TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - Polycondensations and Cyclization of Poly(L-lactide) Ethyl Esters in the Solid State N2 - The usefulness of seven different Tin catalysts, Bismuth subsalicylate and Titan tetra(ethoxide) for the polycondensation of ethyl L-lactate (ELA) was examined at 150 °C/6 d. Dibutyltin bis(phenoxides) proved to be particularly effective. Despite the low reactivity of ELA, weight average molecular masses (Mw) up to 12 500 were found along with partial crystallization. Furthermore, polylactides (PLAs) of similar molecular masses were prepared via ELA-initiated ROPs of L-lactide by means of the four most effective polycondensation catalysts. The crystalline linear PLAs were annealed at 140 or 160 °C in the presence of these catalysts. The consequences of the transesterification reactions in the solid PLAs were studied by means of matrix-assisted laser desorption/ionization (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC) and small-angle X-ray scattering (SAXS). The results indicate that polycondensation and formation of cycles proceed in the solid state via formation of loops on the surface of the crystallites. In summary, five different transesterification reactions are required to explain all results. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592934 DO - https://doi.org/10.1039/d3py01232h SN - 1759-9962 VL - 15 IS - 2 SP - 71 EP - 82 PB - RSC Publ. CY - Cambridge AN - OPUS4-59293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna A1 - Bannick, C. G. A1 - Kerndorff, A. A1 - Heller, C. A1 - Fuchs, M. A1 - Braun, U. T1 - Welche Rolle spielen Textilien als Mikroplastik-Quelle im Abwasser? Was kann man dagegen tun? N2 - Diskutiert wird die Frage, ob Textilien gewaschen in der Waschmaschine ein Eintragspfad von Mikroplastik in die Umwelt sind. Nachgewiesen wird dies experimentell über Messungen zur Massenbestimmung mit der TED-GC/MS. T2 - DWA-Seminar: Mikroplastik in der (Siedlungs-)Wasserwirtschaft – Einordnung und Handlungsempfehlungen für die Praxis CY - Online meeting DA - 29.11.2023 KW - Mikroplastik KW - TED-GC/MS KW - Waschmaschine KW - Polymer 3R PY - 2023 AN - OPUS4-59279 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna A1 - Bannick, C. G. A1 - Kerndorff, A. A1 - Heller, C. A1 - Fuchs, M. A1 - Braun, U. T1 - Welche Rolle spielen Textilien als Mikroplastik-Quelle im Abwasser? N2 - In diesem Vortrag wird die Rolle der Waschmaschine als Eintragspfad von Mikroplastik in das Abwasser diskutiert und eine experimentelle Annäherung an das Problem beschrieben. T2 - Wasserwirtschaftliches Kolloquium der TU Berlin CY - Berlin, Germany DA - 14.12.2023 KW - Mikroplastik KW - TED-GC/MS KW - Waschmaschine PY - 2023 AN - OPUS4-59278 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lisec, Jan A1 - Recknagel, Sebastian A1 - Prinz, Carsten A1 - Vogel, Kristin A1 - Koch, Matthias A1 - Becker, Roland T1 - eCerto—versatile software for interlaboratory data evaluation and documentation during reference material production N2 - The statistical tool eCerto was developed for the evaluation of measurement data to assign property values and associated uncertainties of reference materials. The analysis is based on collaborative studies of expert laboratories and was implemented using the R software environment. Emphasis was put on comparability of eCerto with SoftCRM, a statistical tool based on the certification strategy of the former Community Bureau of Reference. Additionally, special attention was directed towards easy usability from data collection through processing, archiving, and reporting. While the effects of outlier removal can be flexibly explored, eCerto always retains the original data set and any manipulation such as outlier removal is (graphically and tabularly) documented adequately in the report. As a major reference materials producer, the Bundesanstalt für Materialforschung und -prüfung (BAM) developed and will maintain a tool to meet the needs of modern data processing, documentation requirements, and emerging fields of RM activity. The main features of eCerto are discussed using previously certified reference materials. KW - Reference material KW - Statistics KW - Software KW - Collaborative trial PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591851 DO - https://doi.org/10.1007/s00216-023-05099-3 SP - 1 EP - 9 PB - Springer Science and Business Media LLC AN - OPUS4-59185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz A1 - Karafiludis, Stephanos A1 - Pimentel, C. A1 - Montes Hernandez, G A1 - Kochovski, Z A1 - Bienert, Ralf A1 - Weimann, Karin A1 - Emmerling, Franziska A1 - Scoppola, E A1 - Van Driessche, A T1 - Solution-driven processing of calcium sulfate: the mechanism of the reversible transformation of gypsum to bassanite in brines N2 - Calcium sulfate hemihydrate (CaSO4ᐧ0.5H2O), also known as bassanite, has been used as a precursor to produce gypsum (dihydrate, CaSO4ᐧ2H2O) for various construction and decorative purposes since prehistoric times. The main route to obtain hemihydrate is a thermal treatment of gypsum at temperatures typically between 150 °C and 200 °C to remove some of the structural water. In this contribution, we introduce (Fig. 1) a more efficient and sustainable method (T < 100 °C) that enables the direct, rapid, and reversibly conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brines with c[NaCl] > 4 M). The optimum conditions for the efficientproduction of bassanite in a short time (< 5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the typical behaviour of the bassanite phase in low salt environments. Traditionally, hemihydrate is obtained through a solid state thermal treatment because bassanite is considered to be metastable with respect to gypsum and anhydrite in aqueous solutions, and therefore gypsum-to-bassanite conversion should not occur in water. Its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures is inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline structure for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. T2 - Granada Münster Discussion Meeting GMDM 10 CY - Münster, Germany DA - 29.11.2023 KW - Gypsum KW - Bassanite KW - Calcium sulfate KW - Recycling KW - Scattering PY - 2024 AN - OPUS4-59162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karafiludis, Stephanos A1 - Kochovski, Z. A1 - Scoppola, E. A1 - Retzmann, Anika A1 - Hodoroaba, Vasile-Dan A1 - ten Elshof, J. E. A1 - Emmerling, Franziska A1 - Stawski, Tomasz Maciej T1 - Nonclassical Crystallization Pathway of Transition Metal Phosphate Compounds N2 - Here, we elucidate nonclassical multistep crystallization pathways of transition metal phosphates from aqueous solutions. We followed precipitation processes of M-struvites, NH4MPO4·6H2O, and M-phosphate octahydrates, M3(PO4)2·8H2O, where M = Ni, Co, or NixCo1–x, by using in situ scattering and spectroscopy-based techniques, supported by elemental mass spectrometry analyses and advanced electron microscopy. Ni and Co phosphates crystallize via intermediate colloidal amorphous nanophases, which change their complex structures while agglomerating, condensing, and densifying throughout the extended reaction times. We reconstructed the three-dimensional morphology of these precursors by employing cryo-electron tomography (cryo-ET). We found that the complex interplay between metastable amorphous colloids and protocrystalline units determines the reaction pathways. Ultimately, the same crystalline structure, such as struvite, is formed. However, the multistep process stages vary in complexity and can last from a few minutes to several hours depending on the selected transition metal(s), their concentration, and the Ni/Co ratio. KW - Non-classical crystallization theory KW - Transition metals KW - Phosphates KW - Amorphous phases KW - Intermediate phases PY - 2023 DO - https://doi.org/10.1021/acs.chemmater.3c02346 SN - 1520-5002 VL - 35 IS - 24 SP - 10645 EP - 10657 PB - American Chemical Society (ACS) CY - Washington D.C. AN - OPUS4-59135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habibimarkani, Heydar A1 - John, Elisabeth A1 - Schusterbauer, Robert A1 - Abram, Sarah-Luise A1 - Prinz, Carsten A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Complementary Characterization of FeNi-Oxide Nanoparticles as Catalysts for Water Electrolysis combining Electron Microscopy, EDS, XRD, ToF-SIMS and Electrochemical Analysis N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research. A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling. The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible. The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential. T2 - SIMS Europe 2023 CY - Nottingham, England DA - 02.09.2023 KW - FeNi-Oxide NPs KW - ToF-SIMS KW - Catalysts KW - OER PY - 2023 AN - OPUS4-59143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Giovannozzi, A. A1 - Rossi, A. A1 - Kovac, J. A1 - Ekar, J. A1 - Goenaga-Infante, H. A1 - Clarkson, C. A1 - Clifford, C. A1 - Cant, D. A1 - Minelli, C. A1 - Reithofer, M. A1 - Lindner, G. A1 - Venzago, C. A1 - Bohmer, N. A1 - Drexler, C.-P. A1 - Schedler, U. A1 - Thiele, T. A1 - Lechart, F. A1 - Kästner, B. A1 - Sjövall, P. A1 - Johnston, L. A1 - Tan, Gunnar A1 - Radnik, Jörg T1 - Standardised Measurements of Surface Functionalities on Nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods. T2 - European Partnership on Metrology 2023 Review Conference CY - Amsterdam, Netherlands DA - 07.11.2023 KW - Surface chemistry KW - Quality assurance KW - Traceability PY - 2023 AN - OPUS4-59142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habibimarkani, Heydar A1 - John, Elisabeth A1 - Schusterbauer, Robert A1 - Abram, Sarah-Luise A1 - Prinz, Carsten A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan A1 - Radnik, Jörg T1 - Investigating the Synergistic Effects of FeNi-Oxide Nanoparticles as Water Electrolysis Catalysts: A Multi-Technique Characterization Approach N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research. A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling. The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible. The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential. T2 - European Materials Research Society (E-MRS) Fall 2023 CY - Warsaw, Poland DA - 18.09.2023 KW - FeNi-Oxide NPs KW - ToF-SIMS KW - Catalysts KW - OER PY - 2023 AN - OPUS4-59139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Prinz, Carsten A1 - Zimathies, Annett A1 - Emmerling, Franziska T1 - Experimantal raw data sets associated with certified reference material BAM-P116 (titanium dioxide) for comparison of nitrogen and argon sorption, available in the universal adsorption information format (AIF) N2 - These data sets serve as models for calculating the specific surface area (BET method) using gas sorption in accordance with ISO 9277. The present measurements were carried out with nitrogen at 77 Kelvin and argon at 87 Kelvin. It is recommended to use the following requirements for the molecular cross-sectional area: Nitrogen: 0.1620 nm² Argon: 0.1420 nm² Titanium dioxides certified with nitrogen sorption and additionally measured with argon for research purposes were used as sample material. The resulting data sets are intended to serve as comparative data for own measurements and show the differences in sorption behaviour and evaluations between nitrogen and argon. These data are stored in the universal AIF format (adsorption information file), which allows flexible use of the data. KW - Physisorption KW - Surface area KW - AIF KW - Argon KW - Nitrogen PY - 2023 DO - https://doi.org/10.5281/zenodo.10199628 PB - Zenodo CY - Geneva AN - OPUS4-59102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -