TY - JOUR A1 - Dümichen, Erik A1 - Braun, Ulrike A1 - Senz, R. A1 - Fabian, G. A1 - Sturm, Heinz T1 - Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry N2 - For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA–FTIR) and mass spectrometry (TGA–MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS–GC–MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA–FTIR and TGA–MS. KW - TDS-GC-MS KW - TGA-FTIR KW - TGA-MS KW - Degradation KW - Polymer KW - Solid-phase extraction PY - 2014 U6 - https://doi.org/10.1016/j.chroma.2014.05.057 SN - 0021-9673 VL - 1354 SP - 117 EP - 128 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-31046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grabmayer, K. A1 - Wallner, G.M. A1 - Beißmann, S. A1 - Braun, Ulrike A1 - Steffen, R. A1 - Nitsche, D. A1 - Röder, B. A1 - Buchberger, W. A1 - Lang, R.W. T1 - Accelerated aging of polyethylene materials at high oxygen pressure characterized by photoluminescence spectroscopy and established aging characterization methods N2 - Two commercial polyethylene grades were exposed to water at elevated temperatures and enhanced oxygen pressure. To characterize their aging behavior laser-induced photoluminescence spectroscopy was applied. Additionally, aging characterization was performed by established methods such as tensile testing, infrared (IR) spectroscopy, high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC) and UV–VIS spectroscopy. During the initial stages of aging, the overall concentration of phenolic antioxidants as well as oxidation onset temperatures decreased exponentially. Simultaneously, significant discoloration due to the formation of conjugated degradation products from phenolic antioxidants (e.g., quinone methides) was detected. After the consumption of antioxidants, photoluminescence started to grow continuously presumably due to the formation of photoluminescent unsaturated carbonyls. In the final stages of aging, embrittlement of the materials as characterized by the degradation of mechanical properties (i.e., loss in ductility) coincided with rising carbonyl index values as well as an increase in crystallinity due to chemicrystallization. Between integrated photoluminescence intensity and carbonyl index, a linear correlation was established. In the induction period, the photoluminescence method exhibited a significantly higher sensitivity to reflect aging induced material changes. KW - Polyethylene KW - PE-RT KW - High oxygen pressure KW - Photoluminescence spectroscopy KW - Aging PY - 2014 U6 - https://doi.org/10.1016/j.polymdegradstab.2014.06.021 SN - 0141-3910 SN - 1873-2321 VL - 109 SP - 40 EP - 49 PB - Applied Science Publ. CY - London AN - OPUS4-31349 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -