TY - JOUR A1 - Krebs, N. A1 - Demleitner, M. A1 - Albuquerque, R.Q. A1 - Schartel, Bernhard A1 - Ruckdäschel, H. T1 - Bayesian Optimization of flame-retardant performance in a high-Tg epoxy resin system N2 - Polymeric materials are widely used due to their mechanical properties and cost-effectiveness, but their inherent flammability requires effective flame-retardant additives to meet safety standards. Optimizing multicomponent flame-retardant formulations is challenging due to the vast experimental space. This study applies Bayesian Optimization (BO) to optimize flame-retardant formulations in high glass transition temperature (Tg) epoxy resins. Aluminum diethyl phosphinate (AlPi) was systematically combined with three synergists: zinc stannate (ZnSt), a silicone-based additive (DowSil), and low-melting glass frits (Ceepree). BO-guided experimental design expanded from 16 initial formulations to a total of 28, minimizing the Maximum Average Rate of Heat Emission (MARHE) under the constraint of Total Smoke Production (TSP) < 17 m2 using the epsilon-constraint method. BO revealed non-linear synergistic interactions: ZnSt significantly reduced smoke production while AlPi effectively lowered heat release. The optimized formulation (BO7) achieved the lowest MARHE (122 kW/m2) while maintaining acceptable smoke levels, establishing a new Pareto front. The results demonstrate the effectiveness of BO in accelerating the development of synergistic, halogen-free flame-retardant polymer systems, offering a scalable and sustainable approach to polymer formulation design. KW - Machine learning KW - Epoxy resin KW - Bayesian optimization KW - Flame retardancy KW - Cone calorimeter PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641070 DO - https://doi.org/10.1016/j.commatsci.2025.114210 SN - 0927-0256 SN - 1879-0801 VL - 260 SP - 1 EP - 9 PB - Elsevier AN - OPUS4-64107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gleuwitz, F. Robert A1 - Battig, Alexander A1 - Schartel, Bernhard T1 - Tenebrio molitor Beetle as a “Nonvegan” Adjuvant to Flame Retardants in Tannic Acid-Based Epoxy Thermosets N2 - Material solutions that meet both circular bioeconomy policies and high technical requirements have become a matter of particular interest. In this work, a prospectively abundant proteinrich waste resource for the manufacturing of flame-retardant epoxy biocomposites, as well as for the synthesis of biobased flame retardants or adjuvants, is introduced. Different biomass fillers sourced from the cultivation of the mealworm beetle Tenebrio molitor are embedded in a bioepoxy resin cured with tannic acid and investigated regarding the fire performance of the thermosets. By means of spectroscopic and thermal analysis (attenuated total reflectance FTIR spectroscopy, thermogravimetric analysis-coupled FTIR spectroscopy, and differential scanning calorimetry), the influence of the biomass microparticles on the curing and thermal degradation behavior is evaluated. The final performance of the biocomposites is assessed based on fire testing methodology (limited oxygen index, UL-94, and cone calorimetry). Providing a high charring efficiency in the specific tannic acid-based epoxy matrix, the protein-rich adult beetle is further investigated in combination with commercial environmentally benign flame retardants in view of its potential as an adjuvant. The results highlight a char forming effect of nonvegan fillers in the presence of tannic acid, particularly during thermal decomposition, and point toward the potential of protein-based flame retardants from industrial insect rearing for future formulations. KW - Tannic acid KW - Flame retardancy KW - Sustainable KW - Epoxy resin KW - Insects PY - 2022 DO - https://doi.org/10.1021/acssuschemeng.2c00746 SN - 2168-0485 VL - 10 IS - 19 SP - 6313 EP - 6324 PB - ACS AN - OPUS4-54845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Garfias González, Karla I. A1 - Schartel, Bernhard T1 - Valorizing “non-vegan” bio-fillers: Synergists for phosphorus flame retardants in epoxy resins N2 - Sustainable, biogenic flame retardant adjuvants for epoxy resins are receiving increased focus. Zoological products like insects, bone meal, and eggshells are available in large quantities, but remain uninvestigated as functional fillers to epoxy resins, although they are potential synergists to flame retardants. The efficacy and flame retardancy of “non-vegan” additives in combination with flame retardants is investigated and the fire behavior and thermal decomposition of bio-sourced epoxy resin composites is characterized. By comparing the fire performance of composites containing flame retardants or fillers at varying loadings (5, 10, and 20%), their role as synergists that enhance the function of organophosphorus flame retardants in bio-epoxy composites is identified and quantified. Peak heat release rates were 44% lower in composites containing both filler and flame retardant versus those containing only flame retardants, and fire loads were reduced by 44% versus the pure resin, highlighting the ability of “non-vegan” fillers to function as synergists. KW - Flame retardancy KW - Synergy KW - Bio-composite KW - Epoxy resin KW - Biogenic KW - Renewable PY - 2022 DO - https://doi.org/10.1016/j.polymdegradstab.2022.109875 SN - 0141-3910 VL - 198 SP - 109875 PB - Elsevier Ltd. AN - OPUS4-54438 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 DO - 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 - 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 DO - 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 - Qiu, Y. A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Qian, L. A1 - Liu, Z. A1 - Schartel, Bernhard T1 - Improved flame retardancy by synergy between cyclotetrasiloxane and phosphaphenanthrene/triazine compounds in epoxy thermoset N2 - A siloxane compound (MVC) and a bi-group phosphaphenanthrene/triazine compound (TGD) were employed in epoxy thermosets to explore high-efficiency flame retardant systems. With only 1wt% MVC and 3wt% TGD, an epoxy thermoset passed UL 94 V-0 rating test and achieved a limiting oxygen index value of 34.0%, exhibiting an excellent flame retardant effect. The MVC/TGD system not only decreased the peak value of heat release rate and effective heat of combustion but also imparted an improved charring ability to thermosets, thereby outstandingly reducing the flammability of 1%MVC/3%TGD/EP. Compared with the fire performance of 4%TGD/EP and 4%MVC/EP, the MVC/TGD system showed an obvious flame retardant synergistic effect, mainly depending on the general improvement of flame inhibition, charring and barrier effects of the thermoset during combustion. Evolved gas analysis combinedwith condensed-phase pyrolysis product Analysis jointly revealed the details of the changed pyrolysis mode. KW - Flame retardant KW - Epoxy resin KW - Synergy KW - Siloxane KW - DOPO KW - Triazine PY - 2017 DO - https://doi.org/10.1002/pi.5466 SN - 0959-8103 SN - 1097-0126 VL - 66 IS - 12 SP - 1883 EP - 1890 PB - Wiley AN - OPUS4-42950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schartel, Bernhard T1 - Flame and fire retardancy of polymer composites used in aviation N2 - The fire behaviour of carbon fibre (CF) reinforced polymers differs in comparison to polymers. Fibres behave often inert with respect to pyrolysis, they change the melt flow and dripping behaviour, the heat absorption and transfer, the amount and properties of the fire residue and so on. Flame and fire retardancy concepts are needed not only suitable for the different fire protection goals typical for each application, but also tailored for composites. This field is illuminated by examples taken from different projects carried out in the group of the author in the recent years. The examples target on different applications through achieving reduction in reaction to fire controlling the fire risks (flammability, heat release) in the beginning and development of a fire and investigating the fire stability, when a severe flame is directly applied (key property in fully developed fires). Approaches to halogen-free flame retardancy in CF reinforced thermosets are presented as well as building up a bench and an intermediate scale testing of composites in fire applying mechanical load (up to 1 MN compression) and direct flame exposure (180 kW/m2) simultaneously. Indeed, e.g. we have investigated the fire stability of stringer reinforced shell components taken out from the fuselage of an aircraft. The understanding of fire behaviour, fire resistance, and fire retardant modes of action in composites is a promising basis for target-oriented development. The role of flame inhibition, charring, and protective layer formation is discussed. Successful concepts are presented for fire retardancy tailored for different application as well as general guidelines for future development. Different phosphorus flame retardants are proposed to achieve halogen-free flame retardancy with respect to ignition and developing fires. Different protective approaches are sketched for addressing the fire stability of composites that is the most important fire risk for the fire resistance in structural applications. T2 - 7th EASN International Conference on Innovation in European Aeronautics Research CY - Warsaw, Poland DA - 26.09.2017 KW - Composite in Fire KW - Carbon fibre reinforced composite KW - Epoxy resin KW - Stringer reinforced shells KW - Fire stability KW - Flammability KW - Sandwich panels KW - Intumescence KW - Pyrolysis KW - Flame retardant PY - 2017 AN - OPUS4-42433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rabe, Sebastian A1 - Chuenban, Yuttapong A1 - Schartel, Bernhard T1 - Exploring the Modes of Action of Phosphorus-Based Flame Retardants in Polymeric Systems N2 - Phosphorus-based flame retardants were incorporated into different, easily preparable matrices, such as polymeric thermoset resins and paraffin as a proposed model for polyolefins and investigated for their flame retardancy performance. The favored mode of action of each flame retardant was identified in each respective system and at each respective concentration. Thermogravimetric analysis was used in combination with infrared spectroscopy of the evolved gas to determine the pyrolysis behavior, residue formation and the release of phosphorus species. Forced flaming tests in the cone calorimeter provided insight into burning behavior and macroscopic residue effects. The results were put into relation to the phosphorus content to reveal correlations between phosphorus concentration in the gas phase and flame inhibition performance, as well as phosphorus concentration in the residue and condensed phase activity. Total heat evolved (fire load) and peak heat release rate were calculated based on changes in the effective heat of combustion and residue, and then compared with the measured values to address the modes of action of the flame retardants quantitatively. The quantification of flame inhibition, charring, and the protective layer effect measure the non-linear flame retardancy effects as functions of the phosphorus concentration. Overall, this screening approach using easily preparable polymer systems provides great insight into the effect of phosphorus in different flame retarded polymers, with regard to polymer structure, phosphorus concentration, and phosphorus species. KW - Flame retardants KW - Flame inhibition KW - Cone calorimeter KW - Aluminum diethyl phosphinate KW - Polyester KW - PMMA KW - Epoxy resin KW - Red phosphorus KW - BDP PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402731 DO - https://doi.org/10.3390/ma10050455 SN - 1996-1944 VL - 10 IS - 5 SP - 455, 1 EP - 455, 23 PB - MDPI AN - OPUS4-40273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Synergy in flame-retarded epoxy resin - Identification of chemical interactions by solid-state NMR N2 - The potential synergists aluminium diethylphosphinate (AlPi), boehmite (AlO(OH)) and melamine polyphosphate (MPP) were compared in flame-retardant epoxy resin (EP)/melamine poly(magnesium phosphate) (S600). The pyrolysis, the fire behaviour as well as the chemical interactions in the gas and condensed phases were investigated by various methods. Flammability was investigated by cone calorimeter and oxygen index (OI). The thermal and thermo-oxidative decomposition were studied by thermogravimetric analysis coupled with FTIR spectrometer. The special focus was on the Investigation of structural changes in the condensed phase via solid-state NMR of 27Al and 31P nuclei. By the comparison of epoxy resin with only one additive or with S600 in combination with AlPi, AlO(OH) or MPP, it was possible to calculate the synergy index. The best performance in terms of fire behaviour was observed for EP/S600/MPP with a PHRR (Peak heat release rate) of 208 kW m-2 due to slight synergy. In the case of THE (total heat evolved), clear synergy occurred for EP/S600/AlPi and EP/S600/AlO(OH). By solid-state NMR, different phosphates and aluminates were identified, indicating the chemical interactions between S600 and AlPi, AlO(OH) or MPP. The systematic multi-methodical approach yielded insight into the synergistic effects in the flame-retarded epoxy resin. KW - Synergy KW - Epoxy resin KW - Flame retardancy KW - Melamine poly(magnesium phosphate) KW - Solid-state NMR PY - 2017 DO - https://doi.org/10.1007/s10973-016-5934-4 SN - 1388-6150 SN - 1588-2926 VL - 128 IS - 1 SP - 141 EP - 153 PB - Springer AN - OPUS4-39298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, M. S. S. A1 - Schartel, Bernhard A1 - Magalhães, F. D. A1 - Pereira, C. M. C. T1 - The effect of traditional flame retardants, nanoclays and carbon nanotubes in the fire performance of epoxy resin composites N2 - The effectiveness of distinct fillers, from micro to nano-size scaled, on the fire behaviour of an epoxy resin and its carbon fibre reinforced composites was assessed by cone calorimetry. The performance was compared not only regarding the reaction to fire performance, but also in terms of thermal stability, glass transition temperature and microstructure. Regarding the fire reaction behaviour of nanofilled epoxy resin, anionic nanoclays and thermally oxidized carbon nanotubes showed the best results, in agreement with more compact chars formed on the surface of the burning polymer. For carbon fibre reinforced composite plates, the cone calorimeter results of modified resin samples did not show significant improvements on the heat release rate curves. Poorly dispersed fillers in the resin additionally caused reductions on the glass transition temperature of the composite materials. KW - Epoxy resin KW - Carbon fibre reinforced composite KW - Nanoclays KW - Carbon nanotubes KW - Flame retardants PY - 2017 DO - https://doi.org/10.1002/fam.2370 SN - 1099-1018 SN - 0308-0501 VL - 41 IS - 2 SP - 111 EP - 130 PB - Wiley & Sons, Ltd. AN - OPUS4-39085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, S. A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Qian, Lijun A1 - Dong, Y. A1 - Schartel, Bernhard T1 - Enhanced flame-retardant effect of montmorillonite/phosphaphenanthrene compound in an epoxy thermoset N2 - A phosphaphenanthrene and triazinetrione group containing flame retardant (TAD) is combined with organically modified montmorillonite (OMMT) in epoxy resin thermosets (EP) to improve the performance of the flame-retardant system. When only 1 wt% OMMT/4 wt% TAD is introduced into the EP, the limited oxygen index (LOI) rises from 26% to 36.9% and a V-0 rating is achieved in a UL 94 test. The decomposition and pyrolysis products in the gas phase and condensed phase were characterized using thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR). The influence on the decomposition of EP, such as the increase in char yield, is limited with the incorporation of OMMT; a large amount of the phosphorus is released into the gas phase. The flame-retardant effect evaluation based on cone calorimeter data testified that OMMT improves the protective-barrier effect of the fire residue of OMMT/TAD/EP on the macroscopic scale, while TAD mainly causes flame inhibition. The fire residues showed a corresponding macroscopic appearance (digital photo) and microstructure (scanning electron microscope [SEM] results). The protective barrier effect of OMMT and the flame-inhibition effect of TAD combined to exert a superior flame-retardant effect, resulting in sufficient flame-retardant performance of OMMT/TAD/EP KW - Flame retardant KW - Nanocomposite KW - DOPO KW - Thermoset KW - Epoxy resin KW - TG-FTIR PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388865 DO - https://doi.org/10.1039/c6ra25070j SN - 2046-2069 VL - 7 IS - 2 SP - 720 EP - 728 AN - OPUS4-38886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Patrick A1 - Morys, Michael A1 - Sut, Aleksandra A1 - Jäger, Christian A1 - Illerhaus, Bernhard A1 - Schartel, Bernhard T1 - Melamine poly(zinc phosphate) as flame retardant in epoxy resin: Decomposition pathways, molecular mechanisms and morphology of fire residues N2 - Synergistic multicomponent systems containing melamine poly(metal phosphate)s have been recently proposed as flame retardants. This work focuses on the decomposition pathways, molecular mechanisms and morphology of the fire residues of epoxy resin (EP) flame retarded with melamine poly(zinc phosphate) (MPZnP) to explain the modes of action and synergistic effects with selected synergists (melamine polyphosphate (MPP) and AlO(OH), respectively). The total load of flame retardants was always 20 wt.%. The decomposition pathways were investigated in detail via thermogravimetric Analysis coupled with Fourier transform infrared spectroscopy. The fire residues were investigated via elemental analysis und solid-state nuclear magnetic resonance spectroscopy. The morphology of intumescent fire residues was investigated via micro-computed tomography and scanning electron microscopy. EP + (MPZnP + MPP) formed a highly voluminous residue that showed structural features of both EP + MPZnP and EP + MPP, resulting in a highly effective protection layer. EP + (MPZnP + AlO(OH)) preserved the entire quantity of phosphorus content during combustion due to the Formation of Zn₂P₂O₇ and AlPO₄. KW - Melamine poly(metal phosphate) KW - Flame retardancy KW - Epoxy resin KW - Solid-state NMR KW - Micro-computed tomography KW - Fire residue PY - 2016 DO - https://doi.org/10.1016/j.polymdegradstab.2016.06.023 SN - 0141-3910 VL - 130 SP - 307 EP - 319 PB - Elsevier AN - OPUS4-36863 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 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Kleemeier, M. A1 - Hartwig, A. T1 - Flammability of layered silicate epoxy nanocomposites combined with low-melting inorganic ceepree glass N2 - Tetraphenylphosphonium modified layered silicate epoxy nanocomposite (EP/TPPMMT) combined with low-melting silicate glass, Ceepree (CP) is investigated by thermal analysis, flammability tests and cone calorimeter at different heat fluxes. Adding CP and TPPMMT does not change the pyrolysis apart from increasing inorganic residue. The total heat evolved (THE) is changed insignificantly, as neither relevant additional carbonaceous charring nor flame inhibition occurs. However, flame retardancy is clearly observed due to an inorganic-carbonaceous surface protection layer. The peak heat released rate (PHRR) is reduced by around 32–42% when 5 wt% TPPMMT is added, and 51–63% when 10 wt% CP is added. PHRR reduction less than expected is observed when both additives are combined. The reduction is greater than that achieved by using TPPMMT but less than when only CP is used. The morphology of fire residue is investigated by scanning electron microscope on different length scales and turns out to be the key to understanding the efficiency of flame retardancy. The fire residue of EP/CP shows a layered structure, whereas separated columns limit the barrier properties for EP/5%TPPMMT on the micrometer scale. Columns dominating the fire residue structure of EP/5%TPPMMT/10%CP deteriorate the fire retardancy, whereas a more integral structure at the top of the residue causes the improvement over EP/5%TPPMMT. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers KW - Flame retardancy KW - Nanocomposites KW - Low melting glasses KW - Epoxy resin KW - Ceepree PY - 2012 DO - https://doi.org/10.1002/pen.22111 SN - 0032-3888 SN - 1548-2634 VL - 52 IS - 3 SP - 507 EP - 517 PB - Wiley CY - Hoboken, NY AN - OPUS4-25590 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Yu, D. A1 - Kleemeier, M. A1 - Hartwig, A. T1 - Synergistic fire retardancy in layered-silicate nanocomposite combined with low-melting phenysiloxane glass N2 - Tetraphenyl phosphonium-modified layered silicate (LS) and low-melting phenylsiloxane glass (G) are combined for more efficient halogen-free flame retardancy in epoxy resin (EP_LSG). Particularly, the peak heat release rate (PHRR) is decreased (by up to 60%), but levels off at additive concentrations ≥10 wt%. The performance of EP_LSG is compared to EP_LS and EP_G assuming an absolute and a relative flame retardancy effect, respectively, and based on the same amount of each filler and, alternatively, with EP_G containing the same overall amount of filler. EP_LSG behaves close to superposition but shows a strong tendency toward synergism due to a superior structural integrity of the fire residues. Apart from LS, adding G in particular is a promising approach when its content is ≤5 wt%, as is LSG for ≥10 wt%. KW - Low-melting glass KW - Layered silicate KW - Flame retardancy KW - Nanocomposites KW - Epoxy resin PY - 2012 DO - https://doi.org/10.1177/0734904111422417 SN - 0734-9041 SN - 1530-8049 VL - 30 IS - 1 SP - 69 EP - 87 PB - Sage CY - London AN - OPUS4-25359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Weiß, André A1 - Sturm, Heinz A1 - Kleemeier, M. A1 - Hartwig, A. A1 - Vogt, C. A1 - Fischer, R.X. T1 - Layered silicate epoxy nanocomposites: formation of the inorganic-carbonaceous fire protection layer N2 - The layered silicate (LS) modification and processing parameters applied control the morphology of the LS/polymer composites. Here, increasing the surface area of the LS particles by using alternative drying processes increases dispersion towards a more typical nanocomposite morphology, which is a basic requirement for promising flame retardancy. Nevertheless, the morphology at room temperature does not act itself with respect to flame retardancy, but serves as a prerequisite for the formation of an efficient surface protection layer during pyrolysis. The formation of this residue layer was addressed experimentally for the actual pyrolysis region of a burning nanocomposite and thus our results are valid without any assumptions or compromises on the time period, dimension, surrounding atmosphere or temperature. The formation of the inorganic-carbonaceous residue is influenced by bubbling, migration, reorientation, agglomeration, ablation, and perhaps also delamination induced thermally and by decomposition, whereas true sintering of the inorganic particles was ruled out as an important mechanism. Multiple, quite different mechanisms are relevant during the formation of the residue, and the importance of each mechanism probably differs from one nanocomposite system to another. The main fire protection effect of the surface layer in polymer nanocomposites based on non-charring or nearly non-charring polymers is the increase in surface temperature, resulting in a substantial increase in reradiated heat flux (heat shielding). KW - Nanocomposite KW - Fire retardancy KW - Epoxy resin KW - Fire behavior KW - Flammability PY - 2011 DO - https://doi.org/10.1002/pat.1644 SN - 1042-7147 SN - 1099-1581 VL - 22 IS - 12 SP - 1581 EP - 1592 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-24916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, D. A1 - Kleemeier, M. A1 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Liu, W.Q. A1 - Hartwig, A. T1 - Phosphorus and silicon containing low-melting organic-inorganic glasses improve flame retardancy of epoxy/clay composites N2 - New low-melting organic–inorganic glassy polymers containing phosphorus and silicon are synthesized by the reaction between phenylphosphonic acid and methyltrichlorosilane or methyltriethoxysilane. They possess both low-softening points and high onset decomposition temperatures, which are favorable for preparing flame retardant composites. Although the glass by itself is sensitive to water, the composites are not significantly affected in that way. For glass/clay/epoxy composites glass transition temperature (Tg) as well as storage modulus increase with the glass amount. The glasses improve flame retardancy significantly due to flame inhibition and the formation of fire residue working as protection layer during burning. The total heat evolved is reduced by 23–28% for using 5–15 wt.% glass and the maximum HRR even by 58–48%. The latter effect decreases with increasing glass amount due to an adulterate residue deformation. The combination of glass and clay is proposed as a possible route to enhance flame retardancy. KW - Clay KW - Epoxy resin KW - Flame retardancy KW - Organic-inorganic polymer KW - Low-melting glass PY - 2011 DO - https://doi.org/10.1002/mame.201100014 SN - 1438-7492 SN - 1439-2054 VL - 296 IS - 10 SP - 952 EP - 964 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-24516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, D. A1 - Kleemeier, M. A1 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Liu, W.Q. A1 - Hartwig, A. T1 - The absence of size- dependency in flame retarded composites containing low-melting organic-inorganic glass and clay: Comparison between micro- and nanocomposites N2 - Due to optimised processing of epoxy based composite materials containing a low-melting organic–inorganic glass together with an organo clay, the size of the glass particles could be successfully reduced. Thus truly nano-dispersed composites were obtained, with glass particles in the range of 10 nm to 200 nm. The small particle size allowed efficient interaction of glass particles and organo clay layers. The flame retardancy as well as the thermo-mechanical properties were tested, and the results showed that the low-melting glass led to a remarkable reduction of peak heat release rate by forming an enhanced barrier layer. Nevertheless no further improvement could be achieved by lowering the particle size to the nanometre region. For good flame retardancy a microdispersion of the low-melting glass was already sufficient. KW - Epoxy resin KW - Nanocomposites KW - Low-melting glass KW - Clay KW - Flame retardancy PY - 2011 DO - https://doi.org/10.1016/j.polymdegradstab.2011.06.003 SN - 0141-3910 SN - 1873-2321 VL - 96 IS - 9 SP - 1616 EP - 1624 PB - Elsevier Ltd. CY - London AN - OPUS4-24211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yu, D. A1 - Kleemeier, M. A1 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Liu, W.Q. A1 - Hartwig, A. T1 - A low melting organic-inorganic glass and its effect on flame retardancy of clay/epoxy composites N2 - A low-melting organic-inorganic glass with a high molecular weight soluble in solvents was synthesized by hydrolytic polycondensation of phenyltriethoxysilane followed by a subsequent heat treatment. Softening point and thermostability were strongly increased after heat treatment. The composites of glass/epoxy and glass/clay/epoxy were studied with respect to their thermal properties, fire behavior and mechanical properties. Heat release rate as measured by cone calorimetry was remarkably reduced in the presence of glass, relative to neat epoxy resin and polymer/clay composites. The combination of glass and clay is a promising approach. It showed mainly superposition and even synergistic effects in some fire properties for higher filler concentrations due to the formation of an enhanced barrier. The structure of residue was investigated by transmission electron microscopy (TEM). KW - Low-melting glass KW - Clay KW - Epoxy resin PY - 2011 DO - https://doi.org/10.1016/j.polymer.2011.03.033 SN - 0032-3861 SN - 1873-2291 VL - 52 IS - 10 SP - 2120 EP - 2131 PB - Elsevier Ltd. AN - OPUS4-23858 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 - 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 - 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 - 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 DO - 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 - 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 - TY - JOUR A1 - Schartel, Bernhard A1 - Knoll, Uta A1 - Hartwig, A. A1 - Pütz, D. T1 - Phosphonium-modified layered silicate epoxy resins nanocomposites and their combinations with ATH and organo-phosphorus fire retardants N2 - Phosphonium-modified layered silicate epoxy resin nanocomposites were evaluated by testing the thermal/thermo-mechanical properties [differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), torsional pendulum, Sharpy toughness], flammability (limiting oxygen index LOI) and fire behavior (cone calorimeter with different irradiations). The morphology of the composites was determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The drying conditions of phosphonium-modified layered silicate were varied in order to improve the nanocomposite formation and properties. The results were compared with using a commercial ammonium-modified montmorillonite. Enhanced nanocomposite formation was found for the commercial systems due to the amount of excess surfactant, but this effect was overcompensated through the advanced morphology of the phosphonium-modified systems. Several fire retardancy mechanisms and their specific influence on the different fire properties, such as ignitability, flammability, flame spread, total heat release (fire load), and the production of CO and smoke were discussed comprehensively. The main mechanism of layered silicate is a barrier formation influencing the flame spread in developing fires. Several minor mechanisms are significant, but important fire properties such as flammability or fire load are hardly influenced. Hence combinations with aluminum hydroxide and organo-phosphorus flame retardants were evaluated. The combination with aluminum hydroxide was a promising approach since it shows superposition in properties such as the fire load and only in some properties very little antagonism. The combination with an organo-phosphorus flame retardant disillusions, since it was characterized mainly by antagonism. KW - Flame retardance KW - Nanocomposites KW - Organoclay KW - Epoxy resin KW - Cone calorimeter PY - 2006 DO - https://doi.org/10.1002/pat.686 SN - 1042-7147 SN - 1099-1581 VL - 17 IS - 4 SP - 281 EP - 293 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-12519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -