TY - CONF A1 - Hennersdorf, Felix A1 - Weltschev, Margit A1 - Hertwig, Andreas T1 - ATR Investigations into the effect of ageing on HD-PE heating oil storage tanks after a service life of more than 30 years N2 - Heating oil storage tanks made of polyethylene grades have been on the market in Germany since the early 1970s. To ensure safety, their replacement is recommended by tank manufacturers after a period of 30 years. Polyethylene is subject to ageing by alteration of the properties during its life cycle. The degree of degradation and the nature of the process mainly depend on the chemical alteration of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no data available on the long-term behaviour of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was to find a suitable test method to determine the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s. Therefore, tank sections from the bottom, the shell and the roof of 22 individual storage tanks produced of polyethylene grades A and B have been examined by Melt Flow Rate (MFR) and Attenuated Total Reflectance (ATR). Their service life was in the range between 20 and 41 years. The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). An increase of the MFR was determined for the samples of polyethylene grade A, whereas a reduction of the MFR values was measured for most samples of polyethylene grade B. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer. ATR analysis exhibits an absorption band at 909 cm‒1 predominantly in samples of polyethylene grade A indicating chain scission and concomitantly formed terminal vinyl groups. This absorption band can be used for the characterization of the ageing of the polyethylene grades. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Heating oil tanks KW - Polyethylene KW - Ageing KW - Service life PY - 2019 AN - OPUS4-49000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Chatzigiannakis, Emmanouil A1 - Wachtendorf, Volker A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Discoloration effects of high-dose γ-irradiation and long-term thermal ageing of (U)HMW-PE N2 - Two polyethylene types with ultra high (UHMWPE) and high molecular weight (HMWPE), which are used as neutron radiation shielding materials in storage casks for radioactive waste, were subjected to gamma irradiation doses up to 600 kGy and subsequent thermal ageing at 125 °C for up to one year. One material was a medical grade UHMWPE and the other a HMWPE containing an antioxidant. Degradation effects in the materials were characterized using colorimetry, UV-Vis spectroscopy, MIR and FTIR measurements, DSC and, in the case of HMWPE, insoluble content determination. Both materials exhibited a yellowing upon irradiation. The discoloration of UHMWPE disappeared again after thermal ageing, which is why it was attributed to annealable color centers in the form of free radicals entrapped in the crystalline regions of the polymer that recombine during thermal ageing. Furthermore, oxidation species were observed with MIR and FTIR spectroscopy. For HMWPE, the yellowing occurred during both irradiation and thermal ageing and was correlated to antioxidant decomposition. Additionally, black spots were observed after thermal ageing of HMWPE that were attributed to reaction products of antioxidant derivatives and catalyst residues. While only little evidence of oxidation species was found in the light material parts, oxidation is expected to concentrate in the black spots as the catalyst residue promotes hydroperoxide decomposition and thus radical formation that initiate polymer oxidation T2 - Ionizing Radiation and Polymers Conference CY - Giens, France DA - 25.09.2016 KW - Polyethylene KW - Gamma-irradiation KW - Yellowing KW - Degradation PY - 2016 AN - OPUS4-38001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ciornii, Dmitri A1 - Hodoroaba, Vasile-Dan A1 - Benismail, Nizar A1 - Altmann, Korinna T1 - Interlaboratory comparisons for obtaining reliable data on microplastic detection methods N2 - Since microplastics (MPs) can be found everywhere and are becoming a problem of high concern, it is necessary to understand their occurrence and fate in the environment. However, to obtain data of high quality is very challenging, since measurement operating procedures differ from laboratory to laboratory. Currently, there are no standardized methods to analyze microplastics. One promissing possibility to adress standardization of the methodology and operating procedures are interlaboratory comparisons (ILCs). In this contribution we report the first results of an ILC on microplastic detection methods organized under the pre-stantdardisation plattform of VAMAS (www.vamas.org/twa45/) as Project 2 “Development of standardized methodologies for characterisation of microplastics with microscopy and spectroscopy methods”, within the Technical Working Area TWA 45 “Micro and Nano Plastics in the Environment”. The ILC has gathered 84 participants all over the world representing all continents. BAM, as the project leader, produced a set of reference microplastic materials, which have been distributed to all the participants together with the measurement protocols and reporting data templates. T2 - SETAC 34th Meeting CY - Seville, Spain DA - 05.05.2024 KW - ILC KW - Microplastic KW - Py-GC/MS KW - Polyethylene KW - µ-Raman KW - µ-FTIR KW - Polyethylene Terephtalate KW - TED-GC/MS PY - 2024 AN - OPUS4-60038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Hoffmann, Gabi A1 - Rehfeldt, Rainer A1 - Kohl, Anka T1 - Investigations on the degree of damage of polyethylene grades as materials of heating oil storage tanks after a service life of more than 30 years N2 - Tanks for heating oil made of polyethylene grades have been on the market since the early 1970s in Germany. Tank manufacturers recommend the replacement of the tanks after a period of 30 years due to guarantee safety. Polyethylene grades are subject to ageing by alteration of the properties during their life cycle. The degree of ageing and the nature of the degradation process mainly depend on the chemical degradation of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no results available on the long-term behavior of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was the determination of the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s. The determination of the Melt Flow Rate (MFR) and the Fourier Transmission IR Spectroscopy (FTIR) of tank sections from the bottom, the shell and the roof of 10 segregated heating oil storage tanks produced of polyethylene grades A and B were used as tests methods. The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). A reduction of the MFR values was measured for most of the sections of tanks made of polyethylene grade B after a service life of the tanks of more than 30 years. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer, and to a lesser extent by oxidative degradation. The FTIR analysis, especially of tank sections of the bottom and the shell showed that the intensity of the CH2 asymmetric and symmetric stretching vibrations in the range: 2800 - 2900 cm-1 and the CH2 bending deformation vibration at 1400 cm-1 increased due chain scissions. The intensity of the carbonyl stretching vibration C=O at 1740 cm-1 is low. The carbonyl index characterizes the degree of oxidation. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - Heating oil storage tanks KW - Polyethylene KW - Degree of damage KW - Melt Flow Rate (MFR) KW - FTIR PY - 2018 AN - OPUS4-45939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -