TY - JOUR A1 - Jaunich, Matthias T1 - The average number of references per article published in Polymer Testing over the years N2 - This Editorial is focussed on the changes in the number of references per article published in Polymer Testing from 1980 until today. To set in into context with other changes a comparison with the impact factor of Polymer Testing is presented. KW - Reference KW - Editorial KW - Impact factor KW - Changes with time PY - 2018 U6 - https://doi.org/10.1016/j.polymertesting.2018.05.034 SN - 0142-9418 VL - 68 SP - A1 EP - A2 PB - Elsevier AN - OPUS4-45212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Investigation of the low-temperature performance of rubber seals N2 - For many sealing applications rubbers are applied due to their special material properties and easy use. In many applications as e.g. in aviation, traffic or process technology the material can be exposed to low temperatures during operation. Therefore, it is important to know the material behaviour at those low temperatures to determine the temperature range that allows a safe operation of the seal. In this work, we focus on the behaviour of elastomer seals at low temperatures with regard to potential decrease of leak-tightness or catastrophic seal failure of O-ring rubber seals. This is required as material properties of rubbers are strongly temperature dependent but their temperature application range is not always clearly defined. Based on previous investigations which considered the physical material properties and the seal behaviour under purely static conditions we widen the focus on the sealing performance after a fast partial relief of compressed seals and additional materials. For the investigations, different typical rubber seal materials were used as e.g. fluorocarbon (FKM), ethylene propylene diene (EPDM) and hydrogenated acrylonitrile-butadiene (HNBR) rubber. The correlation of the physical material properties with seal performance is studied. This includes as well purely static sealing applications as the performance during/after fast partial relief of seals at low temperatures. T2 - Polymertec 2018 CY - Merseburg, Germany DA - 13.06.2018 KW - Seal KW - Low temperature KW - Leakage PY - 2018 AN - OPUS4-45214 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Dichtungsverhalten bei niedrigen Temperaturen - Untersuchung der unteren Temperatureinsatzgrenze N2 - Elastomere werden vielfach in Produkten eingesetzt, die bei verschiedenen Temperaturen verwendet werden. Dabei sind O-Ringe kostengünstige Dichtelemente, die allerdings für die Funktionsfähigkeit und Sicherheit eines Produkts entscheidend sind. Die untere Temperatureinsatzgrenze ist dabei durchaus relevant und aus wissenschaftlicher Sicht nicht allgemeingültig zu definieren, da diese einerseits durch die Änderungen der Materialeigenschaften im Zuge des Gummi-Glas-Übergangs definiert werden, die Temperaturlage dieses Übergangs jedoch sehr stark von den jeweiligen Einsatzbedingungen (z.B. Frequenz) abhängt. Dadurch ergeben sich große Unterschiede zwischen statischen und dynamischen Anwendungen. Verschiedene Untersuchungen sollen vorgestellt und interpretiert werden, um das Auditorium auf verschiedene Herausforderungen aufmerksam zu machen und Lösungsansätze vorzustellen... T2 - ISGATEC O-Ring Forum CY - Mannheim, Germany DA - 20.06.2018 KW - Dichtung KW - Glasübergang KW - O-Ring KW - Druckverformungsrest KW - Leckagerate PY - 2018 AN - OPUS4-45299 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trajkovski, B. A1 - Jaunich, Matthias A1 - Müller, W. A1 - Beuer, F. A1 - Zafiropoulos, G. A1 - Houshmand, A. ED - Eppel, S.J. T1 - Hydrophilicity, viscoelastic, and physicochemical properties variations in dental bone grafting substitutes N2 - The indication-oriented Dental Bone Graft Substitutes (DBGS) selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties’ influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA) of xenograft (cerabone®), synthetic (maxresorb®), and allograft (maxgraft®, Puros®) blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone® and maxresorb® blocks showed a slight height decrease in wet state, whereas both maxgraft® and Puros® had an almost identical height increase. In addition, cerabone® and maxresorb® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft® and Puros® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone®, Bio-Oss®, NuOss®, SIC® nature graft) and synthetic DBGS granules (maxresorb®, BoneCeramic®, NanoBone®, Ceros®). The highest level of hydrophilicity was detected in cerabone® and maxresorb®, while Bio-Oss® and BoneCeramic® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this study initiates a new insight into the DBGS differences and their importance for successful clinical results. KW - Biomaterials KW - Bone grafting KW - Bone substitutes KW - Hydrophilicity KW - Mechanical analysis PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-439890 SN - 1996-1944 VL - 11 IS - 2 SP - Article 215, 1 EP - 19 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-43989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Kömmling, Anja A1 - Wolff, Dietmar A1 - Jaunich, Matthias ED - van Breugel, K. ED - Koleva, D. ED - Beek, T. T1 - Investigation of long-term behaviour of elastomeric seals for transport and storage packages N2 - Elastomers are widely used as the main sealing materials in Containers for low- and intermediate-level radioactive waste and as an additional component fo metal seals in spent-fuel and high-level waste containers. According to appropriate guidelines and regulations, safe enclosure of the radioactive container contents has to be guaranteed for lengthy storage periods of at least 40 years. Therefore, the understanding of seal ageing behaviour is of high importance and has to be considered with regard to possible dynamic events taking place during transport after storage. An accelerated ageing approach for compressed seals is presented, as well as some first results. KW - O Ring KW - Ageing KW - Rubber seal PY - 2018 SN - 978-3-319-70192-9 U6 - https://doi.org/10.1007/978-3-319-70194-3_2 SP - 17 EP - 25 PB - Springer AN - OPUS4-43248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Skrotzki, Birgit A1 - Wolff, Dietmar T1 - Creep investigations on aluminum seals for application in radioactive waste containers N2 - In Germany spent nuclear fuel and high level radioactive waste is stored in interim storage containers with double lid systems. Those lids are equipped with metal seals (e.g. Helicoflex®) that ensure the safe enclosure of the inventory. The used metal seals consist of three components as can be seen in the cross-sectional view in Figure 1. The innermost part is a helical spring that is surrounded by an inner jacket made of stainless steel. The outer jacket that is made of a softer material which in case of assembly in the aforementioned storage containers is silver or aluminum (i.e. Al 99.5). During application the seal is compressed and due to the restoring force of the helical spring, the outer jacket is plastically deformed and adapts to the sealing surface. Hence, leakage paths are closed and the sealing function is generated. In Germany the above-mentioned containers are licensed for up to 40 years of interim storage, which in case extended storage becomes necessary before a final repository is available will have to be extended to even longer periods. Therefore, the evaluation of the long-term behavior of the seals is necessary, taking into account storage conditions, decay heat and possible mechanical loads as well. At Bundesanstalt für Materialforschung und –prüfung (BAM) long-term investigations are being conducted in which seals are assembled in test flanges and aged at temperatures ranging from room temperature to 150°C for accelerated aging. The aged seals are tested semi-annually (after the first 6 months in which the seals are tested more frequently) regarding the sealing performance, the remaining seal force, and the useable resilience upon decompression. Results of these investigations have been published over the past years (e.g. Grelle, Wolff, Probst, Jaunich, & Völzke, 2017; Völzke, Wolff, Probst, Nagelschmidt, & Schulz, 2014). It was found that the seal force and the useable resilience decrease with time and temperature, which is in agreement with the result of other studies (Sassoulas et al., 2006; Wataru et al., 2016) as well. Geometry change of the outer jacket has been identified as the main reason for this seal behavior. At the prevailing operating temperatures and stresses the aluminum is subjected to creep deformation leading to a thinning of the outer jacket. Since the seal groove depth remains unchanged the helical spring expands, which in turn leads to a decrease of the generated spring and seal force. Although the main reason for the change of seal parameters over time and temperature is known, a detailed characterization of the seal behavior and a reliable prediction of the parameter development for aging times that exceed the experimental time frame have not been possible, yet. For deeper understanding of the aging processes, an Investigation program, which is covered in this contribution, is conducted at Bundesanstalt für Materialforschung und –prüfung (BAM) that focusses on the behavior of the aluminum jacket and its influence on the long-term sealing performance. The program investigates properties of material samples as well as the behavior of the seal as a component. Original sheet material of the same aluminum that is used for manufacturing of the seals is investigated in compression creep tests. For this, a DMA (dynamic mechanical analysis) machine is employed (here used for static tests) that allows for a measurement of the specimens deformation under forces of up to 500 N. The advantage of this method is that the original material can be tested in the same shape as used for the seals which is 0.5 mm thick sheet material. For investigation of tensile creep standard specimens are used, that were machined from surrogate material of the same composition and annealing condition. Furthermore, aluminum seals that are cut into smaller segments are assembled in flanges and placed in heating chambers at temperatures ranging from 23°C to 150°C. After different periods of time from 3 days to 300 days the segments are taken out of the flanges and are investigated, thus giving information on different states of aging. Measurements of the development of the seal contact width and the aluminum jacket thickness are done with an optical microscope. Further investigations on the segments will include metallography and hardness measurements. From the detailed material and component behavior including the results of the long-term seal force and useable resilience investigations a better understanding of the overall seal behavior can be gained. The aim is to contribute to the development of material models and analytical approaches for the prediction of the sealing behavior in dependence of time and temperature. T2 - International Conference on Aluminum Alloys CY - Montreal, Canada DA - 17.06.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SN - 978-1-926872-41-4 SP - 1 EP - 2 AN - OPUS4-45844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Arfi, W. A1 - Khan, A. A1 - Moulai, F. A1 - Agroui, K. A1 - Baretta, C. A1 - Oreski, G. A1 - Jaunich, Matthias ED - Munday, J. ED - Bermel, P. ED - Kempe, M. T1 - Optical and thermal analysis of PVB encapsulant polymer functionalized with luminescent organic dyes N2 - This work focused on the technology of luminescent down shift (LDS), with a primary aim to identify and investigate a methodology to introduce the luminescent organic dye into PVB polymer encapsulant as emergent material for photovoltaic application. For this goal, we propose to study the feasibility to implement the LDS functionality and to identify suitability of available luminescent to be incorporated into the host polymer encapsulant material. The first step to this direction was through a comprehensive optical study of Violet 570 (V) organic dye in ethanol solvent. The methodology and experimental conditions such as laboratory polymer preparation and luminescence dye concentration were presented. Also, the emergent polymer encapsulant sheets were characterized by using optical and thermal analysis techniques. The absorption spectrum of the prepared PVB material shifts towards longer wavelengths, with increasing organic dye concentration. T2 - New Concepts in Solar and Thermal Radiation Conversion and Reliability CY - San Diego, California, United States DA - 19.08.2018 KW - Photovoltaic KW - Encapsulation KW - Luminescence PY - 2018 SN - 9781510620902 U6 - https://doi.org/10.1117/12.2318428 SN - 1996-756X SP - Paper OH, 1 PB - SPIE CY - Bellingham, Washington, USA AN - OPUS4-47165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Jaunich, Matthias T1 - Effect of high-dose gamma irradiation on (U)HMWPE neutron shielding materials N2 - High and ultra-high molecular weight polyethylenes were gamma-irradiated with doses up to 600 kGy. The changes in the material properties were analysed using DSC, DMA, IR spectroscopy, as well as measurements of density and insoluble content. The irradiation led to an increase of the degree of crystallinity because of chain scissions during irradiation, leading to shorter and thus more mobile chains. Both the plateau value of the shear modulus G′ and the insoluble content increased with Irradiation dose, indicating the formation of additional crosslinks. Furthermore, IR spectroscopy revealed irradiation induced oxidation and the formation of double bonds, indicating that some of the hydrogen atoms responsible for the neutron shielding capability have been released. KW - Ultra high molecular weight KW - Polyethylene KW - Gamma irradiation KW - Crosslinking KW - Oxidation PY - 2018 U6 - https://doi.org/10.1016/j.radphyschem.2017.02.014 SN - 0969-806X VL - 142 SP - 29 EP - 33 PB - Elsevier AN - OPUS4-42941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Goral, Milan A1 - Grelle, Tobias A1 - Wolff, Dietmar T1 - Low temperature performance of rubber seals - Influence of crystallite formation on seal performance N2 - Rubbers are widely used as sealing materials in various applications. In many fields the function of seal materials at low temperatures is necessary. Therefore, the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that rubbers possess strongly temperature dependent material properties. At low temperatures high changes in the material properties are observed which can be caused by the rubber-glass transition (abbr. glass transition) or for some rubbers also by partial crystallisation at lower temperatures. During continuous cooling the material changes during rubber-glass transition from rubber-like entropy-elastic behaviour to stiff energy-elastic behaviour. In case of (thermal-) crystallisation the formed crystallites act as additional (physical) crosslinks within the material but the molecules in the amorphous phase can still behave like a rubber. Hence, rubbers are normally used above rubber-glass transition and (thermal-) crystallization temperature but the minimum working temperature limit is heavily depending on the application conditions. Therefore, the lower operation temperature limit of rubber seals is under investigation. In the past we have investigated material properties and sealing behaviour of rubber seals at low temperatures. As the initial work was dedicated to purely static sealing conditions we started to investigate the effect of a small partial release of rubber seals at low temperatures to study the influence of dynamic events on leak tightness. In addition, other groups report on the influence of counterpart surface and adhesion. In this contribution we focus on the difference between purely amorphous elastomers and elastomers which become partially crystalline at low temperatures. The influence of partial crystallization on the low temperature performance of rubber seals is discussed. T2 - Fall Rubber Colloquium 2018 CY - Hannover, Germany DA - 06.11.2018 KW - Seal KW - Low temperature KW - Rubber KW - Partial crystalline PY - 2018 AN - OPUS4-46553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Investigation of the time and temperature dependent behavior of metal seals in radioactive waste containers N2 - The Bundesanstalt für Materialforschung und –Prüfung (BAM) runs an investigation program on the long-term behavior of multi-component metal seals. Such seals are used in a wide area of applications including transport and storage casks for spent nuclear fuel and high level radioactive waste. The seal function is mainly based on the compression of the inner helical spring, which generates the necessary seal force to keep the sealing surfaces in close contact. This in turn leads to a plastic deformation of the outer jacket of the seal, comprised of highly ductile aluminum or silver that adapts to the sealing surfaces of cask body and bolted lid, thus providing high Level leak tightness. In Germany, those casks are licensed for Interim storage periods of up to 40 years or more if extended Interim storage would become necessary before a final repository is available. Thus, the sealing performance has to be evaluated, including factors like elevated temperature due to decay heat or mechanical loads due to transport under normal as well as accident conditions. Long-term investigations at BAM have been running over the last nine years to identify and evaluate the seal performance by measuring the remaining seal force, the useable resilience and the leakage rate after various time intervals at temperatures ranging from room temperature up to 150 °C. It was found that the seal force and useable resilience decrease with time and temperature, caused by creep deformation of the outer jacket. In order to obtain an analytical description for the seal behavior and to achieve more information on the material behavior under application conditions a comprehensive investigation program with Focus on aluminum as outer jacket material was launched. The program includes material investigations such as compression and tension creep tests with representative basic materials. An additional test setup allows for the continuous measurement of the remaining seal force at temperatures of up to 150 °C. Furthermore, seal segments are compressed and stored in heating chambers, thus producing segments at different stages of the aging process. The segments are investigated regarding the development of the contact area width, jacket thickness and microstructural changes. This data will be used to develop material models and an analytical description of the time and temperature dependent long-term sealing behavior. This paper explains the current status of gained test results and modelling approaches and closes with an outlook to the future Project plans. T2 - ASME 2018 Pressure Vessels and Piping Conference CY - Prague, Czech Republic DA - 15.07.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SP - PVP2018-84584, 1 EP - 6 AN - OPUS4-46110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -