TY - JOUR A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - A new method to evaluate the low temperature function of rubber sealing materials N2 - A new method for the evaluation of the low temperature properties of rubber materials is presented. The method emulates the standardized compression set measurement, which is frequently used for sealing materials, but can be performed within a considerably shorter time. The results are compared with the standard test and found to be qualitatively the same. Slight differences are discussed on the basis of the differences in the measurement procedures. Further data evaluation is done by fitting functions to describe the material behaviour. KW - Sealing material KW - Elastomer KW - Compression set KW - Dynamic mechanical analysis KW - Low temperature behaviour PY - 2010 U6 - https://doi.org/10.1016/j.polymertesting.2010.07.006 SN - 0142-9418 VL - 29 IS - 7 SP - 815 EP - 823 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-21914 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Buchholz, Uwe A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Habel, Wolfgang A1 - Petersson, B.A.T. T1 - Acoustic data of cross linked polyethylene (XLPE) and cured liquid silicone rubber (LSR) by means of ultrasonic and low frequency DMTA N2 - Partial discharges may cause damage to electrical insulation of high voltage equipment. They initiate elastic waves in the insulating material, e.g. in the stress cone of an outdoor termination. Localisation of the origin of such elastic waves can help to predict serious damaging processes in the electrical insulation. In order to measure and evaluate the wave propagation effects in typical multilayered elastomeric structures, knowledge of the material properties is required. The propagating velocity and the attenuation of longitudinal waves are important parameters. Values for these quantities found in the literature were not appropriate. Therefore, for cross-linked polyethylene (XLPE) and cured liquid silicone rubber (LSR), the longitudinal wave velocity and the attenuation were evaluated in the temperature interval from -20°C to 50°C and in the frequency range from 200 kHz to 600 kHz using a two-sample ultrasound technique. The loss factor was determined from these measured quantities. Additionally, low frequency Dynamic Mechanical Thermal Analysis (DMTA) was applied to investigate LSR and XLPE in a temperature interval between -100 and 50°C and to check qualitatively the ultrasound data. KW - Acoustic propagation KW - Cross linked polyethylene insulation KW - Mechanical variables measurement KW - Silicone rubber PY - 2012 U6 - https://doi.org/10.1109/TDEI.2012.6180250 SN - 1070-9878 SN - 0018-9367 SN - 1558-4135 VL - 19 IS - 2 SP - 558 EP - 566 PB - Institute of Electrical and Electronics Engineers CY - New York, NY AN - OPUS4-26106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero A1 - Stark, Wolfgang T1 - Adhesion of amorphous polymers as a function of temperature probed with AFM force-distance curves N2 - Force–displacement curves have been obtained with a commercial atomic force microscope at different temperatures and probe rates on a thick film of poly(n-butyl methacrylate) and on two films of polystyrene with different molecular weight. In a previous publication [B. Cappella, S.K. Kaliappan, H. Sturm, Macromolecules 38 (2005)1874] the analysis of force–displacement curves has been focused on the stiffness and on the Young's modulus of the samples. In the present publication we consider the temperature dependence of the work of adhesion. We have obtained master curves of the work of adhesion at fixed maximum loads and, by comparing the results of the two analysis, we show that the work of adhesion follows the Williams–Landel–Ferry equation with the same coefficients previously found for the Young's modulus. Furthermore, we show that the temperature dependence of the work of adhesion of the polymers is a consequence of the temperature dependence of the tip–sample contact area and in the end of the temperature dependence of the stiffness and of the elastic–plastic properties of the samples. KW - Atomic force microscope KW - Force-distance curves KW - Indentation KW - Elastic-plastic properties KW - Adhesion KW - Time-temperature superposition principle KW - Glass transition temperature PY - 2005 U6 - https://doi.org/10.1016/j.jcis.2005.09.043 SN - 0021-9797 SN - 1095-7103 SP - 1 EP - 8(?) PB - Elsevier CY - Orlando, Fla. AN - OPUS4-11187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Behaviour of rubber seals at low temperatures - results of component tests - N2 - The investigation of low temperature properties of elastomeric sealing materials by means of thermo-analytical methods is a sound way to get information about the glass transition process. The breakdown temperature of the sealing function of O-ring seals was measured in a component test setup depending on material and degree of compression. An in depth explanation of the observed component tests behaviour is currently in preparation. It requires the results of thermo-analytical methods and measurements as the compression set (not shown here). With that, a model was developed to describe the correlation between physical material parameters and observed component behaviour. T2 - Jahrestagung Kerntechnik 2013 CY - Berlin, Germany DA - 14.05.2013 PY - 2013 SP - 1 EP - 6 AN - OPUS4-28574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stark, Wolfgang A1 - Jaunich, Matthias A1 - McHugh, J. T1 - Carbon-fibre epoxy prepreg (CFC) curing in an autoclave analogue process controlled by dynamic mechanical analysis (DMA) N2 - Carbon fibre prepregs have found widespread application in lightweight constructions. They are based on a carbon-fibre fabric impregnated with reactive epoxy resin. DMA measurements under temperature conditions similar to an autoclave programme were carried out using commercially available prepreg material with a high glass transition temperature. The characteristic of the temperature programme was a dynamic heating segment at 1.5 K/min followed by a longer isothermal segment at 180 °C. The courses of the storage modulus E', loss modulus E'' and tanδ were recorded. The measuring frequency was varied between 1 Hz and 33.3 Hz. Gelation and vitrification are assigned. The influence of the measuring frequency on the time to vitrification and the correlation with DSC are discussed. The reaction does not end even after 10 h curing at 180 °C, which is interpreted as the slow cessation of the reaction caused by vitrification. KW - Prepreg KW - CFC KW - Curing KW - DMA KW - DSC KW - Autoclave KW - Gelation KW - Vitrification KW - Glass transition PY - 2013 U6 - https://doi.org/10.1016/j.polymertesting.2013.09.014 SN - 0142-9418 VL - 32 IS - 8 SP - 1487 EP - 1494 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-29479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mc Hugh, Jarlath A1 - Döring, Joachim A1 - Stark, Wolfgang A1 - Erhard, Anton T1 - Characterisation of epoxy materials used in the development of ultrasound arrays T2 - 16th World Conference on Nondestructive Testing CY - Montreal, Canada DA - 2004-08-30 PY - 2004 UR - http://www.ndt.net/article/wcndt2004/pdf/materials_characterization/616_mchugh.pdf SP - 8 pages PB - International Committee for Non-Destructive Testing CY - Montreal AN - OPUS4-5215 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bovtun, Viktor Petrovic A1 - Stark, Wolfgang A1 - Kelm, Jürgen A1 - Pashkov, V.M. A1 - Yakimenko, Y. T1 - Characterization of carbon black filled rubber compounds by the Microwave Coaxial Method KW - Dielectric parameters KW - Microwave methods KW - Filled rubber compounds KW - Vulcanisation PY - 2005 SN - 0025-5300 VL - 47 IS - 3 SP - 118 EP - 122 PB - Carl Hanser Verlag CY - München AN - OPUS4-7273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Schulz, Sebastian A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Characterization of the low temperature behaviour of rubber sealing materials N2 - Rubbers are often used for seal applications due to their special material properties and easy use. In many applications the material is exposed to low temperatures during Operation. Therefore it is important to know the material behavior at low temperatures to determine the temperature ränge that allows a Safe Operation of the seal, e.g. in storage and transport Containers for radioactive materials. The seal function of an elastomer is limited in temperature by the rubber-glass transition during which the material properties change from rubber-like to stiff and glass-like. For a given application this correlation is not trivial and therefore needs an in-depth investigation under consideration of the physical properties and the application conditions. In this work different analytical methods are used to characterize the material behavior at low temperature in the ränge of the glass-rubber-transition and are compared with the quality of Operation of a component which is here defined by the detected leakage rate. T2 - Technomer 2011 - 22. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Deutschland DA - 10.11.2011 PY - 2011 SN - 978-3-939382-10-2 IS - Kap. 3.7 SP - 1 EP - 4 AN - OPUS4-24971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - Characterizing the flow-cure behaviour of thermoset plastics using thermoanalytical and ultrasonic methods N2 - The prospects of modern thermoanalytical methods for characterisation of flow, curing and final mechanical behaviour of moulding compounds were demonstrated. Using urea resin moulding compounds from different manufacturers the possibilities of the various techniques could be shown. With comparatively low effort, fundamental information can be gained before production process had been started. On this basis it is possible to make appropriate material selection at an early point in the process chain. On the basis of thermoanalytical data an incoming goods inspection can be established. Also it is easy to control the compliance with the conditions of delivery. In some cases it could also be helpful to have stored analysis data especially when problems appear in manufacturing process or unexpected part damages occur With the ultrasound measuring system it is possible to transfer the findings from the analytical methods directly to the processes in the mould. The application of ultrasound provides Dynamic Mechanical Analysis in the mould. Beside quality assurance ultrasound can also be used for process optimisation, especially for reduction of cycle time. In an advanced form ultrasound information can be used as a basis for improved machine control based on material state. The ultrasound measuring system developed by ISK Iserlohn and BAM can be obtained from the ISK. T2 - 5. Internationale Duroplasttagung / International Thermoset Conference CY - Iserlohn, Germany DA - 2008-11-20 KW - Differential Scanning Calorimetry KW - Dynamic Mechanical Analysis KW - Ultrasound KW - Urea rsin KW - Moulding compound KW - Incoming goods inspection KW - Process optimization PY - 2008 IS - Duro08_GB_08 SP - 1 EP - 8 AN - OPUS4-18586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Comparison of low temperature properties of different elastomer materials investigated by a new method for compression set measurement N2 - The method for the determination of compression set values with a Dynamic Mechanical Analysis (DMA) setup at low temperatures, which was presented previously, allows a much faster and readily automated procedure than the standardized compression set test according to ISO 815-2. This method is applied to a series of different elastomeric materials that are commonly used for sealing applications. The results of the compression set test are compared with results from thermal analysis to allow an in depth comparison of the material behaviour at low temperatures. Furthermore, a comparison between two EPDM materials is presented. These materials show very similar properties determined by thermo analytical methods such as Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) but differ clearly in their compression set behaviour. This comparison shows the importance and value of information of the compression set test in addition to thermal analysis to judge the behaviour of sealing materials and confirms the relevance of the new compression set test method for the investigation of low temperature properties of elastomers. KW - Sealing material KW - Elastomer KW - Compression set KW - Dynamic mechanical analysis KW - Low temperature behaviour PY - 2012 U6 - https://doi.org/10.1016/j.polymertesting.2012.07.016 SN - 0142-9418 VL - 31 IS - 8 SP - 987 EP - 992 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-26538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -