - 2013 AN - OPUS4-29106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike A1 - Böhning, Martin T1 - Durability of Thermoplastic Polyurethanes (TPU) T2 - Polydays 2010 CY - Berlin, Germany DA - 2010-10-03 PY - 2010 AN - OPUS4-22107 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seefeldt, Henrik A1 - Braun, Ulrike T1 - A new flame retardant for wood materials tested in wood-plastic composites N2 - A new flame retardant based on an ammonium phosphonate is studied with respect to its thermal decomposition and its mode of action in wood-plastic composites (WPCs). The measurements are carried out by means of fire tests (cone calorimeter) and pyrolysis investigations (thermogravimetry, infrared spectroscopy). The flame retardant acts mainly in the condensed phase by increasing the amount of residue formed by the wood part in the WPC. Additional flame dilution is achieved by the release of water, ammonia and carbon dioxide during the decomposition of the flame retardant. KW - Disflamoll TP LXS 51064 KW - Flame retardance KW - Thermogravimetric analysis (TGA) KW - Wood-plastic composites (WPC) PY - 2012 DO - https://doi.org/10.1002/mame.201100382 SN - 1438-7492 SN - 1439-2054 VL - 297 IS - 8 SP - 814 EP - 820 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-26566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Beständigkeit von Polymeren: Aushärtungs- und Degradationskontrolle T2 - Workshop am Fraunhofer CSP CY - Halle (Saale), Germany DA - 2012-11-06 PY - 2012 AN - OPUS4-26917 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seefeldt, Henrik A1 - Braun, Ulrike T1 - Burning behavior of wood-plastic composite decking boards in end-use conditions: the effects of geometry, material composition, and moisture N2 - In this study, we investigated the basic knowledge necessary to develop flame-retarded wood–plastic composite (WPC) materials by focusing on decking boards. Therefore, the respective effects of geometry, material composition, and moisture were studied by performing cone calorimetric measurements. Using hollow-shaped geometries removes combustible material and reduces the fire load but simultaneously increases fire propagation. The best results were achieved by using high-wood contents. The addition of talc can reduce the intensity of burning. Moisture also has a positive effect on burning behavior. Apart from the well-known mechanism of water, a change was observed in the resultant residue. KW - WPC KW - Wood-plastic composite KW - Cone calorimeter KW - Decking boards PY - 2012 DO - https://doi.org/10.1177/0734904111423488 SN - 0734-9041 SN - 1530-8049 VL - 30 IS - 1 SP - 41 EP - 54 PB - Sage CY - London AN - OPUS4-25357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike A1 - Lorenz, Edelgard A1 - Kneip, Gisela A1 - Rybak, Thomas T1 - Time-Dependent Structure Changes of Polymers for Medical Application During their Life Cycle T2 - MODEST 2012 CY - Prague, Czech Republic DA - 2012-09-02 PY - 2012 AN - OPUS4-26444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, S. A1 - Timmel, S. A1 - Richter, S. A1 - Werner, M. A1 - Gläser, M. A1 - Swatek, S. A1 - Braun, Ulrike A1 - Hagendorf, C. T1 - Silver nanoparticles cause snail trails in photovoltaic modules N2 - After some months of operation, a number of PV modules develop a discolouration defect called 'snail trails', or 'snail traces', which appear as irregular dark stripes across the cells. Whereas these traces were soon identified as discoloured silver contacts along the cell edges or at micro cracks, the chemical and mechanistic reasons for this phenomenon have not yet been resolved in detail. In this work we show that silver nanoparticles accumulating within the encapsulation foil cause the brownish discolouration, and that certain additives of encapsulation and back sheet foils trigger the formation of these nanoparticles. KW - Snail trails KW - Cell cracks KW - Encapsulation foil KW - Ag contact finger KW - Nanoparticles PY - 2014 DO - https://doi.org/10.1016/j.solmat.2013.11.013 SN - 0927-0248 VL - 121 SP - 171 EP - 175 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-30059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike A1 - Dümichen, Erik A1 - Eisentraut, Paul A1 - Barthel, Anne-Kathrin A1 - Bannick, Claus Gerhard T1 - Mikroplastik: Ein Material oder ein Problem? N2 - Durch den stetig steigenden Einsatz von Plastikprodukten sind unerwünschte Kunststofffunde in verschiedenen Umweltmatrices mittlerweile allgegenwärtig. Bereits seit Jahren werden die Funde in aquatischen Bereich kommentiert, mittlerweile erfahren auch terrestrische Kompartimente erhöhte Aufmerksamkeit. Besonderes Interesse erfahren Kunststoffpartikel von einer Größe kleiner 5 mm, sogenannte Mikroplastik (MP) Partikel. T2 - Kunststofftechnisches Kolloquium CY - Chemnitz, Germany DA - 10.05.2016 KW - Mikroplastik KW - Polymere PY - 2016 AN - OPUS4-36757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koshkina, Olga A1 - Westmeier, D. A1 - Lang, Thomas A1 - Bantz, C. A1 - Hahlbrock, A. A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Braun, Ulrike A1 - Thiermann, Raphael A1 - Weise, C. A1 - Eravci, M. A1 - Mohr, B. A1 - Schlaad, H. A1 - Stauber, R. H. A1 - Docter, D. A1 - Bertin, Annabelle A1 - Maskos, M. T1 - Tuning the surface of nanoparticles: Impact of poly(2-ethyl-2-oxazoline) on protein adsorption in serum and cellular uptake N2 - Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach. With multi-angle dynamic light scattering, asymmetrical flow field-flow fractionation, gel electrophoresis, and liquid chromatography-mass spectrometry, it is demonstrated that protein adsorption on PEtOxylated nanoparticles is extremely low, similar as on PEGylated nanoparticles. Moreover, quantitative microscopy reveals that PEtOxylation significantly reduces the non-specific cellular uptake, particularly by macrophage-like cells. Collectively, studies demonstrate that PEtOx is a very effective alternative to PEG for stealth modification of the surface of nanoparticles. KW - Poloxazolines KW - Protein corona KW - Cellular uptake PY - 2016 DO - https://doi.org/10.1002/mabi.201600074 SN - 1616-5187 SN - 1616-5195 VL - 16 IS - 9 SP - 1287 EP - 1300 AN - OPUS4-37369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -