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 DO - 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 - CONF A1 - Stark, Wolfgang T1 - Einsatz thermoanalytischer Methoden bei der Charakterisierung vernetzender Kunststoffe T2 - Anwenderseminar zur Thermoanalyse, Netzsch, Analytica 2012 CY - Munich, Germany DA - 2012-04-18 PY - 2012 AN - OPUS4-25890 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - Investigation of Crosslinking and degradation process by infrared Spectroscopy T2 - 4th bilateral Symposium on heterocyclic and heterochain polymers for advanced materials CY - Iasi, Romania DA - 2012-09-03 PY - 2012 AN - OPUS4-26493 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - BAM - Federal Institute for Materials Research and Testing - experiences in the field of quality management at thermosets T2 - 4th Bilaterial Symposium on heterocyclic and heterochain polymers for advanced materials CY - Iasi, Romania DA - 2012-09-03 PY - 2012 AN - OPUS4-26518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - Thermoanalytische Methoden DSC/Hochdruck-DSC und DMA bei der Charakterisierung der Vernetzung reaktiver Kunststoffe T2 - Praxistag Uni Rostock "Thermische Analyse für spezielle Anwendungen" CY - Rostock, Germany DA - 2012-06-19 PY - 2012 AN - OPUS4-26084 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - Characterization of thermosetting polymers for manufacturing of composite parts by thermal analysis methods T2 - 4th bilateral Symposium on heterocyclic and heterochain polymers for advanced materials CY - Iasi, Romania DA - 2012-09-03 PY - 2012 AN - OPUS4-26492 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stark, Wolfgang A1 - Jaunich, Matthias A1 - Bohmeyer, W. A1 - Lange, K. T1 - Investigation of the crosslinking behaviour of ehtylene vinyl acetate (EVA) for solar cell encapsulation by rheology and ultrasound N2 - EVA is a widely used material for the encapsulation of photovoltaic modules. It melts at elevated temperatures, and seals the module before it is crosslinked at temperatures above 130 °C by a peroxide-initiated crosslinking reaction. EVA has good optical properties necessary for application in solar modules. For process optimization and quality management, a method for the quick and reliable characterization of EVA crosslinking behaviour is of great value. Here, the practicability of ultrasound for online crosslinking monitoring is demonstrated. A sound velocity increase of about 8 m/s during the crosslinking reaction is found. The ultrasound results are compared with rheometer measurements performed with a curemeter typically used for the investigation of rubber crosslinking. KW - Ethylene vinyl acetate KW - EVA KW - Crosslinking KW - Ultrasound KW - Rheology KW - Curemeter KW - DSC PY - 2012 DO - https://doi.org/10.1016/j.polymertesting.2012.07.004 SN - 0142-9418 VL - 31 IS - 7 SP - 904 EP - 908 PB - Elsevier CY - Amsterdam AN - OPUS4-26291 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stark, Wolfgang T1 - Correlation between low temperature behaviour of rubber seals and glass-rubber transition T2 - 4th Bilateral Symposium on heterocyclic and heterochain polymers for advanced materials CY - Iasi, Romania DA - 2012-09-03 PY - 2012 AN - OPUS4-26519 LA - deu 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 DO - 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 - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang T1 - Low temperature properties of rubber seals - results of component tests N2 - Rubbers are widely used as sealing material in various applications. In many fields the function of seal materials at low temperatures is required. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. Therefore the lower operation temperature limit of rubber seals should be determined in dependence of the material properties. The results of Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) are combined with results of standardized measurements as the compression set according to ISO 815. To reduce the test time of the standard tests a faster and more efficient technique was developed and applied. In addition the breakdown temperature of the sealing function of O-ring seals at low temperatures is measured in a component test setup in dependence of the material and the degree of compression. T2 - 10th Fall rubber colloquium CY - Hannover, Germany DA - 07.11.2012 PY - 2012 SN - 978-3-9814076-1-7 IS - khk2012_jaunich.pdf SP - 1 EP - 8 AN - OPUS4-26995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Low temperature - For a seal this depends on the applied material T1 - Tieftemperatur - Bei Dichtungen entscheidet dies der eingesetzte Werkstoff 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 behavior at those low temperatures to determine the temperature ränge that allows a safe Operation of the seal. One of our main Interests is to ensure the safe enclosureof dangerous goods under various conditions such as different temperatures and over long periods of time. For low temperatures the seal function of an elastomer is limited 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, as the glass-rubber transition covers a broad temperatureregion and is strongly influenced by the applied loading frequency. Therefore the applicability of a seal material has to be assessed by its properties in relation to the application conditions and the necessary level of tightness. To characterize the material and the seal function thermal analysis (Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA)), a modlfied method for the accelerated determination of compression set and component tests were applied to different rubber classes, The results show that the temperature ränge where the compression set values come close to 100 % correlates well with the onset temperature of the storage modulus measured by DMA ata measurement frequency of 1 Hz. An in depth analysis of the compression set data allows an estimation of the expected time- and temperature-dependent recovery behavior. T2 - DKT 2012 - German Rubber Conference CY - Nuremberg, Germany DA - 02.07.2012 PY - 2012 IS - 10-2330_5-L-1530 SP - 1 EP - 4 PB - Deutsche Kautschuk-Gesellschaft CY - Frankfurt am Main AN - OPUS4-26190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Material behaviour of static seals at low temperatures N2 - For many sealing applications rubber materials are applied due to their Special material properties and easy use. The crucial advantage of elastomeric seals in comparison to other seal is their high resilience. 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 behavior at those low temperatures to determine the temperature ränge that allows a safe Operation of the seal. For low temperatures the seal function of an elastomer is in a way limited by the rubber-glass transition during which the material properties change from rubber-like to stiff and glass-like. This may result in a direct loss of the sealing function but especially for purely static applications a leak tightness well below the rubber-glass transition was observed, For a given application this correlation is not trivial, as the glass-rubber transition covers a broad temperature region and is strongly influenced by the applied load period. Therefore the applicability of a seal material has to be assessed by its properties in relation to the application conditions and the -ecessary level of tightness. T2 - 17th ISC - International sealing conference CY - Stuttgart, Germany DA - 13.09.2012 PY - 2012 SN - 978-3-00-039198-9 IS - A 16 SP - 295 EP - 300 CY - Frankfurt/M. AN - OPUS4-26524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -