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 DO - 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 - Zhou, F. A1 - Ma, C. A1 - Zhang, K. A1 - Chan, Yin Yam A1 - Xiao, Y. A1 - Schartel, Bernhard A1 - Döring, M. A1 - Wang, B. A1 - Hu, W. A1 - Hu, Y. T1 - Synthesis of Ethyl (Diethoxymethyl)phosphinate Derivatives and Their Flame Retardancy in Flexible Polyurethane Foam: Structure-flame Retardancy Relationships N2 - Three novel liquid ethyl (diethoxymethyl)phosphinate derivatives (EDPs) were synthesized and incorporated into flexible polyurethane foams (FPUFs). The flame retardancy of FPUFs were evaluated by limiting oxygen index (LOI), vertical burning and cone calorimetry tests, and the results indicated the structure-flame retardancy relationship of EDPs. Among these EDPs, P-(diethoxymethyl)-N-phenylphosphonamidate (EDPPA) exhibited the best flame retardant effect, methyl 3-((diethoxymethyl)(ethoxy)phosphoryl)propanoate (EDPMA) the second, and ethyl phenyl (di-ethoxymethyl)phosphonate (EDPPO) the worst. When the incorporation of EDPPA was 10 wt%, the FPUFs could self-extinguish and pass the vertical burning test. Meanwhile, the LOI value of FPUF-PA increased to 23.6% with 20 wt% loading of flame retardant. According to the investigation of volatiles during the thermal degradation of FPUFs and the morphologies of char residues after cone test, we inferred the pos- sible flame retardant mechanism. The results indicated that EDPs could release phosphorus-containing compounds in the gas phase, which would generate phosphorus-containing radicals and play the role of radical scavenger. In the condensed phase, EDPs can promote the formation of dense, intact and thermal stably char layer on the surface of FPUFs. Moreover, we found that the structure influence on flame retardancy was attributed to the atoms linked to the central phosphorus. Our results indicate that these EDPs are promising flame retardants in FPUFs that can be applied to improve the flame retardancy of FPUFs in various practical applications. KW - Ethyl (diethoxymethyl)phosphinate derivatives KW - Flame retardant KW - Flexible polyurethane foam KW - Structure-flame retardancy relationship PY - 2021 DO - https://doi.org/10.1016/j.polymdegradstab.2021.109557 SN - 0141-3910 VL - 188 SP - 109557 PB - Elsevier Ltd. AN - OPUS4-53085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pospiech, D. A1 - Fischer, O. A1 - Korwitz, A. A1 - Hoffmann, T. A1 - Köppl, T. A1 - Altstädt, V. A1 - Ciesielski, M. A1 - Döring, M. A1 - Brehme, Sven A1 - Schartel, Bernhard A1 - Vollmerhausen, D. T1 - Designed flame retardancy with phosphorus polymers N2 - Polymeric flame retardants offer the possibility to match effective flame retardancy with the requirements of new regulations. Synthesis, properties and efficiency in polymer matrices are discussed for two systems, epoxy resins as well as poly(butylene terephthalate). T2 - 25th Annual conference: Recent advances in flame retardancy of polymeric materials CY - Stamford, Connecticut, USA DA - 18.05.2014 KW - Flame retardancy KW - Phosphorus polymer KW - Poly(butylene terephthalate) KW - Epoxy resin PY - 2014 SP - 1 EP - 5 AN - OPUS4-30951 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 DO - 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 - 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 DO - 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 - Brehme, Sven A1 - Schartel, Bernhard A1 - Goebbels, Jürgen A1 - Fischer, O. A1 - Pospiech, D. A1 - Bykov, Y. A1 - Döring, M. T1 - Phosphorus polyester versus aluminium phosphinate in poly(butylene terephthalate) (PBT): Flame retardancy performance and mechanisms N2 - Pyrolysis and fire behaviour of a phosphorus polyester (PET-P-DOPO) have been investigated. The glycol ether of the hydroquinone derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was used as a reactive halogen-free flame retardant in PET-P-DOPO. PET-P-DOPO is proposed as an alternative to poly(butylene terephthalate) (PBT) with established halogen-free additives. It exhibits a high LOI (39.3%) and achieves V-0 classification in the UL 94 test. Three different mechanisms (flame inhibition, charring and a protection effect by the intumescent char) contribute to the flame retardancy in PET-P-DOPO and were quantified with respect to different fire risks. The fire load was reduced by 66% of the PBT characteristic. The reduction is the superposition of the relative reduction due to flame inhibition (factor 0.625) and charring (factor 0.545). The peak of heat release rate (pHRR) was reduced by 83% due to flame inhibition, charring and the protection properties of the char (factor 0.486). The strength of all three mechanisms is in the same order of magnitude. The intumescent multicellular structure enables the char to act as an efficient protection layer. PBT flame-retarded with aluminium diethylphosphinate was used as a benchmark to assess the performance of PET-P-DOPO absolutely, as well as versus the phosphorus content. PET-P-DOPO exhibits superior fire retardancy, in particular due to the additional prolongation of the time to ignition and increase in char yield. PET-P-DOPO is a promising alternative material for creating halogen-free flame-retarded polyesters. KW - Poly(butylene terephthalate) (PBT) KW - Fire retardancy KW - Aluminium phosphinate KW - 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) PY - 2011 DO - https://doi.org/10.1016/j.polymdegradstab.2011.01.035 SN - 0141-3910 SN - 1873-2321 VL - 96 IS - 5 SP - 875 EP - 884 PB - Applied Science Publ. CY - London AN - OPUS4-23469 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 DO - 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 - 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 DO - 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 -