Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-29386 Zeitschriftenartikel Seefeldt, Henrik; Dümichen, Erik; Braun, Ulrike Flame retardancy of glass fiber reinforced high temperature polyamide by use of aluminum diethylphosphinate: thermal and thermo-oxidative effects 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. Chichester, West Sussex Wiley InterScience Society of Chemical Industry 2013 Polymer International 62 11 1608 1616 10.1002/pi.4497 2016-02-20 OPUS4-29078 Posterpräsentation Dümichen, Erik Investigation of the Degradation Mechanism of Transition Metal Doped Polyamides and Polyesters 2013 PDDG PDDG Paris, France 2013-09-01 2013-09-04 2016-02-20 OPUS4-37314 Vortrag Dümichen, Erik Identification of microplastics in the environment The worldwide produced plastic amount was about 314 m tones in 2013. A content of about 5-12 m tones of plastic products is estimated to attain to the environment. There, they are exposed to environmental aging conditions like UV light, abrasion, water, oxidation etc. and degrade to small particles. If the particles reach a dimension < 5 mm they are called microplastic. Today microplastic is almost ubiquitary and was found in the aquatic as well as in the terrestrial environment. The main representatives are polyethylene (PE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalat (PET). Analyzing microplastics in environmental samples turned out to be very challenging, due to the fact that there are only a few synthetic particles beside a huge number of natural. Furthermore, the different polymers particles vary in their shape, their density and their chemical characteristics. Until now, there is no standard procedure for sampling, concentration and analyzing. We developed a thermal decomposition method for analyzing micro plastics in environmental samples. The method is a combination of a thermal extraction on solid-phase adsorption agents with a subsequent analysis of the decomposition products by thermal desorption gas chromatography mass spectrometry. In contrast to more established methods, such as IR or Ramen spectroscopy, our method enables measurements within few hours and gives an integration result of polymer specific decomposition products. Therefore, it is possible to identify and to quantify polymers in environmental matrices. The use of the method is demonstrated for various polymers (PE, PP, PS, PET) in spiked and first time also in real environmental samples. 2016 MoDeSt 2016 Krakau, Poland 04.09.2016 08.09.2016 2016-09-12 OPUS4-36782 Beitrag zu einem Tagungsband Braun, Ulrike; Dümichen, Erik; Barthel, Anne-Kathrin; Bannick, Claus Gerhard Charakterisierung von Mikroplastik Partikeln aus Umweltproben Durch den stetig steigenden Einsatz von Plastikprodukten sind unerwünschte Kunststofffunde in verschiedenen Umweltmatrices mittlerweile allgegenwärtig. Besonderes Interesse erfahren die Kunststoffpartikel von einer Größe kleiner 5 mm, sogenannte Mikroplastik (MP) Partikel. Es werden aktuell Risiken für Mensch und Umwelt diskutiert, die von diesen Partikeln ausgehen. Mülheim an der Ruhr, Germany Wasserchemische Gesellschaft Gesellschaft Deutscher Chemiker 2016 Wasser 2016 - Jahrestagung der Wasserchemischen Gesellschaft - Fachgruppe in der Gesellschaft Deutscher Chemiker / Wasserchemische Gesellschaft - FG in der GDCh 978-3-936028-94-2 Wasser 2016 - Jahrestagung der Wasserchemischen Gesellschaft Bamberg, Deutschland 02.05.2016 04.05.2016 74 76 2016-07-07 OPUS4-31501 Vortrag Dümichen, Erik The impact of metal oxide particles on the thermal and thermo-oxidative degradation of polyamide 66 2014 MoDeSt 2014 MoDeSt 2014 Portoro˛, Slovenia 2014-08-31 2014-09-04 2016-02-20 OPUS4-31502 Vortrag Dümichen, Erik Decomposition gas analysis of polymers by thermogravimetry solid-phase extraction thermal desorption gas chromatography mass spectrometry (TGA-SPE/TDS-GC-MS) 2014 GEFTA 2014 (Gesellschaft für Thermische Analyse e. V.) GEFTA 2014 (Gesellschaft für Thermische Analyse e. V.) Berlin, Germany 2014-09-16 2014-09-19 2016-02-20 OPUS4-31046 Zeitschriftenartikel Dümichen, Erik; Braun, Ulrike; Senz, R.; Fabian, G.; Sturm, Heinz Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. Amsterdam Elsevier B.V. 2014 Journal of chromatography A 1354 117 128 10.1016/j.chroma.2014.05.057 2016-02-20 OPUS4-21522 Posterpräsentation Dümichen, Erik Investigation of a flame retardant high-temperature polyamide 2010 Tag der Chemie Tag der Chemie Berlin, Germany 2010-06-16 2016-02-19 OPUS4-33758 Vortrag Dümichen, Erik Analyzing the thermal- and thermo-oxidative degradation of polymers by a combination of thermal solid-phase extraction and thermal desorptiion (TED-GC-MS) 2015 Interantional Summit on Current Trends in Mass Spectrometry Interantional Summit on Current Trends in Mass Spectrometry New Orleans, USA 2015-07-13 2015-07-15 2016-02-20 OPUS4-34288 Posterpräsentation Dümichen, Erik Mikrobielle Besiedlung von Mikroplastik aus kommerziellen Produkten 2015 Fluss. Stadt. Land. Gewässer im Wandel - Jahrestagung der Deutschen Gesellschaft für Limnologie und der deutschsprachigen Sektionen der SIL Fluss. Stadt. Land. Gewässer im Wandel - Jahrestagung der Deutschen Gesellschaft für Limnologie und der deutschsprachigen Sektionen der SIL Essen, Deutschland 2015-09-21 2015-09-25 2016-02-20 OPUS4-34505 Posterpräsentation Dümichen, Erik Non Isothermal Cure Kinetics of an Epoxy/Amine Resin by In Situ Near Infrared Spectroscopy 2015 PDDG 2015 PDDG 2015 Stockholm, Sweden 2015-08-30 2015-09-03 2016-02-20 OPUS4-33105 Zeitschriftenartikel Bannick, Claus Gerhard; Bierl, R.; Braun, Ulrike; Brand, K.; Dümichen, Erik; Jekel, M.; Klein, S.; Knepper, T.P.; König, F.; Miklos, D.; Rechenberg, B.; Steffens, I. Mikroplastik in der aquatischen Umwelt - Ein Beitrag zur aktuellen Diskussion in Deutschland Plastics are important materials in households and industry and therefore a crucial part of our everyday life. Since the beginning of the 1970s the occurrence of plastic particles in coastal waters has been explicitly described. Meanwhile, besides the marine environment, microplastics were also detected in other environmental media, biota and water management facilities. This work gives an overview of the occurrence and first known effects of microplastics in the environment. Furthermore, current scientific proceedings are considered and pending issues are discussed. In this regard it is of central importance to develop an environmentally comprehensive, harmonized scientific proceeding for miroplastics, which enables an evaluation of relevant material flows in adaption to necessary assessment concepts. Weinheim Wiley-VCH Verl. Wasserchemische Gesellschaft 2015 Vom Wasser 113 1 7 14 2016-02-20 OPUS4-32334 Vortrag Dümichen, Erik Prüfung der Beständigkeit von Kunststoffen im täglichen Gebrauch - thermische Analyseverfahren und Anwendungen an der Bundesanstalt für Materialforschung und -prüfung 2014 Campus Bizz, Hochschule Hamm-Lippstadt Campus Bizz, Hochschule Hamm-Lippstadt Hamm-Lippstadt, Deutschland 2014-12-16 2016-02-20 OPUS4-34337 Zeitschriftenartikel Dümichen, Erik; Barthel, Anne-Kathrin; Braun, Ulrike; Bannick, Claus Gerhard; Brand, K.; Jekel, M.; Senz, R. Analysis of polyethylene microplastics in environmental samples, using a thermal decomposition method Small polymer particles with a diameter of less than 5 mm called microplastics find their way into the environment from polymer debris and industrial production. Therefore a method is needed to identify and quantify microplastics in various environmental samples to generate reliable concentration values. Such concentration values, i.e. quantitative results, are necessary for an assessment of microplastic in environmental media. This was achieved by thermal extraction in thermogravimetric analysis (TGA), connected to a solid-phase adsorber. These adsorbers were subsequently analysed by thermal desorption gas chromatography mass spectrometry (TDS-GC-MS). In comparison to other chromatographic methods, like pyrolyse gas chromatography mass spectrometry (Py-GC-MS), the relatively high sample masses in TGA (about 200 times higher than used in Py-GC-MS) analysed here enable the measurement of complex matrices that are not homogenous on a small scale. Through the characteristic decomposition products known for every kind of polymer it is possible to identify and even to quantify polymer particles in various matrices. Polyethylene (PE), one of the most important representatives for microplastics, was chosen as an example for identification and quantification. Amsterdam Elsevier Ltd. International Association on Water Pollution Research 2015 Water research 85 451 457 10.1016/j.watres.2015.09.002 2016-02-20 OPUS4-34338 Zeitschriftenartikel Dümichen, Erik; Braun, Ulrike; Kraemer, R.; Deglmann, P.; Senz, R. Thermal extraction combined with thermal desorption: A powerful tool to investigate the thermo-oxidative degradation of polyamide 66 materials Using thermogravimetric analysis (TGA) with a solid-phase adsorber for thermal extraction, followed by subsequently analysing the adsorber with thermo-desorption gas chromatography mass spectrometry (TDS-GC–MS) enables measurement of polymer degradation under oxidizing atmosphere, and the identification of certain complex hydrocarbon degradation products by chromatographic separation and defined mass patterns. This technique, thermal-extraction desorption gas chromatography mass spectrometry (TED-GC–MS) was used to investigate the thermo-oxidative degradation of PA 66 and PA 66 doped with 2 wt% of metal oxide particles. In TGA pure PA 66 formed more residue under an oxidizing atmosphere than an inert one. In contrast to the measurements under inert atmosphere, several condensed aromatic species containing nitrogen could be identified in thermo-oxidative measurements. These degradation products were formed through condensation reactions of primary amides originating from imide hydrolysis. The formation of such highly condensed species also causes higher char formation. Four metal oxides have shown an impact on the thermo-oxidative degradation of PA 66: Fe2O3 on η-Al2O3 < pure Fe2O3 = Fe2O3 on γ-Al2O3 < pure ZnO. For ZnO even a char-stabilizing effect could be observed. A catalytic effect of these metal oxides causes more condensed cyclopentanone and pyridine derivates. Thus, more water is formed and released, resulting in increased hydrolysis of the imides and degradation at lower temperatures. Amsterdam Elsevier B.V. 2015 Journal of analytical and applied pyrolysis 115 288 298 10.1016/j.jaap.2015.08.006 2016-02-20 OPUS4-34310 Vortrag Dümichen, Erik Methoden zur Identifizierung und Quantifizierung von Mikroplastik in der Umwelt 2015 Fluss. Stadt. Land - Gewässer im Wandel - Jahrestagung der Deutschan Gesellschaft für Limnologie und der deutschsprachigen Sektion der SIL Fluss. Stadt. Land - Gewässer im Wandel - Jahrestagung der Deutschan Gesellschaft für Limnologie und der deutschsprachigen Sektion der SIL Essen, Deutschland 2015-09-21 2015-09-25 2016-02-20 OPUS4-34187 Zeitschriftenartikel Dümichen, Erik; Javdanitehran, M.; Erdmann, Maren; Trappe, Volker; Sturm, Heinz; Braun, Ulrike; Ziegmann, G. Analyzing the network formation and curing kinetics of epoxy resins by in situ near-infrared measurements with variable heating rates Near-infrared spectroscopy (NIR) turned out to be well suited for analyzing the degree of cure for epoxy systems. In contrast to dynamic scanning calorimetry (DSC), where the released heat of reaction determines the degree of epoxy conversion indirectly, NIR spectroscopy is able to determine the conversion directly by analyzing structural changes. Therefore, a new heatable NIR cell was equipped with an integrated thermocouple, which enables the real sample temperature to be controlled and monitored in situ during epoxy curing. Dynamic scans at different heating rates were used for kinetic modelling, to define kinetic parameters and to predict real curing processes. The kinetic models and their parameters were validated with an isothermal and a more complex multi-step curing scenario. Two available commercial epoxy systems based on DGEBA were used with an anhydride and with an amine hardener. NIR results were compared with DSC data. The simulated conversion predicted with a model fitted on the basis of NIR and DSC dynamic scans showed good agreement with the conversion measured in the isothermal curing validation test. Due to the proven reliability of NIR in measuring the reaction progress of curing, it can be considered a versatile measurement system for in situ monitoring of component production in the automotive, aerospace and wind energy sectors. Amsterdam Elsevier 2015 Thermochimica Acta 616 49 60 10.1016/j.tca.2015.08.008 2016-02-20 OPUS4-33806 Zeitschriftenartikel Dümichen, Erik; Braun, Ulrike; Sturm, Heinz; Kraemer, R.; Deglmann, P.; Gaan, S.; Senz, R. A new molecular understanding of the thermal degradation of PA 66 doped with metal oxides: Experiment and computation The thermal molecular degradation of polyamide 66 (PA 66) doped with (partially supported) metal oxide particles (Fe2O3, ZnO, Al2O3) was investigated qualitatively and quantitatively using common analysis techniques like thermogravimetry coupled with IR-spectroscopic evolved gas analysis (TGA-FTIR). Using pyrolysis coupled with gas chromatography mass spectrometry (Py-GC-MS), qualitative conclusions were drawn about the complex hydrocarbon products. However, the combination of TGA with solid-phase extraction, followed by thermal desorption gas chromatography mass spectrometry (TED-GC-MS), allows qualitative and even semi-quantitative conclusions about the decomposition pathway of PA 66 in the presence of various metal oxide particles. The investigations under inert conditions showed that the presence of metal particles increases the rate of decarboxylation and deamination reactions, as well as the formation rate of cyclopentanone and pyridine derivatives. These species are a consequence of various condensation reactions. The condensation reactions release a large amount of water, thus triggering the hydrolysis of PA 66. Molecular thermal degradation mechanisms were developed for the main decomposition as well as for the condensation reactions and supported by quantum chemical calculations. The catalytic effect of the metal oxides in PA 66 increases in the following order: PA 66 = PA 66 - Al2O3 < PA 66 - Fe2O3 < PA 66 - ZnO. London Elsevier Ltd. 2015 Polymer degradation and stability 120 340 356 10.1016/j.polymdegradstab.2015.07.011 2016-02-20 OPUS4-39123 Zeitschriftenartikel Erdmann, Maren; Trappe, Volker; Sturm, Heinz; Braun, Ulrike; Dümichen, Erik Cure conversion of structural epoxies by cure state analysis and in situ cure kinetics using nondestructive NIR spectroscopy Non-isothermal heating rate kinetics was applied to two epoxy resin systems. In situ near-infrared (NIR) measurements were taken with a heatable NIR cell which allowed the cure to be monitored by characteristic absorption bands. An autocatalyzed reaction of the nth order was shown to describe the epoxy conversion curves. Differential Scanning Calorimetry (DSC) was used as a complementary method. The kinetic models developed by both NIR and DSC are in good accordance with experimental epoxy conversion in the in situ NIR setup for single and multiple cure temperature ramps. A linear calibration curve of the characteristic absorption bands of epoxy normalized to aromatic vibrations was introduced. The curing degree of structural epoxies that were cured according to an industrial temperature cure profile was determined by NIR using the calibration curve. The epoxy conversions of the structural components showed good agreement with the experimental in situ NIR. Several degrees of cure for structural specimens were evaluated by NIR and residual reaction enthalpy by DSC. We present the non-destructive NIR spectroscopy as an alternative to determine fast and non-destructive epoxy conversion, particularly suitable for high degrees of cure on structural components. Elsevier B.V. 2017 Thermochimica Acta 650 8 17 10.1016/j.tca.2017.01.010 2017-02-08 OPUS4-44179 Vortrag Dümichen, Erik Fast identification of microplastics using thermal extractions methods A new and full automated system for the analysis of microplastics in environmental samples is presented. 2018 BAM-BfR Seminar 2018 Berlin, Germany 15.02.2018 15.02.2018 2018-02-16 OPUS4-48287 Zeitschriftenartikel Dümichen, Erik; Eisentraut, Paul; Celina, M.; Braun, Ulrike Automated thermal extraction-desorption gas chromatography mass spectrometry: A multifunctional tool for comprehensive characterization of polymers and their degradation products The TED-GC-MS analysis is a two-step method. A sample is first decomposed in a thermogravimetric analyzer (TGA) and the gaseous decomposition products are then trapped on a solid-phase adsorber. Subsequently, the solid-phase adsorber is analyzed with thermal desorption gas chromatography mass spectrometry (TDU-GC-MS). This method is ideally suited for the analysis of polymers and their degradation processes. Here, a new entirely automated System is introduced which enables high sample throughput and reproducible automated fractioned collection of decomposition products. Strengths and limitations of the system configuration are elaborated via three examples focused on practical challenges in materials analysis and identification: i) separate analysis of the components of a wood-plastic-composite material, ii) quantitative determination of weight concentration of the constituents of a polymer blend and iii) quantitative analysis of model samples of microplastics in suspended particulate matter. Amsterdam Elsevier 2019 Journal of Chromatography A 1592 133 142 10.1016/j.chroma.2019.01.033 2019-06-26 OPUS4-35719 Zeitschriftenartikel Javdanitehran, M.; Berg, D. Ch.; Dümichen, Erik; Ziegmann, G. Javdanitehran, M. An iterative approach for isothermal curing kinetics modelling of an epoxy resin system In this work a novel iterative method for isothermal cure kinetic modelling of an epoxy resin system using differential scanning calorimetry (DSC) technique is presented. To reach the isothermal cure temperature, the sample has to be heated up from ambient temperature. This is commonly done with very high heat-up rates to minimise the time the sample reacts at temperatures other than the desired one. However, during heat up with high heating the amount of released energy rates cannot be measured directly because the shape of baseline is unknown. This means that the cure state at the beginning of the isothermal stage is unknown. For fast curing systems this unknown cure state causes significant inaccuracies in cure kinetics modelling. The presented iterative approach attempts to estimate the released enthalpy during heat-up of an isothermal run through an iterative numerical modelling of the heat-up phase. In each iteration the algorithm starts by estimating the enthalpy released during heat-up based on the recorded temperature profile and the calibrated model of the previous iteration. At the same time, it estimates the degree of cure at the end of the heat-up phase. Once the initial cure state is known the total heat of enthalpy can be recalculated for the current iteration. Subsequently the degree of cure and curing rate are re-evaluated with the newly estimated total enthalpy and used for determining the kinetics parameters. This is done by simultaneous fitting of the selected model to all experimental heat flow curves using a non-linear nonrestricted multivariable fitting method. The model with these new parameters is used again to estimate the released enthalpy and cure degree during the heat-up phase. The described loop is repeated until a predefined convergence criterion is satisfied. For modelling the reaction kinetics, the Kamal-Sourour equation accompanied with Rabinowitch approach to consider the diffusion effects is used. The diffusion reaction rate is modelled by the free volume model proposed by Huguenin and Klein. DiBenedetto model is applied to predict the Evolution of glass transition temperature against the degree of cure. In order to compensate the effect of the Initial values in the model's calibration, the algorithm is implemented in a routine, which assesses the quality of the fitting and consequently selects the cure kinetics parameter. The described algorithm and the Routine are implemented in MATLAB. This paper demonstrates the application of this approach for using cure kinetics modelling to predict the degree of cure and the glass transition temperature. It supports the obtained results with validation tests using isothermal, dynamic and combined temperature profiles. Elsevier B.V. 2016 Thermochimica Acta 2016 623 72 79 10.1016/j.tca.2015.11.014 2016-04-18 OPUS4-50435 Zeitschriftenartikel Campbell, C. G.; Jordon Astorga, D.; Dümichen, Erik; Celina, M. Thermoset materials characterization by thermal desorption or pyrolysis based gas chromatography-mass spectrometry methods Thermoset materials characterization is often limited to solid state analytical techniques such as IR, NMR, DSC, TGA and mechanical testing. Alternatively, their off-gassing behavior can also be evaluated using GC based techniques such as TD-GC-MS, allowing this method to be applied to thermoset materials analyses such as identification, aging characterization, and formulation optimization. As an overview, common thermoset materials were evaluated by analyzing their gaseous degradation products via TGA-based pyrolysis and subsequent TD-GC-MS for the identification of representative volatile signatures. It is thereby possible to distinguish different classes of phenolic materials or cured epoxy resins, as well as their amine or anhydride curatives. Additionally, this method enabled quantification of a volatile fragment (bisphenol A, BPA) which is associated with oxidation of epoxy/amine thermoset materials. The amount of evolved BPA increased linearly with aging time and this trend exhibits linear Arrhenius behavior over the temperature range (80-125 °C) studied, in agreement with oxidation sensitivies based on oxygen consumption data. Further, TD-GC-MS was used to explore how off-gassing of residual anhydride curative from an epoxy/anhydride material depends on formulation stoichiometry. Even in formulations that theoretically contained enough epoxy to consume all anhydride (1:1 stoichiometry), an imperfect final cure state resulted in residual anhydride which could evolve from the material. For such materials, a slightly epoxy-rich formulation is required to ensure that the material contains no residual unreacted anhydride. Analysis of volatiles generated by thermal exposure is an attractive characterization approach enabling compositional analysis as well as complementary diagnostics for materials degradation. Elsevier Ltd. 2020 Polymer Degradation and Stability 174 109032 10.1016/j.polymdegradstab.2019.109032 2020-02-24 OPUS4-51672 misc Braun, Ulrike; Eisentraut, Paul; Altmann, Korinna; Kittner, Maria; Dümichen, Erik; Thaxton, K.; Kleine-Benne, E.; Anumol, T. Accelerated Determination of Microplastics in Environmental Samples Using Thermal Extraction Desorption-Gas Chromatography/Mass Spectrometry (TED-GC/MS) There is growing interest in quantifying microplastics in environmental samples. This application note presents a thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS) method that is well suited to automation and increased sample throughput. The method is also able to detect all particle sizes in the sample as long as the limit of detection (LOD) is reached and allows analysis of larger samples of 15 to 25 mg or more. Samples were decomposed by thermogravimetric analysis (TGA), and the gaseous decomposition products were trapped on a solid-phase sorbent, followed by thermal desorption‑gas chromatography/mass spectrometry (TD-GC/MS) using an Agilent 5977B GC/MSD coupled to an Agilent 7890B GC. Target microplastic particle (MP) polymers were identified in environmental samples including surface water, finished compost, house dust, and drinking water. Quantification of MP polymers in environmental samples provided LODs of 0.06 to 2.2 μg, allowing the detection of MPs in trace amounts with sample weights of up to 1 g. Method repeatability was adequate for reliable quantification with RSDs of approximately 6 to 12%. USA Agilent Technologies Inc. 2020 Agilent Application Notes 2020 1 8 2020-11-30 OPUS4-40235 Zeitschriftenartikel Dümichen, Erik; Eisentraut, Paul; Bannick, Claus Gerhard; Barthel, Anne-Kathrin; Senz, R.; Braun, Ulrike Fast identification of microplastics in complex environmental samples by a thermal degradation method In order to determine the relevance of microplastic particles in various environmental media, comprehensive investigations are needed. However, no analytical method exists for fast identification and quantification. At present, optical spectroscopy methods like IR and RAMAN imaging are used. Due to their time consuming procedures and uncertain extrapolation, reliable monitoring is difficult. For analyzing polymers Py-GC-MS is a standard method. However, due to a limited sample amount of about 0.5 mg it is not suited for analysis of complex sample mixtures like environmental samples. Therefore, we developed a new thermoanalytical method as a first step for identifying microplastics in environmental samples. A sample amount of about 20 mg, which assures the homogeneity of the sample, is subjected to complete thermal decomposition. The specific degradation products of the respective polymer are adsorbed on a solid-Phase adsorber and subsequently analyzed by thermal Desorption gas chromatography mass spectrometry. For certain identification, the specific degradation products for the respective polymer were selected first. Afterwards real environmental samples from the aquatic (three different rivers) and the terrestrial (bio gas plant) systems were screened for microplastics. Mainly polypropylene (PP), polyethylene (PE) and polystyrene (PS) were identified for the samples from the bio gas plant and PE and PS from the rivers. However, this was only the first step and quantification measurements will follow. Elsevier 2017 Chemosphere 174 572 584 10.1016/j.chemosphere.2017.02.010 2017-05-15 OPUS4-46460 Zeitschriftenartikel Eisentraut, Paul; Dümichen, Erik; Ruhl, A.; Jekel, M.; Albrecht, M.; Gehde, M.; Braun, Ulrike Two Birds with One Stone-Fast and Simultaneous Analysis of Microplastics: Microparticles Derived from Thermoplastics and Tire Wear Analysis of microplastic particles (MP) in environmental samples needs sophisticated techniques and is time intensive due to sample preparation and detection. An alternative to the most common (micro ) spectroscopic techniques, FTIR or Raman spectroscopy, are the thermoanalytical methods, where specific decomposition products can be analyzed as marker compounds for different kind of plastics types and mass contents. Thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) allows the fast identification and quantification of MP in environmental samples without sample preparation. Whereas up to now only the analysis of thermoplastic polymers was realized, this is the first time that even the analysis of tire wear (TW) content in environmental samples is possible. Various marker compounds for TW were identified. They include characteristic decomposition products of elastomers, antioxidants and vulcanization agents. Advantages and drawbacks of these marker substances were evaluated. Environmental samples from street run off were exemplarily investigated and presented. American Chemical Society 2018 ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 5 10 608 613 10.1021/acs.estlett.8b00446 2018-11-05 OPUS4-41910 Vortrag Dümichen, Erik Thermal extraction/desorption-gas chromatography-mass spectroscopy: A powerful tool for analyzing the degradation and decomposition of polymers Due to the high molecular weights the analysis of polymers is difficult to carry out. Their dissolution is usually limited and the vapor pressure is very low. However, the degradation of a polymer leads usually to smaller compounds which then enable volatile analysis to aid in the characterization of the degradation or decomposition mechanism. The type and the amount of these smaller degradation products is characteristic for the momentary stage of the degradation process. With thermal desorption coupled to gas chromatography with mass spectrometry (TDS-GC-MS) the polymers can be heated from ambient temperatures to approximately 300 °C. During the heating process small volatile products with a molecular mass up to 350 - 400 m/z were first cryogenic trapping, reheated under controlled conditions and finally separated through a chromatographic column and identified with mass spectrometry. For instance clear differences in the released volatile species of Polypropylene (PP) can be observed depending on the progress of accelerated aging. In combination with a Thermogravimetric analyzer (TGA) the samples can be heated up to 1000 °C under inert as well oxidative atmosphere. This leads to a complete thermal-pyrolytic or thermo-oxidative degradation of the whole material and a release of degradation fragments over a range of Mw. These fragments enable conclusions for the underlying degradation or decomposition pathways. For coupling to GC-MS a solid-phase adsorption agent can be coupled to the exhaust of the TGA. This adsorption agent is usually a PDMS species that is capable to adsorb compounds with a wide range of polarities. After the thermal extraction the solid-phase adsorption agent will be analyzed by TDS-GC-MS. Therefore, it is possible to determine the species and amounts of the released complex thermal or thermo-oxidative degradation products in detail. This approach offers overall advantageous over existing volatile analytical methods. Thus, it was possible to determine new thermal and thermo-oxidative degradation mechanism pathways of a well-known material like Polyamide 66 (PA 66). Further example is the unique analysis of small polymer particles, which can be identified and quantified in complex environmental samples. This is our current focus of R&D activities within the framework of the analysis of microplastics in the environment. In the present work we will present a new, automatized set up of this method. 2017 PDDG Taormina, Sicily, Italy 04.09.2017 07.09.2017 2017-09-13 OPUS4-42143 Zeitschriftenartikel Dümichen, Erik; Eisentraut, Paul; Bannick, Claus Gerhard; Barthel, Anne-Kathrin; Braun, Ulrike; Senz, R. Fast identification of microplastics in complex environmental samples by a thermal degradation method n order to determine the relevance of microplastic particles in various environmental media, comprehensive investigations are needed. However, no analytical method exists for fast identification and quantification. At present, optical spectroscopy methods like IR and RAMAN imaging are used. Due to their time consuming procedures and uncertain extrapolation, reliable monitoring is difficult. For analyzing polymers Py-GC-MS is a standard method. However, due to a limited sample amount of about 0.5 mg it is not suited for analysis of complex sample mixtures like environmental samples. Therefore, we developed a new thermoanalytical method as a first step for identifying microplastics in environmental samples. A sample amount of about 20 mg, which assures the homogeneity of the sample, is subjected to complete thermal decomposition. The specific degradation products of the respective polymer are adsorbed on a solid-phase adsorber and subsequently analyzed by thermal desorption gas chromatography mass spectrometry. For certain identification, the specific degradation products for the respective polymer were selected first. Afterwards real environmental samples from the aquatic (three different rivers) and the terrestrial (bio gas plant) systems were screened for microplastics. Mainly polypropylene (PP), polyethylene (PE) and polystyrene (PS) were identified for the samples from the bio gas plant and PE and PS from the rivers. However, this was only the first step and quantification measurements will follow. Elsevier Ltd. 2017 Chemosphere 174 572 584 10.1016/j.chemosphere.2017.02.010 2017-09-26 OPUS4-42146 Zeitschriftenartikel Deußing, G.; Dümichen, Erik; Braun, Ulrike Polymeranalytik Intelligent kombiniert Durch die intelligente Anbindung an die Stir Bar Sorptive Extraction (SBSE) lassen sich Zersetzungsprodukte der thermogravimetrischen Analyse (TGA) von Polymeren auf effiziente Weise anreichern, auftrennen und mittels GC/MS identifizieren. Gerstel Gerstel 2016 Gerstel Aktuell 51 9 11 2017-09-26 OPUS4-42149 Zeitschriftenartikel Deußing, G.; Dümichen, Erik; Braun, Ulrike Der Fänger im Spülgas Durch die intelligente Anbindung an eine in der GC/MS gängige Extraktionstechnik (SBSE) lassen sich Zersetzungsprodukte der thermogravimetrischen Analyse (TGA) von Polymeren auf effiziente Weise anreichern, anschließend trennen und sicher identifizieren. Vogel Business Media 2015 Laborpraxis 39 6 24 27 2017-09-26 OPUS4-42170 Zeitschriftenartikel Dümichen, Erik; Eisentraut, Paul; Braun, Ulrike Polymere und Mikroplastik in der Umwelt Es wird ein neues und voll automatisiertes Verfahren vorgestellt für die Analyse von Mikroplastik in der Umwelt. Wiley 2017 GIT Labor-Fachzeitschrift 61 9 24 27 2017-09-26 OPUS4-42171 Dissertation Dümichen, Erik Einsatz neuer thermoanalytischer Verfahren zur Untersuchung thermischer und thermo-oxidativer Degradationsmechanismen sowie dem Netzwerkaufbau von Polymeren Die Anwendung thermoanalytischer Methoden für die Polymercharakterisierung hat aufgrund der makromolekularen Struktur von Polymere Vorteile. Es wurden zwei neue thermoanalyti-sche Verfahren entwickelt und deren Einsatz anhand von Anendungsbeispielen demons-triert, sowie mit etablierten, thermoanalytischen Methoden verglichen. Für die thermische- und thermo-oxidative Zersetzungsgasanalytik wurde die Thermogravi-metrie (TGA) gekoppelt mit der Thermodesoptions-Gaschromatographie-Massenspektrometrie (TDS-GC-MS). Die Zersetzungsgase der TGA wurden dafür über ei-nen Festphasenadsorber geleitet, auf dem eine repräsentative Auswahl von polymerspezifi-schen Analyten adsorbiert wurde. Die thermische Extraktion der Analyten erfolgte in der TDS-GC-MS. Dies ermöglichte die Trennung der Analyten sowie die eindeutige Identifizie-rung mittels charakteristischer Massenfragmentmuster. Sie wurde als TED-GC-MS bezeichnet. Es stellte sich heraus, dass sie sich besonders für die Analyse von komplexen Kohlen-wasserstoffgemischen mit Molmassen von mehr als 100 g/mol eignet. In Kombination mit anderen Kopplungstechniken wie beispielsweise die TGA-FTIR/MS, die speziell für die Ana-lyse von kleineren Molekülen verwendet wurde, konnten neue grundlegende Zersetzungs-mechanismen entwickelt werden. Es wurde beispielsweise sichtbar, dass sowohl bei der thermischen als auch bei der thermo-oxidativen Degradation von Polyamid 66 (PA 66) Kon-densationsreaktionen eine wichtige Rolle spielen. Die Methode erwies sich darüber hinaus als besonders geeignet für die Identifizierung und Quantifizierung von Polymeren in Umweltproben. Es entstand dazu eine erste grundlegende Arbeit für die quantitative Bestimmung von Polyethylen (PE) Mikroplastik in Umweltproben. Im zweiten Teil der Arbeit wurde eine steuerbare beheizbare Zelle eingeführt. Mit ihr war es möglich, mit Hilfe der Nahinfrarotspektroskopie (NIR), sich verändernde Netzwerkstrukturen während der Härtung sichtbar zu machen. Vergleichend dazu wurden etablierte, kalorische Messungen durchgeführt. Somit konnten für verschiedene Epoxidsysteme die Aushärtegrade während der Härtung mit variablen Heizraten bestimmt werden. Dadurch konnten Aushär-tungskinetiken erstellt werden, die durch isotherme und komplexe Aushärtungsszenarien validiert wurden. Berlin FU Berlin 2016 1 65 urn:nbn:de:kobv:188-fudissthesis000000100982-9 http://creativecommons.org/licenses/by/3.0/de/deed.de 2017-09-27 OPUS4-42154 Vortrag Dümichen, Erik Neue Verfahren zur Untersuchung der Polymerdegradation und Aushärtung Es werden neue analytische Verfahren für die thermische und thermo-oxidative Degradation von Polymeren dargestellt sowie für die Analyse des Netzwerkaufbaus von Epoxidharzen. 2014 Hochschule Hamm-Lippstadt 16.12.2014 16.12.2014 2017-09-26 OPUS4-42157 Zeitschriftenartikel Elert, Anna Maria; Becker, Roland; Dümichen, Erik; Eisentraut, Paul; Falkenhagen, Jana; Sturm, Heinz; Braun, Ulrike Comparison of different methods for MP detection: What can we learn from them, and why asking the right question before measurments matters? In recent years, an increasing trend towards investigating and monitoring the contamination of the environment by microplastics (MP) (plastic pieces < 5 mm) has been observed worldwide. Nonetheless, a reliable methodology that would facilitate and automate the monitoring of MP is still lacking. With the goal of selecting practical and standardized methods, and considering the challenges in microplastics detection, we present here a critical evaluation of two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction with subsequent size exclusion chromatography (SEC) using a soil with known contents of PE, PP, PS and PET as reference material. The obtained results were compared in terms of measurement time, technique handling, detection limits and requirements for sample preparation. The results showed that in designing and selecting the right methodology, the scientific question that determines what needs to be understood is significant, and should be considered carefully prior to analysis. Depending on whether the object of interest is quantification of the MP particles in the sample, or merely a quick estimate of sample contamination with plastics, the appropriate method must be selected. To obtain overall information about MP in environmental samples, the combination of several parallel approaches should be considered. Elsevier 2017 Environmental Pollution 231 2 1256 1264 10.1016/j.envpol.2017.08.074 2017-09-26 OPUS4-42159 Vortrag Dümichen, Erik Neue Verfahren zur Untersuchung der Polymerdegradation und Aushärtung Es werden neue analytische Verfahren für die thermische und thermo-oxidative Degradation von Polymeren dargestellt sowie für die Analyse des Netzwerkaufbaus von Epoxidharzen. 2017 Sonderkolloquium des Adolf-Martens-Fonds e. V. Berlin, Germany 30.05.2017 30.05.2017 2017-09-26