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Die Erwartungen der Prozessindustrie an die NAMUR Open Architecture sind groß, schließlich soll das Konzept der Garant für die digitale Transformation der Branche sein. Im atp-Interview warnt Dr. Michael Maiwald, Fachbereichsleiter „Prozessanalytik“ an der Bundesanstalt für Materialforschung und -prüfung (BAM), allerdings davor, NOA als Allheilmittel zu betrachten.
The heterogeneous mesostructure of concreted causes local stress concentrations. Stress dependent phenomena like damage and creep as well as their interactions are effected by those stress
concentrations. Therefore a material model’s macroscopic behavior will differ whether the mesoscale structure is considered or not. The differences between the mesoscale approach and an homogeneous approach will be presented. The results are discussed with focus on the true materials behavior.
The interest in repair technologies for polymer composites has increased significantly over the last decades, due to the growing use of these materials in structural applications. In this study, poly (ethylene-co-methacrylic acid) (EMAA) was used as self-healing agent to glass fiber/epoxy composite. Materials with EMAA contents of 2 wt% and 5 wt% were manufactured using Resin Transfer Molding (RTM) and the effects of the healing agent on the properties were investigated using tensile tests and Dynamic Mechanical Analysis (DMA). Results show slight variation of properties, which was more pronounced as the content of EMAA increased. In addition, the healing efficiency was investigated through fatigue tests and the addition of higher content of EMAA increased the number of cycles to failure after the healing activation cycle.
Large-language models (LLMs) such as GPT-4 caught the interest of many scientists. Recent studies suggested that these models could be useful in chemistry and materials science. To explore these possibilities, we organized a hackathon. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines.
We report the selective ring opening copolymerisation (ROCOP) of
oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K
catalyst precisely yielding semi-crystalline alternating poly(esteralt-
thioesters) which show improved degradability due to the
thioester links in the polymer backbone.
Scientific publications addressing the durability of the flame retardance of cables during their long-term application are rare and our understanding lacks. Three commercial flame retardants, aluminum hydroxide, aluminum diethyl phosphinate (AlPi-Et), and intumescent flame retardant based on ammonium polyphosphate, applied in ethylene-vinyl acetate copolymer (EVA) model cables, are investigated. Different artificial aging scenarios were applied: accelerated weathering (UV-irradiation/temperature/rain phases), humidity exposure (elevated temperature/humidity), and salt spray exposure. The deterioration of cables’ surface and flame retardancy were monitored through imaging, color measurements, attenuated total reflectance Fourier transform infrared spectroscopy, and cone calorimeter investigations. Significant degradation of the materials’ surface occurred. The flame retardant EVA cables are most sensitive to humidity exposure; the cable with AlPi-Et is the most sensitive to the artificial aging scenarios. Nevertheless, substantial flame retardance persisted after being subjected for 2000 h, which indicates that the equivalent influence of natural exposure is limited for several years, but less so for long-term use.
The durability of flame retardancy is a challenge for cables over long lifetimes. The degradation of flame retardance is investigated in two kinds of exposures, artificial weathering and humidity. In this basic study, typical mineral flame retardants in two polymers frequently used in cable jackets are investigated to get the fundamental picture. Aluminum hydroxide (ATH) and magnesium hydroxide (MDH) are compared in ethylene‐vinyl acetate (EVA), and further in EVA and linear low‐density polyethylene (LLDPE) cables containing the same ATH. The changes in chemical structure at the surface are studied through attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), the formation of cracks, and changes in color are investigated. The cone calorimeter and a bench scale fire testing cable module are utilized to evaluate the fire behavior of the cables. Although the flame retardancy deteriorated slightly, it survived harsh exposure conditions for 2000 h. Compared to EVA/MDH and LLDPE/ATH, the fire behavior of EVA/ATH is the least sensitive. Taken together, all of the results converge to estimate that there will be no problem with flame retardancy performance, for materials subjected to natural exposure for several years; the durability of fire retardancy is questionable for longer periods, and thus requires further investigation.
Mit einer langfristigen Forschungsstrategie begleiten die für die Sicherheit von Mensch und Umwelt zuständigen Bundesoberbehörden (Umweltbundesamt, Bundesinstitut für Risikobe-wertung, Bundesanstalt für Arbeitsschutz und Arbeitsmedizin, Bundesanstalt für Materialfor-schung und -prüfung und Physikalisch-Technische Bundesanstalt) die rasch voranschreiten-de Entwicklung neuer Materialien unter den Gesichtspunkten des Arbeits-, Verbraucher- und Umweltschutzes. Die Strategie steht daher in enger Verbindung zu den öffentlichen Förder-programmen für Nanomaterialien und andere innovative Werkstoffe, z. B. des BMBF („Vom Material zur Innovation“) und der EU („Horizon 2020“).
Die Forschungsstrategie baut auf den bisherigen Ergebnissen der 2008 begonnenen und 2013 erstmals bilanzierten gemeinsamen Forschungsstrategie der Bundesoberbehörden „Nanotechnologie - Gesundheits- und Umweltrisiken von Nanomaterialien"1 auf und erweitert den Blickwinkel auch auf andere Materialinnovationen, bei denen vergleichbare Risiken für Mensch und Umwelt bestehen oder abgeklärt werden müssen. Darüber hinaus greift sie die Idee „anwendungssichere chemische Produkte“2 aus der Initiative „Neue Qualität der Arbeit“ (INQA) des Bundesministeriums für Arbeit und Soziales (BMAS) und das Konzept der nach-haltigen Chemie3 auf, das vom Bundesministerium für Umwelt, Naturschutz, Bau und Reak-torsicherheit (BMUB) unterstützt wird. Durch eine anwendungssichere und umweltverträgli-che Gestaltung innovativer Materialien und ihrer Folgeprodukte sollen nicht akzeptable Risi-ken für Mensch und Umwelt von Anfang an weitgehend ausgeschlossen werden. Dies kann erreicht werden durch
1.
die Verwendung sicherer Materialien ohne Gefahreneigenschaften für Mensch und Umwelt (direkte Anwendungssicherheit) oder
2.
eine Produktgestaltung, die über den gesamten Lebenszyklus emissionsarm und umweltverträglich ist (integrierte Anwendungssicherheit) oder
3.
eine Unterstützung des Anwenders (product stewardship) durch den Hersteller bei technischen, organisatorischen und persönlichen Schutzmaßnahmen zur sicheren Verwendung und Entsorgung des Produktes (unterstützte Anwendungssicherheit).
Die Fortschreibung der Forschungsstrategie soll als Bestandteil des Nanoaktionsplans 2020 der Bundesregierung Beiträge der Ressortforschung zu folgenden Schwerpunkten leisten:
•
Charakterisierung und Bewertung der Risiken von Materialinnovationen
•
Unterstützung von Forschungseinrichtungen und Unternehmen
•
Fortschreiben von Rechtsvorschriften und Praxisempfehlungen
1
http://www.baua.de/nn_47716/de/Themen-von-A-Z/Gefahrstoffe/Nanotechnologie/pdf/Forschungsstrategie.pdf
2 http://www.baua.de/de/Themen-von-A-Z/Gefahrstoffe/Nachhaltige-Chemie/Nachhaltige-Chemie.html
3
http://www.umweltbundesamt.de/themen/chemikalien/chemikalien-management/nachhaltige-chemie
2
•
Gesellschaftliche Akzeptanz
Die Forschungsstrategie soll mit Projekten und anderen forschungsnahen Aktivitäten umge-setzt werden. Dies umfasst die eigene Forschung der Häuser, die extramurale Ausschrei-bung und Vergabe von Forschungsdienstleistungen sowie die Beteiligung an vorwiegend öffentlich geförderten Drittmittelprojekten. Hinzu kommen Aktivitäten im Rahmen der Politik-beratung und der hoheitlichen Aufgaben. Mit inter- und transdisziplinären Ansätzen soll die Risiko- und Sicherheitsforschung enger mit der Innovationsforschung und Materialentwick-lung verknüpft werden. Die Forschungsstrategie ist aufgrund der raschen Entwicklungen auf diesem Gebiet für den Zeitraum bis 2020 angelegt. Die Forschungsziele adressieren die in diesem Zeitraum voraussichtlich umsetzbaren Forschungsansätze. Die Forschungsstrategie wird durch einen Arbeitskreis begleitet und spätestens mit Ablauf des Nanoaktionsplans 2020 evaluiert und angepasst.
Fire stability of glass-fibre sandwich panels: The influence of core materials and flame retardants
(2017)
Fire resistance has become a key property for structural lightweight sandwich components in aviation, shipping, railway vehicles, and construction. The development of future composite materials and components demands adequate test procedures for simultaneous application of compression and fully developed fire. Therefore an intermediate-scale approach (specimen size = 500 mm x 500 mm) is applied with compressive loads (up to 1 MN) and direct application of a burner to one side of the specimens, as established in aviation for severe burn-through tests. The influence of different core structures (polyvinylchloride foam, polyisocyanorate foam reinforced by stitched glass bridges, and balsa wood) was investigated for glass-fibre-reinforced sandwich specimens with and without flame retardants applied on the fabrics, in the matrix, and on surface for each specimen at the same time. Times to failure were increased up to a factor of 4. The intumescent coating prolongs the time to failure significantly.
What is more, using the intrinsic potential of the front skin together with the core to protect a load bearing back skin in sandwich panels, the design of the core – here using the wood core – is the most promising approach.
Concrete structures experience severe damage during service, for example due to pitting corrosion of rebars caused by the ingress of chlorine (Cl) into the porous concrete structure. The ingress can be monitored using laser-induced breakdown spectroscopy (LIBS), a recently introduced civil engineering technique used to detect Cl in concrete structures in addition to conventional wet chemistry methods. The key advantages of LIBS are high spatial resolution, which is important when analyzing heterogeneous concrete samples, as well as the almost complete absence of sample preparation. To assess LIBS as a reliable analytical method, its accuracy and robustness must be carefully tested. This paper presents the results of an interlaboratory comparison on the analysis of Cl in cement paste samples conducted by 12 laboratories in 10 countries. Two sets of samples were prepared with Cl content ranging from 0.06 to 1.95 wt% in the training set and 0.23–1.51 wt% in the test set, with additional variations in the type of cement and Cl source (salt type). The overall result shows that LIBS is suitable for the quantification of the studied samples: the average relative error was generally below 15%. The results demonstrate the true status quo of the LIBS method for this type of analysis, given that the laboratories were not instructed on how to perform the analysis or how to process the data.