TY - RPRT A1 - Joschko, M. A1 - Reinhold, J. A1 - Barkusky, D. A1 - Wiemer, M. A1 - Remus, R. A1 - Busse, J. A1 - Müller, H.-J. A1 - Kiesel, J. A1 - Gleixner, G. A1 - Illerhaus, Bernhard A1 - Kirchner, M. A1 - Oehley, J. A1 - Gerlach, F. T1 - Wirkung einer organischen Düngung mit Seeschlamm auf sandigem Boden im nordostdeutschen Trockengebiet PY - 2009 SP - 1 EP - 162 CY - Frankfurt/Main AN - OPUS4-20928 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bungartz, M. A1 - Maenz, S. A1 - Kunisch, E. A1 - Horbert, V. A1 - Xin, L. A1 - Gunella, F. A1 - Mika, J. A1 - Borowski, J. A1 - Bischoff, S. A1 - Schubert, H. A1 - Sachse, A. A1 - Günster, Jens A1 - Illerhaus, Bernhard A1 - Bossert, J. A1 - Jandt, K. D. A1 - Kinne, R. W. A1 - Brinkmann, O. T1 - First-time systematic postoperative clinical assessment of a minimally invasive approach for lumbar ventrolateral vertebroplasty in the large animal model sheep N2 - Large animal models are highly recommended for meaningful preclinical studies, including the optimization of cement augmentation for vertebral body defects by vertebroplasty/kyphoplasty. The aim of this study was to perform a systematic characterization of a strictly minimally invasive in vivo large animal model for lumbar ventrolateral vertebroplasty. This is a prospective experimental animal study. Lumbar defects (diameter 5 mm; depth approximately 14 mm) were created by a ventrolateral percutaneous approach in aged, osteopenic, female sheep (40 Merino sheep; 6–9 years; 68–110 kg). L1 remained untouched, L2 was left with an empty defect, and L3 carried a defect injected with a brushite-forming calcium phosphate cement (CPC). Trauma/functional impairment, surgical techniques (including drill sleeve and working canula with stop), reproducibility, bone defects, cement filling, and functional cement augmentation were documented by intraoperative incision-to-suture time and X-ray, postoperative trauma/impairment scores, and ex vivo osteodensitometry, microcomputed tomography (CT), histology, static/fluorescence histomorphometry, and biomechanical testing. Minimally invasive vertebroplasty resulted in short operation times (28±2 minutes; mean±standard error of the mean) and X-ray exposure (1.59±0.12 minutes), very limited local trauma (score 0.00±0.00 at 24 hours), short postoperative recovery (2.95±0.29 hours), and rapid decrease of the postoperative impairment score to 0 (3.28±0.36 hours). Reproducible defect creation and cement filling were documented by intraoperative X-ray and ex vivo conventional/micro-CT. Vertebral cement augmentation and osteoconductivity of the CPC was verified by osteodensitometry (CPC>control), micro-CT (CPC>control and empty defect), histology/static histomorphometry (CPC>control and empty defect), fluorescence histomorphometry (CPC>control; all p<.05 for 3 and 9 months), and compressive strength measurements (CPC numerically higher than control; 102% for 3 months and 110% for 9 months). This first-time systematic clinical assessment of a minimally invasive, ventrolateral, lumbar vertebroplasty model in aged, osteopenic sheep resulted in short operation times, rapid postoperative recovery, and high experimental reproducibility. This model represents an optimal basis for standardized evaluation of future studies on vertebral augmentation with resorbable and osteoconductive CPC. KW - Computed tomography KW - Calcium phosphate cement KW - Large animal model KW - Minimal-invasive KW - Vertebroplasty KW - Void defect PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S152994301630273X U6 - https://doi.org/10.1016/j.spinee.2016.06.015 VL - 16 IS - 10 SP - 1263 EP - 1275 PB - Elsevier Inc. AN - OPUS4-38429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gunella, F. A1 - Kunisch, E. A1 - Maenz, S. A1 - Horbert, V. A1 - Xin, L. A1 - Mika, J. A1 - Borowski, J. A1 - Bischoff, S. A1 - Schubert, H. A1 - Sachse, A. A1 - Illerhaus, Bernhard A1 - Günster, Jens A1 - Bossert, J. A1 - Jandt, K. D. A1 - Plöger, F. A1 - Kinne, R. W. A1 - Brinkmann, O. A1 - Bungartz, M. ED - Carragee, T1 - The GDF5 mutant BB-1 enhances the bone formation induced by an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia N2 - BACKGROUND CONTEXT: Targeted delivery of osteoinductive bone morphogenetic Proteins (eg, GDF5) in bioresorbable calcium phosphate cement (CPC), potentially suitable for vertebroplasty and kyphoplasty of osteoporotic vertebral fractures, may be required to counteract augmented local bone catabolism and to support complete bone regeneration. The biologically optimized GDF5 Mutant BB-1 may represent an attractive drug candidate for this purpose. PURPOSE: The aim of the current study was to test an injectable, poly (l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming CPC containing low-dose BB-1 in a sheep lumbar osteopenia model. STUDY DESIGN/ SETTING: This is a prospective experimental animal study. METHODS: Bone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and were filled with fiber-reinforced CPC alone (L4; CPC+fibers) or with CPC containing different dosages. KW - Bone morphogenetic protein; KW - Bone regeneration; KW - Micro-Computed-Tomography; KW - Calcium phosphate cement; KW - GDF-5 mutant; KW - Large animal model sheep; KW - Osteoporotic vertebral fracture PY - 2018 U6 - https://doi.org/10.1016/j.spinee.2017.10.002 SN - 1529-9430 SN - 1878-1632 VL - 18 IS - 2 SP - 357 EP - 369 PB - Elsevier CY - New York AN - OPUS4-44561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gunella, F. A1 - Kunisch, E. A1 - Bungartz, M. A1 - Maenz, S. A1 - Horbert, V. A1 - Xin, L. A1 - Mika, J. A1 - Borowski, J. A1 - Bischoff, S. A1 - Schubert, H. A1 - Hortschansky, P. A1 - Sachse, A. A1 - Illerhaus, Bernhard A1 - Günster, Jens A1 - Bossert, J. A1 - Jandt, K. D. A1 - Plöger, F. A1 - Kinne, R. W. A1 - Brinkmann, O. T1 - Low-dose BMP-2 is sufficient to enhance the bone formation induced by an injectable, PLGA fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia N2 - BACKGROUND CONTEXT: Bioresorbable calcium phosphate cement (CPC) may be suitable for vertebroplasty/kyphoplasty of osteoporotic vertebral fractures. However, additional targeted de- livery of osteoinductive bone morphogenetic Proteins (BMPs) in the CPC may be required to counteract the augmented local bone catabolism and support complete bone regeneration. PURPOSE: This study aimed at testing an injectable, poly (l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement (CPC) containing low-dose bone morphogenetic Protein BMP-2 in a sheep lumbar osteopenia model. STUDY DESIGN/ SETTING: This is a prospective experimental animal study. METHODS: Bone defects (diameter 5 mm) were generated in aged, osteopenic female sheep and filled with fiber-reinforced CPC alone (L4; CPC+ fibers) or with CPC containing different dosages of BMP-2 (L5; CPC+ fibers + BMP-2; 1, 5, 100, and 500g BMP-2; n=5 or 6 each). The results were compared with those of untouched controls (L1). Three and 9 months after the operation, structural and functional effects of the CPC (±BMP-2) were analyzed ex vivo by measuring (1) bone Mineral density (BMD); (2) bone structure, that is, bone volume/total volume (assessed by micro-computed tomography [micro-CT] and histomorphometry), trabecular thickness, and trabecular number; (3) bone formation, that is, osteoid volume/bone volume, osteoid surface/bone surface, osteoid thickness, mineralizing surface/bone surface, mineral Apposition rate, and bone formation rate/bone surface; (4) bone resorption, that is, eroded surface/bone surface; and (5) compressive strength. RESULTS: Compared with untouched controls (L1), CPC+ fibers (L4) and/or CPC+ fibers + BMP-2(L5) significantly improved all parameters of bone formation, bone resorption, and bone structure. These effects were observed at 3 and 9 months, but were less pronounced for some parameters at 9 months. Compared with CPC without BMP-2, additional significant effects of BMP-2 were demonstrated for bone structure (bone volume/total volume, trabecular thickness, trabecular number) and formation (osteoid surface/bone surface and mineralizing surface/bone surface), as well as for the compressive strength. The BMP-2 effects on bone Formation at 3 and 9 months were dose-dependent, with 5–100g as the optimal dosage. CONCLUSIONS: BMP-2 significantly enhanced the bone formation induced by a PLGA fiber-reinforced CPC in sheep lumbar osteopenia. A single local dose as low as ≤100g BMP-2 was sufficient to augment middle to long-term bone formation. The novel CPC+ BMP-2 may thus represent an alternative to the bioinert, supraphysiologically stiff polymethylmethacrylate cement presently used to treat osteoporotic vertebral fractures by vertebroplasty/kyphoplasty. KW - Bone regeneration KW - Computed tomography KW - Calcium phosphat cement KW - Large animal model sheep KW - Osteoporotic vertebral fracture PY - 2017 U6 - https://doi.org/10.1016/j.spinee.2017.06.005 SN - 1529-9430 SN - 1878-1632 VL - 17 IS - 11 SP - 1699 EP - 1711 PB - Elsevier Inc. AN - OPUS4-43237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bungartz, M. A1 - Kunisch, E. A1 - Maenz, S. A1 - Horbert, V. A1 - Xin, L. A1 - Gunella, F. A1 - Mika, J. A1 - Borowski, J. A1 - Bischoff, S. A1 - Schubert, H. A1 - Sachse, A. A1 - Illerhaus, Bernhard A1 - Günster, Jens A1 - Bossert, J. A1 - Jandt, K. D. A1 - Plöger, F. A1 - Kinne, R. W. A1 - Brinkmann, O. T1 - GDF5 significantly augments the bone formation induced by an injectable, PLGA fiber-reinforced, brushite-forming cement in a sheep defect model of lumbar osteopenia N2 - BACKGROUND CONTEXT: Biodegradable calcium phosphate cement (CPC) represents a promising option for the surgical treatment of osteoporotic vertebral fractures. Because of augmented local bone catabolism, however, additional targeted delivery of bone morphogenetic proteins with the CPC may be needed to promote rapid and complete bone regeneration. PURPOSE: In the present study, an injectable, poly(l-lactide-co-glycolide) acid (PLGA) fiber-reinforced, brushite-forming cement (CPC) containing the bone morphogenetic Protein GDF5 was tested in a sheep lumbar osteopenia model. STUDY DESIGN/SETTING: This is a prospective experimental animal study METHODS: Defined bone defects (diameter 5 mm) were placed in aged, osteopenic female sheep. Defects were treated with fiber-reinforced CPC alone (L4; CPC+ fibers) or with CPC containing different dosages of GDF5 (L5; CPC+ fibers + GDF5; 1, 5, 100, and 500g GDF5; n = 5 or 6 each). The results were compared with those of untouched controls (L1). Three and 9 months postoperation, structural and functional effects of the CPC (±GDF5) were assessed ex vivo by measuring (1) bone mineral density (BMD); (2) bone structure, that is, bone volume/total volume (assessed by micro-computed tomography and histomorphometry), trabecular thickness, and trabecular number; (3) bone formation, that is, osteoid volume/bone volume, osteoid surface/bone surface, osteoid thickness, mineralized surface/bone surface, mineral apposition rate, and bone formation rate/bone surface; (4) bone resorption, that is, eroded surface/bone surface; and (5) compressive strength. RESULTS: Compared with untouched controls (L1), both CPC+ fibers (L4) and CPC+ fibers + GDF5 (L5) numerically or significantly improved all parameters of bone formation, bone resorption, and bone structure. These significant effects were observed both at 3 and 9 months, but for some parameters they were less pronounced at 9 months. Compared with CPC without GDF5, additional significant effects of CPC with GDF5 were demonstrated for BMD and parameters of bone formation and structure (bone volume/total volume, trabecular thickness, and trabecular number, as well as mineralized surface/bone surface). The GDF5 effects were dose-dependent (predominantly in the 5–100g range) at 3 and 9 months. CONCLUSIONS: GDF5 significantly enhanced the bone formation induced by a PLGA fiber-reinforced CPC in sheep lumbar osteopenia. The results indicated that a local dose as low as ≤100g GDF5 may be sufficient to augment middle to long-term bone formation. The novel CPC+ GDF5 combination may thus qualify as an alternative to the bioinert, supraphysiologically stiff poly-(methyl methacrylate) cement currently applied for vertebroplasty/kyphoplasty of osteoporotic vertebral fractures. KW - Bone regeneration KW - Computed tomography KW - Large animal model sheep KW - Osteoporotic vertebral fracture PY - 2017 U6 - https://doi.org/10.1016/j.spinee.2017.06.007 SN - 1529-9430 SN - 1878-1632 VL - 17 IS - 11 SP - 1685 EP - 1698 PB - Elsevier Inc. AN - OPUS4-43239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perret, Birgit A1 - Schartel, Bernhard A1 - Stöß, K. A1 - Ciesielski, M. A1 - Diederichs, J. A1 - Döring, M. A1 - Krämer, J. A1 - Altstädt, V. T1 - Novel DOPO-based flame retardants in high-performance carbon fibre epoxy composites for aviation N2 - Two novel, halogen-free, phosphorus-based oligomeric flame retardants are investigated in the commercial epoxy resin RTM6 and ~70 wt.% carbon fibre RTM6 composites (RTM6-CF) with respect to pyrolysis and fire behaviour. The flame retardants are based on 9,10-dihydro-9-oxy-10-phosphaphenanthrene-10-oxide (DOPO) units linked to the star-shaped aliphatic ground body tetra-[(acryloyloxy)ethyl] pentarythrit (DOPP), or heterocyclic tris-[(acryloyloxy)ethyl] isocyanurate (DOPI), respectively. The glass transition temperature is reduced by adding DOPP and DOPI, but the mechanical properties of the composites (e.g. interlaminar shear strength (ILSS) and Gc in mode I and II) remain unchanged. Decomposition models are proposed based on mass loss, evolved gas analysis (TG–FTIR) and condensed product analysis (hot stage cell within FTIR). The fire behaviour is investigated comprehensively (UL 94, limiting oxygen index (LOI) and cone calorimeter). Both flame retardants act in the gas phase through flame inhibition and in the condensed phase through charring. The UL 94 of RTM6 is improved from HB to V-1 and V-0; the LOI from 25% to 34–38%. Peak heat release rate (PHRR) and total heat evolved (THE) are lowered by 31-49% and 40–44%, respectively. Adding CF increases the residue, reduces the THE, but suppresses the charring due to RTM6 and flame retardants. Thus the THE of RTM6-CF is reduced by about 25% when DOPI and DOPP are added. However, UL 94: V-0 and LOI of 45% and 48% are achieved with ~0.6 wt.% phosphorus. KW - Epoxy resin (RTM6) KW - DOPO KW - Carbon fibre reinforced composites KW - Mechanical properties KW - Flame retardancy PY - 2011 U6 - https://doi.org/10.1016/j.eurpolymj.2011.02.008 SN - 0014-3057 SN - 1873-1945 VL - 47 IS - 5 SP - 1081 EP - 1089 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-23548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Perret, Birgit A1 - Schartel, Bernhard A1 - Stöß, K. A1 - Diederichs, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Krämer, J. A1 - Altstädt, V. ED - Lewin, M. T1 - Novel phosphorus-based flame retardants for epoxy resins and carbon fiber composites: Decomposition mechanisms and fire behavior T2 - 21st Annual conference on recent advances on flame retardancy of polymeric materials CY - Stamford, USA DA - 2010-05-24 KW - DOPO KW - Fire retardancy KW - Flammability KW - Pyrolysis KW - Epoxy resin KW - Composites PY - 2010 SN - 1-59623-619-1 VL - 21 SP - 134 EP - 145 PB - BCC Research AN - OPUS4-22162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perret, Birgit A1 - Schartel, Bernhard A1 - Stöß, K. A1 - Ciesielski, M. A1 - Diederichs, J. A1 - Döring, M. A1 - Krämer, J. A1 - Altstädt, V. T1 - A new halogen-free flame retardant based on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide for epoxy resins and their carbon fiber composites for the automotive and aviation industries N2 - The pyrolysis and fire behavior of halogen-free flame-retarded DGEBA/DMC, RTM6 and their corresponding 60 vol.-% carbon fibers (CF) composites were investigated. A novel phosphorous compound (DOPI) was used. Its action is dependent on the epoxy matrix. DGEBA/DMC and DOPI decompose independently of each other. Only flame inhibition occurs in the gas phase. RTM6 shows flame inhibition and a condensed phase interaction increasing charring. Both mechanisms decrease with increasing irradiance, whereas in RTM6-CF charring is suppressed at low ones. RTM6+DOPI shows a higher LOI (34.2%) than DGEBA/DMC+DOPI and a V-0 classification in UL 94. Adding CF only enhances the LOI, DOPI+CF leads to a superposition in LOI for DGEBA/DMC-CF+DOPI (31.8%, V-0) and a synergism for RTM6-CF+DOPI (47.7%, V-0). KW - Composites KW - Flame retardancy KW - Glass transition KW - Pyrolysis KW - Thermosets PY - 2011 U6 - https://doi.org/10.1002/mame.201000242 SN - 1438-7492 SN - 1439-2054 VL - 296 IS - 1 SP - 14 EP - 30 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xin, L. A1 - Bungartz, M. A1 - Maenz, S. A1 - Horbert, V. A1 - Hennig, M. A1 - Illerhaus, Bernhard A1 - Günster, Jens A1 - Bossert, J. A1 - Bischoff, S. A1 - Borowski, J. A1 - Schubert, H. A1 - Jandt, K. A1 - Kunisch, E. A1 - Kinne, R. A1 - Brinkmann, O. T1 - Decreased extrusion of calcium phosphate cement versus high viscosity PMMA cement into spongious bone marrow—an ex vivo and in vivo study in sheep vertebrae N2 - Vertebroplasty or kyphoplasty of osteoporotic vertebral fractures bears the risk of pulmonary cement embolism (3.5%–23%) caused by leakage of commonly applied acrylic polymethylmethacrylate (PMMA) cement to spongious bone marrow or outside of the vertebrae. Ultraviscous cement and specific augmentation systems have been developed to reduce such adverse effects. Rapidly setting, resorbable, physiological calcium phosphate cement (CPC) may also represent a suitable alternative. PURPOSE: This study aimed to compare the intravertebral extrusion of CPC and PMMA cement in an ex vivo and in vivo study in sheep. STUDY DESIGN/SETTING: A prospective experimental animal study was carried out. METHODS: Defects (diameter 5 mm; 15 mm depth) were created by a ventrolateral percutane-ous approach in lumbar vertebrae of female Merino sheep (2–4 years) either ex vivo (n = 17) or in vivo (n = 6), and injected with: (1) CPC (L3); (2) CPC reinforced with 10% poly(l-lactide-co-glycolide) (PLGA) fibers (L4); or (3) PMMA cement (L5; Kyphon HV-R). Controls were untouched (L1) or empty defects (L2). The effects of the cement injections were assessed in vivo by blood gas analysis and ex vivo by computed tomography (CT), micro-CT (voxel size: 67 µm), histology, and biomechanical testing. KW - Bone marrow extrusion KW - Brushite-forming calcium phosphate cement KW - Cement injection KW - Ex vivo KW - High- viscosity PMMA cement KW - In vivo KW - Large animal model KW - Sheep KW - Vertebroplasty PY - 2016 U6 - https://doi.org/10.1016/j.spinee.2016.07.529 SN - 1529-9430 SN - 1878-1632 VL - 16 IS - 12 SP - 1468 EP - 1477 PB - Elsevier Inc. AN - OPUS4-38058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernhard, J. A1 - Madia, Mauro A1 - Schork, B. A1 - Kucharczyk, P. A1 - Ngoula, D. A1 - Baumgartner, J. A1 - Schöne, Dieter T1 - Integrale bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen: Validierung an Stumpfstößen und Kreuzstößen N2 - In diesem Beitrag soll das Validierungskonzept der IBESS-Prozedur, sowie erste Ergebnisse und Erkenntnisse der noch gegenwärtig laufenden Validierung vorgestellt werden. Die Vorstellung erfolgt dabei am Beispiel der im Projekt eingesetzten geschweißten Stumpfstoß- sowie Kreuzstoßverbindung. Neben der Validierung des analytischen bruchmechanischen Modells zur Ermittlung der Schwingfestigkeit, steht auch die Validierung von Kriterien zur Interaktion und Koaleszenz von kurzen Mehrfachrissen im Fokus. T2 - DVS Congress 2015 - Große Schweißtechnische Tagung CY - Nuremberg, Germany DA - 14.09.2015 KW - Schwingfestigkeit KW - Bruchmechanik KW - IBESS PY - 2015 SN - 978-3-945023-46-4 N1 - Serientitel: DVS-Berichte – Series title: DVS-Berichte IS - 315 SP - 306 EP - 310 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-34797 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schork, B. A1 - Zerbst, Uwe A1 - Kucharczyk, P. A1 - Bernhard, J. A1 - Kaffenberger, M. A1 - Baumgartner, J. A1 - Oechsner, M. T1 - Imperfektionen für die schwingbruchmechanische Bewertung von Schweißverbindungen N2 - Bruchmechanischen Bewertungsmethoden liegt stets eine tatsachlich vorhandene oder fiktive Anfangsrisslange zu Grunde. Schweißverbindungen sind mit strukturellen Imperfektionen wie beispielsweise lnhomogenitaten in der Mikrostruktur und den Werkstoffeigenschaften behaftet, welche auf der Werkstoffseite berücksichtigt werden können. Imperfektionen wie der Kantenversatz und der Nahtübergangsradius, die als außere geometrische Imperfektionen aufgefasst werden können, haben vor allem Auswirkungen auf den Spannungszustand und werden daher auf der Lastseite erfasst. Innere geometrische Imperfektionen wie Einschlüsse oder Poren, von welchen Risse initiieren und sich ausbreiten, können als Ausgangsrissgröße aufgefasst werden. Im Teilprojekt A1 des Forschungsclusters IBESS wurden außere geometrische Imperfektionen an Schweißverbindungen ermittelt und statistisch ausgewertet. Des Weiteren wurden Schweißverbindungen fraktografisch im Rasterelektronenmikroskop (REM) bezüglich innerer geometrischer Imperfektionen untersucht, jedoch konnten aufgrund der hohen Schweißgütekeine schadigungsrelevanten inneren Imperfektionen (Ausgangsdefekte) detektiert werden. Um dennoch eine Ausgangsrisskonfiguration zu bestimmen, wurden "Heat-Tinting" Versuche eingesetzt, mit denen auf der Bruchflache verschiedene Anrissstadien markiert werden können. Mit dem .Heat-Tinting" Verfahren können sehr kleine Anrisse detektiert und in Abhangigkeit von der Beanspruchung frühe Anrisskonfigurationen ermittelt werden. Des Weiteren haben Zerbst und Madia im Teilprojekt A3 ein Modell entwickelt, mit dem für den Grundwerkstoff mittels zyklischer R-Kurven eine Ausgangsrissgröße rechnerisch ermittelt werden kann. Unter Verwendung der Ergebnisse aus den Versuchen zur Ermittlung der Anrissstadien soll dieses Modell validiert werden, um auch für Schweißverbindungen Anwendung zu finden. T2 - DVS Congress 2015 - Große Schweißtechnische Tagung CY - Nuremberg, Germany DA - 14.09.2015 KW - Schwingfestigkeit KW - Bruchmechanik KW - IBESS PY - 2015 SN - 978-3-945023-46-4 N1 - Serientitel: DVS-Berichte – Series title: DVS-Berichte IS - 315 SP - 271 EP - 277 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-34800 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xin, L. A1 - Mika, J. A1 - Horbert, V. A1 - Bischoff, S. A1 - Schubert, H. A1 - Borowski, J. A1 - Maenz, S. A1 - Huber, R. A1 - Sachse, A. A1 - Illerhaus, Bernhard A1 - Kinne, R. W. T1 - Systematic postoperative assessment of a minimally-invasive sheep model for the treatment of osteochondral defects N2 - To assess the clinical course of a sheep stifle joint model for osteochondral (OC) defects, medial femoral condyles (MFC) were exposed without patella luxation using medial parapatellar skin (3–4 cm) and deep incisions (2–3 cm). Two defects (7 mm diameter; 10 mm depth; OC punch) were left empty or refilled with osteochondral autologous transplantation cylinders (OATS) and explanted after six weeks. Incision-to-suture time, anesthesia time, and postoperative wound or impairment scores were compared to those in sham-operated animals. Implant performance was assessed by X-ray, micro-computed tomography, histology, and immunohistology (collagens 1, 2; aggrecan). There were no surgery-related infections or patellar luxations. Operation, anesthesia, and time to complete stand were short (0.5, 1.4, and 1.5 h, respectively). The wound trauma score was low (0.4 of maximally 4; day 7). Empty-defect and OATS animals reached an impairment score of 0 significantly later than sham animals (7.4 and 4.0 days, respectively, versus 1.5 days). Empty defects showed incomplete healing and dedifferentiation/heterotopic differentiation; OATS-filled defects displayed advanced bone healing with remaining cartilage gaps and orthotopic expression of bone and cartilage markers. Minimally-invasive, medial parapatellar surgery of OC defects on the sheep MFC allows rapid and low-trauma recovery and appears well-suited for implant testing. KW - Osteochondral stifle joint defect KW - Sheep animal model KW - Minimally-invasive parapatellar approach PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-520180 SN - 2075-1729 VL - 10 IS - 12 SP - 1 EP - 14 PB - MDPI CY - Basel AN - OPUS4-52018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Schork, B. A1 - Kaffenberger, M. A1 - Oechsner, M. A1 - Kucharzcyk, P. A1 - Hensel, J. A1 - Bernhard, J. A1 - Tchuindjang, D. T1 - The effect of the local and global weld geometry as well as material defects on crack initiation and fatigue strength N2 - The paper provides an application of the IBESS approach to the investigation of the influence of various parameters of the global and local weld geometry as well as material defects on the fatigue strength of weldments. For this purpose, the global weld parameters, such as the weld toe radius, the flank angle, the excess weld metal, local secondary notches (in the present study as a measure of surface imperfections) and inclusions sizes have been determined as statistical distributions for different joint types and geometries and two steels of different strengths. The results are in line with literature data and reveal the potential of the theoretical approach to predict the correct trends. The combination with an advanced weld quality system has been demonstrated to be possible. KW - Weldments KW - Fatigue strength KW - Fracture mechanics KW - Weld geometry KW - Inclusions KW - Multiple crack initiation PY - 2018 U6 - https://doi.org/10.1016/j.engfracmech.2017.07.001 SN - 0013-7944 SN - 1873-7315 VL - 198 SP - 103 EP - 122 PB - Elsevier AN - OPUS4-46858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Schork, B. A1 - Hensel, J. A1 - Kucharczyk, P. A1 - Tchoffo Ngoula, D. A1 - Tchuindjang, D. A1 - Bernhard, J. A1 - Beckmann, C. T1 - Fatigue and fracture of weldments - The IBESS approach for the determination of the fatigue life and strength of weldments by fracture mechanics analysis N2 - The acronym IBESS stands for "Integrale Bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen" which, translated from German, means "integral fracture mechanics determination of the fatigue strength of welds". the method introduced in this study is the outcome of a German Research cluster in which eight partners were involved. A list of them is found at the end this study. The IBESS method is characterized by a number of partially novel aspects and elements of fracture mechanics applied to the evaluation of fatigue stength of welds. The most important ones are: (a) Determination of fatigue crack propagation for mechanically/physically short and long cracks. (b) Determination of an elastic-plastic crack driving force for the treatment of mechanically short cracks. To that purpose an analytical expression for the cyclic J-integral was developed and validated against finite element results. (c) The gradual build-up of the crack closure phenomenon is determined by using cyclic R-curves which describe the crack size dependency of the fatigue crack propagation threshold in the physically short crack growth regime. (d) A physically meaningful initial crack size is defined for total life consideration. It is based on a two-criteria approach. Based on a cyclic R-curve analysis, the crack size at crack arrest is determined as a lower bound. If, however, a pre-existing crack-like defect is larger than this, its dimensions define the initial crack size. (e) Multiple crack propagation at the weld toe is considered. (f) In conjunction with this, the variation of the weld toe geometry is considered in a stochastic model. (g) As a result, both the fatigue limit (defined for 107 loading cycles) and the finite life (high cycle) fatigue S-N curve are obtained statistically. (h) At various analysis steps, parametric equations have been developed which allow for analytical calculations instead of complete stochastic analyses based on finite elements which are unrealistic even at present. (i) The method has been validated with a large number of S-N curves including two materials, three weldment types with two geometries, each referring to differnt manufacturing technologies and the as-welded and stressrelieved state. (j) Althrough not finally solved, an extended discussion is provided on the issue of welding residual stresses including their redistribution under cyclic loading. (k) A number of simplifications is proposed at lower analyses levels which, however, partly lack complete validation by now. KW - Crack initation KW - Short crack KW - Fracture of weldments KW - IBESS PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-468853 UR - https://www.kriso.ee/db/9783030040727.html SN - 978-3-03004-072-7 SP - 1 EP - 189 PB - Springer-Verlag CY - Berlin AN - OPUS4-46885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Schork, B. A1 - Hensel, J. A1 - Kucharczyk, P. A1 - Ngoula, D. A1 - Tchuindjang, D. A1 - Bernhard, J. A1 - Beckmann, C. T1 - The IBESS approach for the determination of the fatigue life and strength of weldments by fracture mechanics analysis N2 - This book provides a comprehensive and thorough guide to those readers who are lost in the often-confusing context of weld fatigue. It presents straightforward information on the fracture mechanics and material background of weld fatigue, starting with fatigue crack initiation and short cracks, before moving on to long cracks, crack closure, crack growth and threshold, residual stress, stress concentration, the stress intensity factor, J-integral, multiple cracks, weld geometries and defects, microstructural parameters including HAZ, and cyclic stress-strain behavior. The book treats all of these essential and mutually interacting parameters using a unique form of analysis. KW - Fatigue crack propagation KW - Cyclic J-integral KW - Cyclic R-curve analysis KW - Fatigue S-N curve KW - HAZ PY - 2019 SN - 978-3-030-04072-7 SN - 978-3-030-04073-4 U6 - https://doi.org/10.1007/978-3-030-04073-4 SP - 1 EP - 130 PB - Springer CY - Cham AN - OPUS4-47576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Braun, Ulrike A1 - Balabanovich, Aliaksandr A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. T1 - Pyrolysis and fire behaviour of epoxy systems containing a novel 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-(DOPO)-based diamino hardener N2 - Highly soluble 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-(DOPO)-based diamino hardener (2), bearing its amino groups directly on the DOPO framework, is investigated with respect to its use as a reactive flame retardant in thermosets. A mechanism for decomposition of the corresponding phosphorus-modified epoxy resin system based on a diglycidylether of bisphenol A DGEBA and 2 (DGEBA/2) is proposed and compared to the systems using DGEBA and 4,4'-diaminodiphenylsulfon (DGEBA/DDS) and to a similar system based on the structurally comparable non-reactive DOPO-based compound (DGEBA/DDS/1). Additive 1 changed the decomposition characteristics of the epoxy resin only slightly and phosphorus was released. Incorporating 2 induces two-step decomposition and most of the phosphorus remains in the residue. Furthermore, the fire behaviour of neat epoxy resin systems and a representative carbon fibre-reinforced composite based on DGEBA, DDS and 2 (DGEBA/DDS/2) were examined and compared to that of the analogous composite systems based on DGEBA/DDS and DGEBA/DDS/1. Based on different flame retardancy mechanisms both the reactive compound 2 and the additive compound 1 improve flammability (increase in LOI >13% and achieving V-1 behaviour) of the epoxy resin and composites. Under forced flaming only the flame inhibition of the additive compound 1 acts sufficiently. Lastly, the superior key mechanical properties of the epoxy resin and composite based on 2 are sketched. KW - Decomposition KW - DOPO KW - Flame retardancy KW - Composites KW - Thermosets PY - 2008 U6 - https://doi.org/10.1016/j.eurpolymj.2008.01.017 SN - 0014-3057 SN - 1873-1945 VL - 44 IS - 3 SP - 704 EP - 715 PB - Elsevier CY - Oxford AN - OPUS4-16708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Schartel, Bernhard A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez-Graterol, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. T1 - Novel Phosphorus-Containing Poly(ether sulfone)s and Their Blends with an Epoxy Resin: Thermal Decomposition and Fire Retardancy N2 - Summary: The decomposition of novel phosphorus-containing poly(oxyphenylene-sulfonyl-phenylene-oxy-diphenyl phenylene phosphine oxide) (PSU_I), 2,5-dihydroxy-1-biphenylene-phosphine oxide based polysulfone (PSU_II), poly(sulfonyl-diphenylphenylene phosphonate) (PSU_P) and bisphenol A-based polysulfone (PSU) is studied. The influence of the chemical structure, charring and phosphorus release is discussed based on the mass loss, kinetics and products. The pyrolysis and fire behaviour of blends with epoxy resin (EP) are studied. For EP-PSU_II, phosphorus initiates water elimination and changes the decomposition pathway of EP. The fire behaviour of EP-PSU shows some improvements, whereas the heat release rate is crucially reduced for EP-PSU_II due to simultaneous char formation and flame inhibition. KW - Epoxy KW - Flame retardance KW - High performance polymers KW - Polysulfones KW - Thermogravimetric analysis (TGA) PY - 2006 U6 - https://doi.org/10.1002/macp.200600182 SN - 1022-1352 SN - 1521-3935 VL - 207 IS - 16 SP - 1501 EP - 1514 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-12650 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Balabanovich, Aliaksandr A1 - Knoll, Uta A1 - Braun, Ulrike A1 - Schartel, Bernhard T1 - Novel Phosphorus-containing Hardeners with Tailored Chemical Structures for Epoxy Resins: Synthesis and Cured Resin Properties N2 - A comparative evaluation of systematically tailored chemical structures of various phosphorus-containing aminic hardeners for epoxy resins was carried out. In particular, the effect of the oxidation state of the phosphorus in the hardener molecule on the curing behavior, the mechanical, thermomechanical, and hot-wet properties of a cured bifunctional bisphenol-A based thermoset is discussed. Particular attention is paid to the comparative pyrolysis of neat cured epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (with a phosphorus content of about 2.6 wt %) and of the fire behavior of their corresponding carbon fiber-reinforced composites. Comparatively faster curing thermosetting system with an enhanced flame retardancy and adequate processing behavior can be formulated by taking advantage of the higher reactivity of the phosphorus-modified hardeners. For example, a combination of the high reactivity and of induced secondary crosslinking reactions leads to a comparatively high Tg when curing the epoxy using a substoichiometric amount of the phosphinate-based hardener. The overall mechanical performance of the materials cured with the phosphorus-containing hardeners is comparable to that of a 4,4-DDS-cured reference system. While the various phosphorus-containing hardeners in general provide the epoxy-based matrix with enhanced flame retardancy properties, it is the flame inhibition in the gas phase especially that determines the improvement in fire retardancy of carbon fiber-reinforced composites. In summary, the present study provides an important contribution towards developing a better understanding of the potential use of such phosphorus-containing compounds to provide the composite matrix with sufficient flame retardancy while simultaneously maintaining its overall mechanical performance on a suitable level. KW - Flame retardance KW - Organo-phosphorus compounds KW - Fracture toughness PY - 2007 SN - 0021-8995 SN - 1097-4628 VL - 105 IS - 5 SP - 2744 EP - 2759 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-15071 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artner, J. A1 - Ciesielski, M. A1 - Ahlmann, M. A1 - Walter, O. A1 - Döring, M. A1 - Perez, R.M. A1 - Altstädt, V. A1 - Sandler, J.K.W. A1 - Schartel, Bernhard T1 - A novel and effective synthetic approach to 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) Derivatives N2 - Starting from trivalent 10-alkoxy-10H-9-oxa-10-phosphaphenanthrenes, a broad range of DOPO derivatives was synthesized via transesterification with aliphatic alcohols and subsequent Michaelis-Arbuzov rearrangement using catalytic amounts of p-toluenesulfonic acid methylester. Due to the considerable differences in the nature of the alcohols employed, several procedures for processing them are presented. KW - DOPO KW - Flame retardant KW - Michaelis-Arbuzov rearrangement KW - Transesterification PY - 2007 U6 - https://doi.org/10.1080/10426500701407417 SN - 1042-6507 SN - 0308-664X VL - 182 IS - 9 SP - 2131 EP - 2148 PB - Taylor & Francis CY - Philadelphia, USA AN - OPUS4-15705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artner, J. A1 - Ciesielski, M. A1 - Walter, O. A1 - Döring, M. A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Schartel, Bernhard T1 - A novel DOPO-based diamine as hardener and flame retardant for epoxy resin systems N2 - 10-Ethyl-9-oxa-10-phosphaphenanthrene-10-oxide (1) can be nitrated using acetic anhydride and fuming nitric acid. The nitro group is reduced using palladium on charcoal and hydrogen. These reaction conditions are used for the synthesis of an analogous DOPO-based diaminic hardener (7). An evaluation of the curing behavior, mechanical properties and flammability of a neat resin made of DGEBA and 7 (DGEBA + 7) and of a carbon fiber-reinforced resin made of DGEBA, 4,4-diaminodiphenylsulfon (DDS) and 7 (DGEBA + DDS + 7) shows the potential of this hardener to lead to flame-retardant systems while keeping relevant properties on a high level; especially when compared to a similar system (DGEBA + DDS + 1). KW - Composites KW - Epoxy resins KW - Synthesis KW - Flame retardancy KW - Mechanical properties PY - 2008 U6 - https://doi.org/10.1002/mame.200700287 SN - 1438-7492 SN - 1439-2054 VL - 293 IS - 6 SP - 503 EP - 514 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-17624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Schartel, Bernhard ED - Schartel, Bernhard T1 - Flame retardant epoxy resin system for liquid composite moulding applications KW - Epoxy resin KW - Fire retardancy PY - 2007 SN - 978-3-8334-8873-3 SP - 69 EP - 84 PB - Books on Demand GmbH CY - Norderstedt AN - OPUS4-17627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard T1 - Effective halogen-free flame retardancy for a monocomponent polyfunctional epoxy using an oligomeric organophosphorus compound N2 - Oligomeric organo-phosphorus flame retardants are proposed for a monocomponent polyfunctional epoxy resin system (RTM6) without significantly deteriorating the overall performance of the resulting material. KW - DOPO KW - Epoxy resin KW - Fire retardancy KW - LOI PY - 2006 U6 - https://doi.org/10.1007/s10853-006-1079-3 SN - 0022-2461 SN - 1573-4803 VL - 41 IS - 24 SP - 8347 EP - 8351 PB - Springer Science + Business Media B.V. CY - New York, USA AN - OPUS4-14112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard A1 - Knoll, Uta A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. T1 - Influence of the oxidation state of phosphorus on the decomposition and fire behaviour of flame-retarded epoxy resin composites N2 - A systematic and comparative evaluation of the pyrolysis of halogen-free flame-retarded epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (phosphorus contents around 2.6 wt.%) and the fire behaviour of their carbon fibre composites is presented. Decomposition pathways are proposed based on the thermal analysis (TG), TG coupled with evolved gas analysis (TG-FTIR), kinetics and analysis of the residue with FTIR and XPS. All organophosphorus-modified hardeners containing phenoxy groups lead to a reduced decomposition temperature and mass loss step for the main decomposition of the cured epoxy resin. With increasing oxidation state of the phosphorus the thermally stable residue increases, whereas the release of phosphorus-containing volatiles decreases. The flammability of the composites was investigated with LOI and UL 94 and the fire behaviour for forced-flaming conditions with cone calorimeter tests performed using different irradiations. The flame retardancy mechanisms are discussed. With increasing oxidation state of the phosphorus additional charring is observed, whereas the flame inhibition, which plays the more important role for the performance of the composites, decreases. The processing and the mechanical performance (delamination resistance, flexural properties and interlaminar bonding strength) of the fibre-reinforced composites containing phosphorus were maintained at a high level and, in some cases, even improved. The potential for optimising flame retardancy while maintaining mechanical properties is highlighted in this study. KW - Fire retardant KW - Composites KW - Organophosphorus-containing epoxy resin PY - 2006 U6 - https://doi.org/10.1016/j.polymer.2006.10.022 SN - 0032-3861 SN - 1873-2291 VL - 47 IS - 26 SP - 8495 EP - 8508 PB - Springer CY - Berlin AN - OPUS4-14054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Balabanovich, Aliaksandr A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Artner, J. A1 - Ciesielski, M. A1 - Döring, M. A1 - Perez, R. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. T1 - Pyrolysis of Epoxy Resins and Fire Behavior of Epoxy Resin Composites Flame-Retarded with 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide Additives N2 - The pyrolysis of an epoxy resin and the fire behavior of corresponding carbon fiber-reinforced composites, both flame-retarded with either 10-ethyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide or 1,3,5-tris[2-(9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide-10-)ethyl]1, 3,5-triazine-2,4,6(1H,3H,5H)-trione, are investigated. The different fire retardancy mechanisms are discussed, and their influence on the fire properties assessed, in particular for flammability (limiting oxygen index, UL 94) and developing fires (cone calorimeter with different external heat fluxes of 35, 50, and 70 kW m-2). Adding the flame retardants containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide affects the fire behavior by both condensed phase and gas phase mechanisms. Interactions between the additives and the epoxy resin result in a change in the decomposition pathways and an increased char formation. The release of phosphorous products results in significant flame inhibition. The fire properties achieved are thus interesting with respect to industrial exploration. KW - Flame retardance KW - Thermosets KW - Composites KW - Thermogravimetric analysis (TGA) KW - Pyrolysis KW - High performance polymers KW - Epoxy resin PY - 2007 SN - 0021-8995 SN - 1097-4628 VL - 104 IS - 4 SP - 2260 EP - 2269 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-14573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bienge, J.-E. A1 - Illerhaus, Bernhard A1 - Epperlein, J. ED - Szallies, agrathaer GmbH, Isabell T1 - Blick in den Boden N2 - Computertomographische Untersuchungen in einer Studie zum vergleichenden Wurzelwachstum von Raps unter verschiedenen Bedingungen der Bodenbearbeitung. T2 - 20 Jahre Praxisversuch Lietzen Ackerbau und Forschung auf dem Weg in die Zukunft Feldtag in der Komturei Lietzen CY - Komturei Lietzen, Germany DA - 19.5.2016 KW - Computer Tomographie PY - 2016 SP - 28 EP - 29 AN - OPUS4-38144 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Kunze, Ralf A1 - Hennecke, Manfred A1 - Kettner, A. A1 - Wendorff, J. H. T1 - On the thermal behaviour and thermo-oxidative stability of liquid crystalline triphenylene compounds N2 - Columnar discotic materials are considered for applications in the area of photoconductivity and light-emitting diodes. A major requirement is their stability at elevated temperatures and in the presence of oxygen. The thermal and thermo-oxidative behaviour of discotic triphenylene derivatives was investigated by us using various methods, in particular by chemiluminescence (CL), UV-vis absorption spectroscopy and in situ thermogravimetry-mass spectroscopy (TG-MS). Various degradation processes are described for increasing temperature, and their influences on functional properties are discussed. KW - Liquid crystal KW - Oxidation KW - Thermogravimetry PY - 1999 U6 - https://doi.org/10.1002/(SICI)1099-0712(199903/04)9:2<55::AID-AMO366>3.3.CO;2-R SN - 1057-9257 SN - 1099-0712 VL - 9 IS - 2 SP - 55 EP - 64 PB - Wiley CY - Chichester AN - OPUS4-732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Wendorff, J. H. T1 - Molecular composites for molecular reinforcement: A promising concept between success and failure N2 - The basic principles of molecular reinforcement and especially the specific approaches to obtain homogeneous composites with molecularly dispersed rigid rods are focused on and discussed. Brief overviews and successful examples of the available data covering the main characteristics are summarized. KW - Verbundwerkstoffe KW - Molecular Reinforcement KW - Homogene Mischbarkeit PY - 1999 SN - 0032-3888 SN - 1548-2634 VL - 39 IS - 1 SP - 128 EP - 151 PB - Wiley CY - Hoboken, NY AN - OPUS4-731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen A1 - Bamberg, J. A1 - Heutling, F. T1 - 3D Refraction Computed Tomography Applied to Metal Matrix Composites N2 - For the first time Metal Matrix Composites (MMC) have been investigated by 3D Computed Tomography combined with enhanced interface contrast due to X-ray refraction. X-ray refraction is a relatively new approach for the characterization of advanced materials. The related techniques of Refraction Topography and Refraction Computed Tomography have been developed and applied at our laboratory during the last decade to meet the actual demand for improved nondestructive characterization of high performance composites, ceramics and other low density materials and components. X-ray refraction occurs, when X-rays crosses interfaces of spherical or cylindrical shape (e.g. pores or fibres) in the same way as visible light is refracted by lenses. These X-ray optical effects can be observed at small scattering angles of few minutes of arc as the refractive index n of X-rays is nearly unity (n = 1 – 10-6). Due to the short X-ray wavelength of about 0.1 nm the technique determines the amount of inner surfaces and interfaces of nanometer dimensions. The technique is expected to solve many problems in understanding the meaning of micro and sub micro structures in materials science. With the results of the CT investigation, some questions could be clarified for a better understanding of fatigue failure mechanisms under cyclic loading conditions. The specimens for the test programme have been provided by MTU Aero Engines. They consist of a titanium matrix (Ti6242) reinforced by SiC fibres (SCS6). The investigations have been performed at the materials research station of BAM (BAMline) at the Synchrotron Facility BESSY in Berlin, Germany. T2 - 35th International SAMPE technical conference CY - Dayton, OH, USA DA - 2003-09-28 KW - Non-Destructive Inspection (NDI) KW - Characterization KW - Titanium Metal Matrix Composites (Ti-MMC) KW - Ti6242 KW - SCS6 PY - 2003 SN - 0-938994-95-6 PB - SAMPE CY - Covina, Calif. AN - OPUS4-2780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen A1 - Bamberg, J. A1 - Heutling, F. T1 - Micro Crack Characterization of Metal Matrix Composites by 3D-Refraction-Computed-Tomography T2 - 16th World Conference on Nondestructive Testing CY - Montreal, Canada DA - 2004-08-30 KW - NDE KW - X-ray refraction KW - Composites KW - MMC PY - 2004 SP - 9 pages PB - International Committee for Non-Destructive Testing CY - Montreal AN - OPUS4-5486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Bernhard A1 - Gollmer, W. A1 - Odelga, J. T1 - Zur zerstörungsfreien Prüfung beheizbarer Beläge mit Infrarotverfahren PY - 1974 SN - 0340-384X VL - 25 IS - 9 SP - 364 EP - 367 PB - Straßenbau, Chemie u. Technik Verl. CY - Heidelberg AN - OPUS4-7978 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen A1 - Bamberg, J. A1 - Heutling, F. T1 - X-Ray Refraction Topography and Computed Tomography for NDE of Lightweight Materials T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Synchrotron Refraction CT KW - MMC KW - Bragg-Magnification PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 9(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, J. A1 - Kiechle, H. A1 - Ewert, Uwe A1 - Rädel, Christoph A1 - Redmer, Bernhard T1 - Mobile Computer Tomography for In-Service Inspection in Nuclear Power Plants T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Röntgen KW - Digitale Detektoren KW - Tomographie KW - TomoCAR KW - Schweißnähte KW - Analyse KW - Bewertung PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 6(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-14376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen A1 - Bamberg, J. A1 - Heutling, F. T1 - Refraction computed tomography - Application to metal matrix composites N2 - Erstmals wurden MMCs mit Hilfe der Interface-Kontrast verstärkenden Röntgen-Refraktions-Technik in Kombination mit der 3D-CT-Technik untersucht. Die Methode der Röntgen-Refraktions-Topography sowie der Röntgen-Refraktions-Tomography wurden in den letzten Jahren speziell für die zerstörungsfreie Charakterisierung von Leichtbau-Hochleistungs-Werkstoffen wie Verbund-Werkstoffen und Keramiken entwickelt. Die Technik basiert auf der Refraktion von Röntgenlicht an Grenzflächen zwischen Bereichen unterschiedlicher Elektronendichte wie z.B. Faser- und Matrix-Werkstoff. Auf Grund der kurzen Röntgen-Wellenlänge hat der Brechungsindex einen Wert dicht bei eins, sodass der Streuwinkel nur wenige Bogenminuten beträgt. Der Vorteil der kurzen Wellenlänge besteht jedoch darin, dass Poren und Risse detektiert werden können, deren Größe im Nanometerbereich liegen. Damit kann die Refraktions-Technik zum besseren Verständnis von Mikro- und Submikro-Strukturen in der Materialwissenschaft eingesetzt werden. Mit der hier vorgestellten Refraktions-CT wurden Ermüdungsmechanismen an MMCs, bestehend aus SiC-Faser verstärktem Titan (Ti6242) untersucht. Die Messungen wurden am Röntgen-Messplatz der BAM (BAMline) am Synchrotron-Speicherring-BESSY in Berlin Adlershof durchgeführt. KW - X-ray refraction KW - Computed tomography PY - 2004 U6 - https://doi.org/10.3139/120.100592 SN - 0025-5300 VL - 46 IS - 6 SP - 314 EP - 319 PB - Carl Hanser Verlag CY - München AN - OPUS4-5870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz-Forberg, Bernd A1 - Zeisler, Peter A1 - Droste, Bernhard A1 - Kondratiev, A. A1 - Kozlov, J. A1 - Tichinov, N. T1 - Soviet-German cooperation in safety improvements of spent fuel transport casks N2 - The paper gives a survey of the Soviet (Russian) -German activities which started in 1988 with the objective of creating a long-term scientific-technical cooperation in the field of transport and storage casks for spent nuclear fuel. The first step, i.e., the step of informing each other about the state of development is done. The more complicated second phase with concerted common activities of both the Russian and German competent authorities and industrial enterprises is intended to start in the near future. T2 - PATRAM ´92 - 10th International symposium on the packaging and transportation of radioactive materials CY - Yokohama, Japan DA - 1992-09-13 PY - 1992 VL - 1 SP - 343 EP - 350 AN - OPUS4-21824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kumano, Y. A1 - Droste, Bernhard A1 - Hirose, M. A1 - Harvey, J. A1 - Reiche, I.. A1 - Wolff, Dietmar A1 - McConnell, P. A1 - Varley, K. T1 - Overview of the IAEA's joint working group on integrated safety case for dual purpose casks T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 2013-08-18 PY - 2013 SP - 1 EP - 9(?) PB - Omnipress AN - OPUS4-30140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, C. A1 - Battig, Alexander A1 - Schartel, Bernhard A1 - Siegel, R. A1 - Senker, J. A1 - von der Forst, I. A1 - Unverzagt, C. A1 - Agarwal, S. A1 - Möglich, A. A1 - Greiner, A. T1 - Investigation of the Thermal Stability of Proteinase K for the Melt Processing of Poly(L‑lactide) N2 - The enzymatic degradation of aliphatic polyesters offers unique opportunities for various use cases in materials science. Although evidently desirable, the implementation of enzymes in technical applications of polyesters is generally challenging due to the thermal lability of enzymes. To prospectively overcome this intrinsic limitation, we here explored the thermal stability of proteinase K at conditions applicable for polymer melt processing, given that this hydrolytic enzyme is well established for its ability to degrade poly(L-lactide) (PLLA). Using assorted spectroscopic methods and enzymatic assays, we investigated the effects of high temperatures on the structure and specific activity of proteinase K. Whereas in solution, irreversible unfolding occurred at temperatures above 75−80 °C, in the dry, bulk state, proteinase K withstood prolonged incubation at elevated temperatures. Unexpectedly little activity loss occurred during incubation at up to 130 °C, and intermediate levels of catalytic activity were preserved at up to 150 °C. The resistance of bulk proteinase K to thermal treatment was slightly enhanced by absorption into polyacrylamide (PAM) particles. Under these conditions, after 5 min at a temperature of 200 °C, which is required for the melt processing of PLLA, proteinase K was not completely denatured but retained around 2% enzymatic activity. Our findings reveal that the thermal processing of proteinase K in the dry state is principally feasible, but equally, they also identify needs and prospects for improvement. The experimental pipeline we establish for proteinase K analysis stands to benefit efforts directed to this end. More broadly, our work sheds light on enzymatically degradable polymers and the thermal processing of enzymes, which are of increasing economical and societal relevance. KW - Enzymatic degradation KW - Poly(L‑lactide) KW - Polyesters KW - biodegradation PY - 2022 U6 - https://doi.org/10.1021/acs.biomac.2c01008 SN - 1525-7797 SN - 1526-4602 VL - 23 IS - 11 SP - 4841 EP - 4850 PB - ACS Publications AN - OPUS4-56292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marti, J. A1 - Schartel, Bernhard A1 - Oñate, E. T1 - Simulation of the burning and dripping cables in fire using the particle finite element method N2 - The behavior of the cable jacket in fire characterized by the tendency to melt and drip constitutes a major source of fire hazard. The reason is that the melted material may convey the flame from one point to another, expanding fire and contributing to the fire load. In this article, the capability of a new computational strategy based on the particle finite element method for simulating a bench-scale cables burning test is analyzed. The use bench-scale test has been previously used to simulate the full-scale test described in EN 50399. As the air effect is neglected, a simple combustion model is included. The samples selected are two cables consisting of a copper core and differently flame retarded thermoplastic polyurethane sheets. The key modeling parameters were determined from different literature sources as well as experimentally. During the experiment, the specimen was burned under the test set-up condition recording the process and measuring the temperature evolution by means of three thermocouples. Next, the test was reproduced numerically and compared with a real fire test. The numerical results show that the particle finite element method can accurately predict the evolution of the temperature and the melting of the jacket. KW - Dripping behavior KW - Particle finite element method KW - Cables in fire KW - Fire behavior KW - Fire simulation KW - Cable bundle PY - 2022 U6 - https://doi.org/10.1177/07349041211039752 SN - 0734-9041 VL - 40 IS - 1 SP - 3 EP - 25 PB - Sage AN - OPUS4-54185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Färber, C. A1 - Titschack, J. A1 - Schönberg, Chr. H. L. A1 - Ehrig, Karsten A1 - Boos, K. A1 - Illerhaus, Bernhard A1 - Asgaard, U. A1 - Bromley, R. G. A1 - Freiwald, A. A1 - Wisshak, M. ED - Bahn, M. ED - Fennel, K. ED - Kesselmeier, J. ED - Naqvi, S. W. A. T1 - Long-term macrobioerosion in the Mediterranean Sea assessed by micro-computed tomography N2 - Biological erosion is a key process for the recycling of carbonate and the formation of calcareous sediments in the oceans. Experimental studies showed that bioerosion is subject to distinct temporal variability, but previous long-term studies were restricted to tropical waters. Here, we present results from a 14-year bioerosion experiment that was carried out along the rocky limestone coast of the island of Rhodes, Greece, in the Eastern Mediterranean Sea, in order to monitor the pace at which bioerosion affects carbonate substrate and the sequence of colonisation by bioeroding organisms. Internal macrobioerosion was visualised and quantified by micro-computed tomography and computer-algorithm-based segmentation procedures. Analysis of internal macrobioerosion traces revealed a dominance of bioeroding sponges producing eight types of characteristic Entobia cavity networks, which were matched to five different clionaid sponges by spicule identification in extracted tissue. The morphology of the entobians strongly varied depending on the species of the producing sponge, its ontogenetic stage, available space, and competition by other bioeroders. An early community developed during the first 5 years of exposure with initially very low macrobioerosion rates and was followed by an intermediate stage when sponges formed large and more diverse entobians and bioerosion rates in-creased. After 14 years, 30 % of the block volumes were occupied by boring sponges, yielding maximum bioerosion rates of 900 g m. KW - Bioerosion KW - Computed tomography KW - Carbonate substrate PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-372709 UR - http://www.biogeosciences.net/13/3461/2016/bg-13-3461-2016.pdf VL - 13 IS - 11 SP - 3461 EP - 3474 PB - Copernicus Publications CY - Göttingen AN - OPUS4-37270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Marco A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen A1 - Bamberg, J. A1 - Heutling, F. ED - Danny Van Hemelrijck, ED - Igor Solodov, ED - Anastasopoulos, Athanasios ED - Gerhard Busse, T1 - Synchrotron-Refraction-Computed-Tomography for NDT and characterisation of lightweight composite materials T2 - 4th International Conference of Emerging Technologies in Non-Destructive Testing (ETNDT 4) CY - Stuttgart, Germany DA - 2007-04-02 KW - Refraction KW - Computed Tomography KW - NDE KW - Ti-MMC PY - 2008 SN - 978-0-415-46476-5 SP - 217 EP - 221 PB - Taylor & Francis CY - London, UK AN - OPUS4-18680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Matthies, Klaus A1 - Erhard, Anton A1 - Ernst, h. A1 - Hübschen, G. A1 - Just, Tilman A1 - Völz, Uwe A1 - Wessels, J. A1 - Boehm, Rainer A1 - Gebhardt, W. A1 - Mrasek, Heinz A1 - Neumann, Eberhard A1 - Redmer, Bernhard A1 - Schmitz, V. A1 - Thomas, Hans-Martin A1 - Walte, F. T1 - Ultraschallprüfung von austenitischen Werkstoffen PY - 2009 SN - 978-3-87155-988-4 IS - 1. Aufl. SP - 1 EP - 464 PB - DVS-Verl. CY - Berlin AN - OPUS4-19897 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hörold, Andreas A1 - Schartel, Bernhard A1 - Trappe, Volker A1 - Korzen, Manfred A1 - Bünker, J. T1 - Fire stability of glass-fibre sandwich panels: The influence of core materials and flame retardants N2 - Fire resistance has become a key property for structural lightweight sandwich components in aviation, shipping, railway vehicles, and construction. The development of future composite materials and components demands adequate test procedures for simultaneous application of compression and fully developed fire. Therefore an intermediate-scale approach (specimen size = 500 mm x 500 mm) is applied with compressive loads (up to 1 MN) and direct application of a burner to one side of the specimens, as established in aviation for severe burn-through tests. The influence of different core structures (polyvinylchloride foam, polyisocyanorate foam reinforced by stitched glass bridges, and balsa wood) was investigated for glass-fibre-reinforced sandwich specimens with and without flame retardants applied on the fabrics, in the matrix, and on surface for each specimen at the same time. Times to failure were increased up to a factor of 4. The intumescent coating prolongs the time to failure significantly. What is more, using the intrinsic potential of the front skin together with the core to protect a load bearing back skin in sandwich panels, the design of the core – here using the wood core – is the most promising approach. KW - Fire resistance KW - Fire stability KW - Glass-fibre-reinforced plastics KW - Composite KW - Core materials PY - 2017 U6 - https://doi.org/10.1016/j.compstruct.2016.11.027 SN - 0263-8223 SN - 1879-1085 VL - 160 SP - 1310 EP - 1318 PB - Elsevier AN - OPUS4-38622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illerhaus, Bernhard A1 - Maenz, S. A1 - Bischoff, S. A1 - Bungartz, M. A1 - Bossert, J. A1 - Kunisch, E. A1 - Kinne, R. ED - Maenz, S. T1 - Micro computer tomography (μCT) set-up for long-term serial measurements, image evaluation, and subsequent compressive strength tests on frozen sheep vertebrae for osteoporosis research N2 - Injection of poly(methyl methacrylate) cements, one standard Treatment for osteoporotic vertebral body fractures, may lead to critical loads and subsequent fractures in adjacent vertebral bodies. Biodegradable calcium phosphate cements (CPC) with bioinductive growth factors may be an alternative, since they have a Young’s modulus comparable to that of cancellous bone. Non-destructive tests with μCT and quantitative Image evaluation are used to assess new bone growth and material resorption following intravertebral injection of CPC. Immediate deep-freezing of excised bone prevents shrinkage or tissue disintegration and the samples have to be kept frozen for all following steps, including transport, μCT measurements, and subsequent biomechanical tests. Here we will report on a set-up to preserve the frozen state of the material and allow stable long-term serial μCT measurements. In addition, the image processing technique for the evaluation of bone growth and selected results on subsequently carried out compressive strength tests will be presented. T2 - WCNDT2016 CY - München, Germany DA - 13.6.2016 KW - Computed tomography KW - Osteoporosis KW - CT PY - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-366410 UR - https://www.ndt.net/?id=19382 VL - BB 158 SP - 1 EP - 7 PB - DGZfP CY - Berlin AN - OPUS4-36641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Madia, Mauro A1 - Schork, B. A1 - Bernhard, J. A1 - Kaffenberger, M. T1 - Multiple crack initiation and propagation in weldments under fatigue loading N2 - The work aims at addressing the modelling and implementation of criteria for multiple crack propagation, including interaction and coalescence, for a more reliable fracture mechanics-based prediction of stress-life curves for weldments. A large experimental work is presented in which micro-cracks have been made visible by heat-tinting at successive stages of fatigue life of the welded specimens. Here the correlation between the number of initiation sites and the applied stress level has been also investigated. The criteria have been implemented in in-house software, which allows multiple fatigue crack propagation, and validated against selected experimental tests. The results have shown that the modelling of multiple crack propagation and interaction is crucial for the prediction of the fatigue strength of weldments, both in finite and infinite life regime. T2 - FDMD 2017 CY - Lecco, Italy DA - 19.09.2017 KW - Weldments KW - Fatigue strength KW - Multiple crack propagation PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-438593 SN - 2452-3216 VL - 7 SP - 423 EP - 430 PB - Elsevier B.V. AN - OPUS4-43859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, J. C. A1 - Battig, Alexander A1 - Urbaniak, T. A1 - Haag, K. A1 - Koschek, K. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials N2 - Recycling of crosslinked fiber-reinforced polymers is difficult. Moreover, as they are often based on flammable resins, additional additives are needed. So-called “vitrimers” open the possibility of Recycling and reprocessing and repairing with dynamically crosslinked chemistries. To date, vitrimer-based composites still need flame retardant additives, such as organophosphates. An additive-free vitrimer composite has not been reported. Herein, we synthesized an intrinsic flame-retardant vitrimer, relying on vinylogous polyurethanes containing covalently installed phosphonates as flame-retardant units and prepared glassfiber-reinforced composites. We studied recycling and flame retardant properties and compared the data to phosphorus-free vitrimers and conventional epoxy resins (with and without additive flame retardant). Our phosphonate-based vitrimer proved in first tests, a flame retardant effect comparable to commercial flame retardant resins. The bending strength and bending modulus for the phosphorus-vitrimer glass fiber composites were comparable to glass fiber composites with permanently cross-linked epoxies. In summary, we were able to prove that the covalent installation of phosphonates into vitrimers allows the preparation of recyclable and intrinsic flame retardant composites that do not need flame retardant additives. We believe this concept can be expanded to other polymer networks and additives to generate recyclable and sustainable high-performance materials. KW - Vitrimer KW - Flame retardant KW - Recyclable KW - Organophosphonate KW - Polyurethane PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-510889 VL - 11 IS - 30 SP - 4933 EP - 4941 AN - OPUS4-51088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Perret, Birgit A1 - Dittrich, Bettina A1 - Ciesielski, M. A1 - Krämer, J. A1 - Müller, P. A1 - Altstädt, V. A1 - Zang, L. A1 - Döring, M. T1 - Flame retardancy of polymers: the role of specific reactions in the condensed phase N2 - Condensed-phase mechanisms play a major role in fire-retardant polymers. Generations of development have followed the concept of charring to improve fire properties. Whereas the principal reactions are believed to be known, the specific description for multicomponent systems is lacking, as is the picture across different systems. A two-step approach is proposed in general, and also presented in greater detail. The second step covers the specific reactions controlling charring, whereas the actual reactants are provided in the preceding step. This model consistently incorporates the variety of structure–property relationships reported. A comprehensive case study is presented on seven phosphorus flame retardants in two epoxy resins to breathe life into the two-step approach. KW - Charring KW - Epoxy KW - Flame retardancy KW - Pyrolysis KW - Thermogravimetric analysis (TGA) PY - 2016 U6 - https://doi.org/10.1002/mame.201500250 SN - 1438-7492 SN - 1439-2054 VL - 301 IS - 1 SP - 9 EP - 35 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-35273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Hyperbranched phosphorus flame retardants: multifunctional additives for epoxy resins N2 - We successfully synthesized multifunctional P-based hyperbranched polymeric flame retardants (hb-FRs) with varying oxygen-to-nitrogen (O : N) content and characterized them via 1H and 31P NMR and GPC. Their miscibility in epoxy resins (EP) and impact on glass-transition temperatures (Tg) were determined via differential scanning calorimetry (DSC). Using thermogravimetric and evolved gas Analysis (TGA, TG-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC-MS), hot stage FTIR, flammability tests UL-94 and LOI, fire testing via cone calorimetry, residue analysis via scanning electron microscopy (SEM) and elemental analysis, detailed decomposition mechanisms and modes of action are proposed. hb-polymeric FRs have improved miscibility and thermal stability, leading to high FR performance even at low loadings. Polymeric, complex FRs increase flame retardancy, mitigate negative effects of low molecular weight variants, and can compete with commercial aromatic FRs. The results illustrate the role played by the chemical structure in flame retardancy and highlight the potential of hb-FRs as multifunctional additives. KW - Flame retardant KW - Hyperbranched PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-486589 SN - 1759-9962 SN - 1759-9954 VL - 10 IS - 31 SP - 4346 EP - 4358 PB - RSC AN - OPUS4-48658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lenz, J. A1 - Pospiech, D. A1 - Paven, M. A1 - Albach, R. W. A1 - Günther, Martin A1 - Schartel, Bernhard A1 - Voit, B. T1 - Improving the Flame Retardance of Polyisocyanurate Foams by Dibenzo[d,f][1,3,2]dioxaphosphepine 6-Oxide-Containing Additives N2 - A series of new flame retardants (FR) based on dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were developed previously. In this study, we examine the fire behavior of the new flame retardants in polyisocyanurate (PIR) foams. The foam characteristics, thermal decomposition, and fire behavior are investigated. The fire properties of the foams containing BPPO-based derivatives were found to depend on the chemical structure of the substituents. We also compare our results to state-of-the-art non-halogenated FR such as triphenylphosphate and chemically similar phosphinate, i.e. 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO), based derivatives to discuss the role of the phosphorus oxidation state. KW - Polyisocyanurate KW - Dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide KW - Phospha-Michael addition KW - Flame retardant KW - Foams PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-485590 SN - 2073-4360 VL - 11 IS - 8 SP - Article 1242 PB - MDPI AN - OPUS4-48559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, J. C. A1 - Battig, Alexander A1 - Velencoso, M. M. A1 - Pollok, D. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins N2 - The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin Metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs. KW - Phosphorus KW - Metathesis KW - Dendritic KW - Cone calorimeter KW - Fire test PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-494535 SN - 1420-3049 VL - 24 IS - 21 SP - 3901 PB - MDPI AN - OPUS4-49453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Matrix matters: Hyperbranched flame retardants in aliphatic and aromatic epoxy resins N2 - We synthesized a library of phosphorus-based flame retardants (phosphates and phosphoramides of low and high molar mass) and investigated their behavior in two epoxy resins (one aliphatic and one aromatic). The pyrolytic and burning behavior of the two resins (via TGA, TG-FTIR, Hot stage FTIR, Py-GC/MS, PCFC, DSC, LOI, UL-94, Cone calorimeter) are analyzed and compared to the results of flame retardant (FR)-containing composites. A decomposition pathway incorporating the identified modes of action and known chemical mechanisms is proposed. The overlap of decomposition temperature (Tdec) ranges of matrix and FR determines the efficacy of the system. Low molar mass FRs strongly impact material properties like Tg but are very reactive, and high molar mass variants are more thermally stable. Varying PeO and PeN content of the FR affects decomposition, but the chemical structure of the matrix also guides FR behavior. Thus, phosphates afford lower fire load and heat release in aliphatic epoxy resins, and phosphoramides can act as additives in an aromatic matrix or a reactive FRs in aliphatic ones. The chemical structure and the structure-property relationship of both FR and matrix are central to FR performance and must be viewed not as two separate but as one codependent system. KW - Flame retardant KW - Phosphate KW - Phosphoramide KW - Epoxy resin KW - Hyperbranched polymer PY - 2019 U6 - https://doi.org/10.1016/j.polymdegradstab.2019.108986 SN - 0141-3910 VL - 170 SP - 108986 PB - Elsevier Ltd. AN - OPUS4-49456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, J. C. A1 - Battig, Alexander A1 - Kuckhoff, T. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - First phosphorus AB2 monomer for flame-retardant hyperbranched polyphosphoesters: AB2vs. A2 + B3 N2 - Branched polymers are an important class of polymers with a high number of terminal groups, lower viscosity compared to their linear analogs and higher miscibility, which makes them especially interesting for flame retardant applications, where the flame retardants (FR) are blended with another polymer matrix. Hyperbranched polyphosphoesters (hbPPEs) are gaining more and more interest in the field of flame retardancy, as low molar mass FRs often have the disadvantage of blooming out or leaching, which is not desired in consumer products. Here, we present the first phosphorus-based AB2 monomer for the synthesis of hbPPEs and assess its flame-retardant performance in an epoxy resin compared to a hbPPE synthesized by an A2 + B3 approach. The hbPPE synthesized from an AB2 monomer exhibited a slightly higher performance compared to a similar hbPPE, which was prepared by A2 + B3 polyaddition, probably due to its higher phosphorus content. KW - Polyphosphoester KW - Hyperbranched KW - Flame retardant KW - Synthesis PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-497570 SN - 1759-9962 VL - 10 IS - 43 SP - 5920 EP - 5930 PB - RSC AN - OPUS4-49757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tan, Yi A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Kukofka, Tobias A1 - Ruder, J. A1 - Schartel, Bernhard T1 - Durability of the flame retardance of ethylene-vinyl acetate copolymer cables: Comparing different flame retardants exposed to different weathering conditions N2 - Scientific publications addressing the durability of the flame retardance of cables during their long-term application are rare and our understanding lacks. Three commercial flame retardants, aluminum hydroxide, aluminum diethyl phosphinate (AlPi-Et), and intumescent flame retardant based on ammonium polyphosphate, applied in ethylene-vinyl acetate copolymer (EVA) model cables, are investigated. Different artificial aging scenarios were applied: accelerated weathering (UV-irradiation/temperature/rain phases), humidity exposure (elevated temperature/humidity), and salt spray exposure. The deterioration of cables’ surface and flame retardancy were monitored through imaging, color measurements, attenuated total reflectance Fourier transform infrared spectroscopy, and cone calorimeter investigations. Significant degradation of the materials’ surface occurred. The flame retardant EVA cables are most sensitive to humidity exposure; the cable with AlPi-Et is the most sensitive to the artificial aging scenarios. Nevertheless, substantial flame retardance persisted after being subjected for 2000 h, which indicates that the equivalent influence of natural exposure is limited for several years, but less so for long-term use. KW - Durability KW - Flame retardant KW - Cable KW - Weathering KW - Cone calorimeter PY - 2020 U6 - https://doi.org/10.1002/APP.47548 SN - 0021-8995 VL - 137 IS - 1 SP - 47548 PB - Wiley AN - OPUS4-50237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Sulfur's role in the flame retardancy of thio-ether–linked hyperbranched polyphosphoesters in epoxy resins N2 - Hyperbranched polyphosphoesters are promising multifunctional flame retardants for epoxy resins. These polymers were prepared via thiol-ene polyaddition reactions. While key chemical transformations and modes of actions were elucidated, the role of sulfur in the chemical composition remains an open question. In this study, the FR-performance of a series of phosphorus-based flame retardant additives with and without sulfur (thioethers or sulfones) in their structure are compared. The successful synthesis of thio-ether or sulfone-containing variants is described and verified by 1H and 31P NMR, also FTIR and MALDI-TOF. A decomposition process is proposed from pyrolytic evolved gas analysis (TG-FTIR, Py-GC/MS), and flame retardancy effect on epoxy resins is investigated under pyrolytic conditions and via fire testing in the cone calorimeter. The presence of sulfur increased thermal stability of the flame retardants and introduced added condensed phase action. Likely, Sulfur radical generation plays a key role in the flame-retardant mode of action, and sulfones released incombustible SO2. The results highlight the multifunctionality of the hyperbranched polymer, which displays better fire performance than its low molar mass thio-ether analogue due to the presence of vinyl groups and higher stability than its monomer due to the presence of thio-ether groups. KW - Phosphoester KW - Hyperbranched KW - Sulfur KW - Thio-ether KW - Flame retardant KW - Epoxy resin PY - 2020 U6 - https://doi.org/10.1016/j.eurpolymj.2019.109390 SN - 0014-3057 VL - 122 SP - 109390 PB - Elsevier Ltd. AN - OPUS4-50238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tan, Yi A1 - Wachtendorf, Volker A1 - Kukofka, Tobias A1 - Klack, Patrick A1 - Ruder, J. A1 - Lin, Xuebao A1 - Schartel, Bernhard T1 - Degradation of flame retardance: A comparison of ethylene‐vinyl acetate and low‐density polyethylene cables with two different metal hydroxides N2 - The durability of flame retardancy is a challenge for cables over long lifetimes. The degradation of flame retardance is investigated in two kinds of exposures, artificial weathering and humidity. In this basic study, typical mineral flame retardants in two polymers frequently used in cable jackets are investigated to get the fundamental picture. Aluminum hydroxide (ATH) and magnesium hydroxide (MDH) are compared in ethylene‐vinyl acetate (EVA), and further in EVA and linear low‐density polyethylene (LLDPE) cables containing the same ATH. The changes in chemical structure at the surface are studied through attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), the formation of cracks, and changes in color are investigated. The cone calorimeter and a bench scale fire testing cable module are utilized to evaluate the fire behavior of the cables. Although the flame retardancy deteriorated slightly, it survived harsh exposure conditions for 2000 h. Compared to EVA/MDH and LLDPE/ATH, the fire behavior of EVA/ATH is the least sensitive. Taken together, all of the results converge to estimate that there will be no problem with flame retardancy performance, for materials subjected to natural exposure for several years; the durability of fire retardancy is questionable for longer periods, and thus requires further investigation. KW - Durability KW - Flame retardant KW - Aluminum hydroxide (ATH) KW - Magnesium hydroxide KW - Ethylene-vinyl acetate KW - Cables KW - Weathering PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-519573 VL - 138 IS - 14 SP - 50149 PB - Wiley AN - OPUS4-51957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Droste, Bernhard A1 - Wolff, Dietmar A1 - Bevilacqua, A. A1 - Reiche, I. A1 - Harvey, J. A1 - Hirose, M. A1 - Kumano, Y. A1 - McConnell, P. A1 - Saegusa, T. A1 - Einziger, R. ED - González-Espartero, A. T1 - Methodology for a Safety Case of a Dual Purpose Cask for Storage and Transport of Spent Fuel N2 - Spent nuclear fuel which is generated in the operation of nuclear reactors needs to be safely managed following its removal from the reactor core. On-site power reactor storage pools were designed on the assumption that after a short period of time spent nuclear fuel would be removed for reprocessing and disposal or further storage elsewhere. The amount of highly radioactive spent fuel that needs to be stored over longer periods of time is growing and additional storage capacity is required. One of the widely used options for additional storage capacity is the use of casks for dry storage of spent fuel. Among various existing dry storage concepts, several Member States are utilizing a concept of dual purpose casks (DPCs). This publication provides practical advice on the structure and contents of a DPC integrated safety case with reference to existing IAEA requirements relevant to the licensing and use of transport and storage casks for spent fuel. KW - Dual Purpose Cask KW - Spent Fuel KW - Storage KW - Transport PY - 2020 UR - https://www.iaea.org/publications/10966/methodology-for-a-safety-case-of-a-dual-purpose-cask-for-storage-and-transport-of-spent-fuel SN - 978-92-0-131620-2 SN - 1011–4289 SP - 1 EP - 109 PB - IAEA Publishing Section CY - Vienna, Austria AN - OPUS4-51962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Matzen, Melissa A1 - Marti, J. M. A1 - Onate, E. A1 - Idelsohn, S. A1 - Schartel, Bernhard T1 - Particle finite element modelling and advanced experiments on dripping V-0 polypropylene N2 - Melt flow and dripping of polymeric materials can be both beneficial and detrimental during fire. It reduces flame spread and result in extinction, as mass and heat are removed from the actual pyrolysis zone. In contrast, melt flow and dripping can provide an additional ignition source, additional process of flame spread and has the potential to start a pool fire. In the vertical UL 94 test, a well adjusted dripping behaviour of flame retarded polypropylene (PP-FR) resulted in a non-flaming dripping V-0 classification. For the polymer samples and their drops collected in UL 94, the decomposition and viscosity was investigated. Particle finite element method (PFEM) was successfully used to simulate the material behaviour in the UL 94 test and increased the understanding of the complex behaviour of polymeric materials during fire. T2 - Fire and Materials, 15th International Conference CY - San Francisco, CA, USA DA - 06.02.2017 KW - V0 dripping KW - Melt flow KW - Flammability KW - Flame retardant KW - Radical generator KW - Dripping agent KW - Polypropylene KW - Particle Finite Element Modelling PY - 2017 SP - 57 EP - 62 PB - Interscience Communication CY - Bromley, UK AN - OPUS4-39443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maenz, S. A1 - Brinkmann, O. A1 - Kunisch, E. A1 - Horbert, V. A1 - Gunella, F. A1 - Bischoff, S. A1 - Schubert, H. A1 - Sachse, A. A1 - Xin, L. A1 - Günster, Jens A1 - Illerhaus, Bernhard A1 - Jandt, K. D. A1 - Bossert, J. A1 - Kinne, R. W. A1 - Bungartz, M. T1 - Enhanced bone formation in sheep vertebral bodies after minimally invasive treatment with a novel, PLGA fiber-reinforced brushite cement. N2 - Injectable, brushite-forming calcium phosphate cements (CPC) show potential for bone replacement, but they exhibit low mechanical strength. This study tested a CPC reinforced with poly(l-lactide-co-glycolide) acid (PLGA) fibers in a minimally invasive, sheep lumbar vertebroplasty model. The study aimed to test the in vivo biocompatibility and osteogenic potential of a PLGA fiber-reinforced, brushite-forming CPC in a sheep large animal model. KW - µCT KW - Vertebral KW - PLGA cement PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S152994301631066X U6 - https://doi.org/10.1016/j.spinee.2016.11.006 SN - 1529-9430 SN - 1878-1632 VL - 17 IS - 5 SP - 709 EP - 719 PB - Elsevier Science direct AN - OPUS4-40462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Velencoso, M. M. A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Schartel, Bernhard A1 - Wurm, F. R. T1 - Molecular firefighting – How modern phosphorus chemistry can help solve the challenge of flame retardancy N2 - The ubiquity of polymeric materials in daily life Comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flameretarding polymeric materials. Phosphorus-based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus-based flame-retardants from renewable sources. KW - Flame retardant KW - Phosphorus KW - Halogen-free PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-457009 SN - 1433-7851 SN - 1521-3773 VL - 57 IS - 33 SP - 10450 EP - 10467 PB - Wiley VHC AN - OPUS4-45700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lenz, J. U. A1 - Pospiech, D. A1 - Komber, H. A1 - Korwitz, A. A1 - Kobsch, O. A1 - Paven, M. A1 - Albach, R. W. A1 - Günther, Martin A1 - Schartel, Bernhard T1 - Effective halogen-free flame-retardant additives for crosslinked rigid polyisocyanurate foams: Comparison of chemical structures N2 - The impact of phosphorus-containing flame retardants (FR) on rigid polyisocyanurate (PIR) foams is studied by systematic variation of the chemical structure of the FR, including non-NCO-reactive and NCO-reactive dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO)- and 9,10 dihydro-9-oxa-10 phosphaphenanthrene-10-oxide (DOPO)-containing compounds, among them a number of compounds not reported so far. These PIR foams are compared with PIR foams without FR and with standard FRs with respect to foam properties, thermal decomposition, and fire behavior. Although BPPO and DOPO differ by just one oxygen atom, the impact on the FR properties is very significant: when the FR is a filler or a dangling (dead) end in the PIR polymer network, DOPO is more effective than BPPO. When the FR is a subunit of a diol and it is fully incorporated in the PIR network, BPPO delivers superior results. KW - Flame retardant; KW - Dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide; BPPO KW - 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; DOPO KW - Polyisocyanurate; PIR KW - Rigid foam KW - Cone calorimeter KW - Pudovik reaction PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-567712 SN - 1996-1944 VL - 16 IS - 1 SP - 1 EP - 22 PB - MDPI CY - Basel AN - OPUS4-56771 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kinne, R. W. A1 - Gunnella, F. A1 - Kunisch, E. A1 - Heinemann, S. A1 - Nies, B. A1 - Maenz, S. A1 - Horbert, V. A1 - Illerhaus, Bernhard A1 - Huber, R. A1 - Firkowska-Boden, I. A1 - Bossert, J. A1 - Jandt, K. D. A1 - Sachse, A. A1 - Bungartz, M. A1 - Brinkmann, O. T1 - Performance of calcium phosphate cements in the augmentation of sheep vertebrae - An ex vivo study N2 - Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactideco-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2–4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young’s modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young’s modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery. KW - Sheep KW - PMMA KW - Calcium phosphate bone cement KW - Oil-based KW - Ready-to-use KW - Water-based KW - Micro-CT KW - Compressive strength KW - Young’s modulus PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-569072 SN - 1996-1944 VL - 14 IS - 14 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-56907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Turski Silva Diniz, Analice A1 - Marti, J. M. A1 - Schartel, Bernhard T1 - High Heat Resistance Can Be Deceiving: Dripping Behavior of Polyamide 4.6 in Fire N2 - Polyamide 4.6 (PA46) is a high-heat-resistant polymer, but it has no dripping resistance under fire. Three commercial grades of PA46 are investigated under UL 94 vertical fire test conditions. Their performances are discussed based on the materials’ structural, thermal, and rheological properties. PA46 presents flaming drops, whereas dripping is prevented in the flame-retarded PA46. Friction-modified PA46 has increased flaming dripping. Temperature profiles of the specimens under fire and the temperature of the drops are measured by thermocouples. A UL 94 vertical test configuration consisting of two flame applications is designed to assess the quantitative dripping behavior of the set of materials by the particle finite element method (PFEM). Polymer properties (activation energy and Arrhenius coefficient of decomposition, char yield, density, effective heat of combustion, heat of decomposition, specific heat capacity, and thermal conductivity) in addition to rheological responses in high temperatures are estimated and measured as input parameters for the simulations. The dripping behavior obtained by simulated materials corresponds with the experimental results in terms of time and drop size. A consistent picture of the interplay of the different phenomena controlling dripping under fire appears to deliver a better understanding of the role of different materials’ properties KW - Dripping KW - UL 94 KW - PFEM KW - High heat resistance KW - Polyamide 4.6 KW - Flammability PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-586015 SN - 1439-2054 SN - 1438-7492 VL - 308 IS - 10 SP - 1 EP - 11 PB - Wiley-VCH AN - OPUS4-58601 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fornacon-Wood, C. A1 - Stühler, M. R. A1 - Gallizioli, C. A1 - Manjunatha, B. R. A1 - Wachtendorf, Volker A1 - Schartel, Bernhard A1 - Plajer, A. J. T1 - Precise construction of weather-sensitive poly(ester-alt-thioesters) from phthalic thioanhydride and oxetane N2 - We report the selective ring opening copolymerisation (ROCOP) of oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K catalyst precisely yielding semi-crystalline alternating poly(esteralt- thioesters) which show improved degradability due to the thioester links in the polymer backbone. KW - Sulfur containing polymers KW - Durability KW - Weathering KW - Synthesis PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-590762 SN - 1364-548X VL - 59 IS - 76 SP - 11353 EP - 11356 PB - RSC AN - OPUS4-59076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mironov, Y.V. A1 - Shestopalov, M.A. A1 - Brylev, K.A. A1 - Yarovoi, S. S. A1 - Romanenko, G.V. A1 - Fedorov, V.E. A1 - Spies, H. A1 - Pietzsch, H.-J. A1 - Stephan, H. A1 - Geipel, G. A1 - Bernhard, G. A1 - Kraus, Werner T1 - [Re6Q7O(3,5-Me2PzH)6]Br2.3,5-Me2PzH (Q = S, Se) - New Octahedral Rhenium Cluster Complexes with Organic Ligands: Original Synthetic Approach and Unexpected Ligand Exchange in the Cluster Core KW - Rhenium KW - Cluster compounds KW - Ligand exchange KW - Organic ligands KW - Structure elucidation KW - Laser fluorescence spectroscopy PY - 2005 SN - 1434-1948 SN - 1099-0682 SP - 657 EP - 661 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-7039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, Martin A1 - Milmann, Boris A1 - Mielentz, Frank A1 - Streicher, Doreen A1 - Redmer, Bernhard A1 - Mayer, K. A1 - Langenberg, K.-J. A1 - Schickert, M. T1 - Ultrasonic Imaging Methods for Investigation of Post-tensioned Concrete Structures: A Study of Interfaces at Artificial Grouting Faults and Its Verification N2 - This paper presents the progress of successful location of grouting faults in tendon ducts with ultrasonic imaging. The examples were obtained in the research group FOR 384 funded by DFG (German Research Foundation). The co-operation of experimental research and modeling allowed imaging and identification of grouted and ungrouted areas of tendon ducts (including strands) in a large test specimen (40 m²). In addition to the criteria for indicating grouting faults in post-tensioned ducts known until now the phase evaluation of reflected ultrasonic pulses is described. Experiments and modeling of wave propagation are presented for reflections at metal plates in concrete (thickness range 0.5 mm to 40 mm) and for tendon ducts including strands. The main part of the progress was achieved by automated measurements using dry contact transducers, 3D-SAFT reconstruction including phase evaluation and modeling considering wave propagation for typical elastic parameters and exact experimental site conditions. The results for shear waves as well as for pressure waves are compared in the frequency range from 50 kHz to 120 kHz. KW - Non-destructive testing KW - Tendons KW - Prestressed concrete bridges KW - Ultrasonic echo KW - Reconstruction calculation KW - 3D-SAFT KW - Modeling (EFIT) PY - 2008 U6 - https://doi.org/10.1007/s10921-008-0033-5 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 67 EP - 82 PB - Plenum Press CY - New York, NY AN - OPUS4-17922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Knoll, Uta A1 - Schartel, Bernhard T1 - Effective halogen-free flame retardants for carbon fibre-reinforced epoxy composites N2 - DOPO-based flame retardants with tailored chemical structures are proposed for carbon fibre reinforced epoxy composites. Critical properties related to the fracture toughness are maintained, effectively allowing the use of such compounds in composites for demanding applications. KW - Fire retardancy KW - DOPO KW - Epoxy resin KW - LOI KW - UL94 PY - 2006 U6 - https://doi.org/10.1007/s10853-006-0134-4 SN - 0022-2461 SN - 1573-4803 VL - 41 IS - 15 SP - 4981 EP - 4984 PB - Springer Science + Business Media B.V. CY - New York, USA AN - OPUS4-12641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Perez, R.M. A1 - Sandler, J.K.W. A1 - Altstädt, V. A1 - Hoffmann, T. A1 - Pospiech, D. A1 - Ciesielski, M. A1 - Döring, M. A1 - Braun, Ulrike A1 - Balabanovich, Aliaksandr A1 - Schartel, Bernhard T1 - Novel phosphorus-modified polysulfone as a combined flame retardant and toughness modifier for epoxy resins N2 - A novel phosphorus-modified polysulfone (P-PSu) was employed as a combined toughness modifier and a source of flame retardancy for a DGEBA/DDS thermosetting system. In comparison to the results of a commercially available polysulfone (PSu), commonly used as a toughness modifier, the chemorheological changes during curing measured by means of temperature-modulated DSC revealed an earlier occurrence of mobility restrictions in the P-PSu-modified epoxy. A higher viscosity and secondary epoxy-modifier reactions induced a sooner vitrification of the reacting mixture; effects that effectively prevented any phase separation and morphology development in the resulting material during cure. Thus, only about a 20% increase in fracture toughness was observed in the epoxy modified with 20 wt.% of P-PSu, cured under standard conditions at 180 °C for 2 h. Blends of the phosphorus-modified and the standard polysulfone (PSu) were also prepared in various mixing ratios and were used to modify the same thermosetting system. Again, no evidence for phase separation of the P-PSu was found in the epoxy modified with the P-PSu/PSu blends cured under the selected experimental conditions. The particular microstructures formed upon curing these novel materials are attributed to a separation of PSu from a miscible P-PSu–epoxy mixture. Nevertheless, the blends of P-PSu/PSu were found to be effective toughness/flame retardancy enhancers owing to the simultaneous microstructure development and polymer interpenetration. KW - Flame retardants KW - Phosphorus-modified polysulfone KW - Fracture toughness PY - 2007 SN - 0032-3861 SN - 1873-2291 VL - 48 IS - 3 SP - 778 EP - 790 PB - Springer CY - Berlin AN - OPUS4-14515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mironov, Y.V. A1 - Brylev, K.A. A1 - Shestopalov, M.A. A1 - Yarovoi, S. S. A1 - Fedorov, V.E. A1 - Spies, H. A1 - Pietzsch, H.-J. A1 - Stephan, H. A1 - Geipel, G. A1 - Bernhard, G. A1 - Kraus, Werner T1 - Octahedral rhenium cluster complexes with organic ligands: Synthesis, structure and properties of [Re6Q8(3,5-Me2PzH)6]Br2 . 2(3,5-Me2PzH) (Q = S, Se) N2 - Two new octahedral cluster complexes – [Re6S8(3,5-Me2PzH)6]Br2 · 2(3,5-Me2PzH) (1) and [Re6Se8(3,5-Me2PzH)6]Br2 · 2(3,5-Me2PzH) (2), where 3,5-Me2PzH is 3,5-dimethylpyrazole, have been synthesized using reaction of rhenium chalcobromide complexes Cs4[Re6S8Br6] · 2H2O and Cs3[Re6Se8Br6] · H2O, respectively, with molten 3,5-dimethylpyrazole. Both compounds synthesized were characterized by X-ray single-crystal diffraction and chemical analysis, IR and luminescent spectra. KW - Synthesis KW - Crystal structure KW - Rhenium complexes KW - Octahedral clusters KW - Organic ligands PY - 2006 U6 - https://doi.org/10.1016/j.ica.2005.08.012 SN - 0020-1693 SN - 1873-3255 VL - 359 IS - 4 SP - 1129 EP - 1134 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-14489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kempel, Florian A1 - Schartel, Bernhard A1 - Hofmann-Böllinghaus, Anja A1 - Butler, K.M. A1 - Onate, E. A1 - Idelsohn, S.R. A1 - Rossi, R. A1 - Marti, J.M. T1 - Numerical simulation of polymeric materials in UL 94 test: Competition between gasification and melt flow/dripping T2 - Interflam 2010 - 12th International conference CY - Nottingham, UK DA - 2010-07-05 KW - Particle finite element method (PFEM) KW - UL 94 KW - Fire retardancy KW - PC/ABS KW - Melt flow KW - Dripping PY - 2010 SN - 978-0-9541216-5-5 N1 - Geburtsname von Hofmann-Böllinghaus, Anja: Hofmann, A. - Birth name of Hofmann-Böllinghaus, Anja: Hofmann, A. VL - 1 SP - 721 EP - 730 PB - Interscience Communications CY - London, UK AN - OPUS4-21670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kempel, Florian A1 - Schartel, Bernhard A1 - Marti, J.M. A1 - Butler, K.M. A1 - Rossi, R. A1 - Idelsohn, S.R. A1 - Onate, E. A1 - Hofmann-Böllinghaus, Anja T1 - Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion N2 - An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. KW - Melt dripping KW - UL 94 KW - Particle finite element method (PFEM) KW - Simulation KW - Bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) KW - Polytetrafluoroethylene (PTFE) KW - Bisphenol A bis(diphenyl phosphate) (BDP) PY - 2015 U6 - https://doi.org/10.1002/fam.2257 SN - 0308-0501 SN - 1099-1018 VL - 39 IS - 6 SP - 570 EP - 584 PB - Heyden CY - London AN - OPUS4-34285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Humphrey, J.K. A1 - Gibson, A.G. A1 - Hörold, Andreas A1 - Trappe, Volker A1 - Gettwert, V. T1 - Assessing the structural integrity of carbon-fibre sandwich panels in fire: Bench-scale approach N2 - The fire resistance of lightweight sandwich panels (SW) with carbon fibre/epoxy skins and a poly(methacryl imide) (PMI) foam core is investigated in compression under direct application of a severe flame (heat flux=200 kW m−2). A bench-scale test procedure was used, with the sample held vertically. The epoxy decomposition temperature was quickly exceeded, with rapid flash-over and progressive core softening and decomposition. There is a change in failure mode depending on whether the load is greater or less than 50% of the unexposed failure load, or in other words if one or two skins carry the load. At high loads, failure involved both skins with a single clear linear separation across each face. There is an inflection in the failure time relationship in the ∼50% load region, corresponding to the time taken for heat to be transmitted to the rear face, along with a change in the rear skin failure mode from separation to the formation of a plastic hinge. The integrity of the carbon front face, even with the resin burnt out, and the low thermal diffusivity of the core, both play key roles in prolonging rear face integrity, something to be borne in mind for future panel design. Intumescent coatings prolong the period before failure occurs. The ratio of times to failure with and without protection is proposed as a measure of their effectiveness. Apart from insulation properties, their adhesion and stability under severe fire impact play a key role. KW - Carbon fibres KW - Sandwich KW - Structural composites KW - Fracture KW - High-temperature properties KW - Surface treatments PY - 2019 U6 - https://doi.org/10.1016/j.compositesb.2018.11.077 SN - 1359-8368 VL - 164 SP - 82 EP - 89 PB - Elsevier AN - OPUS4-46908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -