TY - JOUR A1 - Gallo, Emanuela A1 - Fan, Z. A1 - Schartel, Bernhard A1 - Greiner, A. T1 - Electrospun nanofiber mats coating - new route to flame retardancy N2 - A novel route toward halogen-free fire retardancy of polymers through innovative surface coating is described. Nanofiber mats based on polyimide are deposited on PA66 through electrospinning. Scanning electron microscopy is used to characterize the nanofibers. Cone calorimeter tests were performed to evaluate the fire performance. Because of their low thermal conductivity, electrospun nanofiber mats act not only as sacrificial layers but also as a protective surface that delays ignition. The effect is influenced by the fiber diameters and the imidization. KW - Electrospinning KW - Polyimide KW - Nanofibers KW - Fire retardancy PY - 2011 DO - https://doi.org/10.1002/pat.1994 SN - 1042-7147 SN - 1099-1581 VL - 22 IS - 7 SP - 1205 EP - 1210 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-24093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Guang Mei A1 - Schartel, Bernhard A1 - Bahr, Horst A1 - Kleemeier, M. A1 - Yu, D. A1 - Hartwig, A. T1 - Experimental and quantitative assessment of flame retardancy by the shielding effect in layered silicate epoxy nanocomposites N2 - A quantitative experimental assessment of flame retardancy by the heat shielding in epoxy layered silicate nanocomposite (EP/TPPMMT) is presented. Online heat flux measurements and temperature monitoring within the specimen are performed during the burning in the cone calorimeter. For EP the surface layer equals a pyrolysis front. The reradiation by the hot surface corresponds to the fourth power of the pyrolysis temperature. The surface reradiation (around 10 kW m-2) is thus fairly invariable over burning time and different external heat fluxes. Further, the thermal feedback of the flame is approximated to 20 kW m-2 for both EP and EP/TPPMMT and invariable over different irradiations. Thus the net heat fluxes transformed to the fuel release rate within the pyrolysis front of EP are increased to 45–80 kW m-2 when irradiations of 35–70 kW m-2 are applied. For a residue-forming EP/TPPMMT the surface temperature and thus the reradiation (42–68 kW m-2) crucially increases compared to EP and with increasing irradiation. The net heat fluxes are reduced to 13–22 kW m-2 accordingly. This quantitative assessment of the heat shielding in EP/TPPMMT goes along with proportional and consistent improvement in the fire performance, such as the pyrolysis front velocity, the heat release rate (HRR) characteristics such as averaged and quasi-steady-state HRR and the peak HRR (PHRR). The heat shielding is proven to be the only major flame retardancy effect occurring in nanocomposites based on non-charring polymers. KW - Nanocomposites KW - Heat shielding KW - Flame retardancy KW - Shielding effect PY - 2012 DO - https://doi.org/10.1016/j.combustflame.2012.07.003 SN - 0010-2180 SN - 1556-2921 VL - 159 IS - 12 SP - 3616 EP - 3623 PB - Elsevier CY - New York, NY AN - OPUS4-26841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shabir Mahr, Muhammad A1 - Hübert, Thomas A1 - Schartel, Bernhard A1 - Bahr, Horst A1 - Sabel, Martin A1 - Militz, H. T1 - Fire retardancy effects in single and double layered sol-gel derived TiO2 and SiO2-wood composites N2 - Sol–gel derived TiO2 and SiO2-wood inorganic composites are prepared by direct vacuum infiltration of silicon and titanium alkoxide based precursors in pine sapwood in one or two cycles followed by a controlled thermal curing process. The resulting flame retardancy effect is investigated under two different fire scenarios using cone calorimetry and oxygen index (LOI). Heat release rates (HRR) especially the values for the second peak, are reduced moderately for all single layered composites. This effect is more pronounced for double layered composites where HRR was reduced up to 40 % showing flame retardancy potential in developing fires. Beside this, smoke release was lowered up to 72 % indicating that these systems had less fire hazards compared to untreated wood, whereas no meaningful improvement is realized in terms of fire load (total heat evolved) and initial HRR increase. However impressively, the LOI of the composites were increased up to 41 vol% in comparison to 23 vol% for untreated wood displaying a remarkable flame retardancy against reaction to a small flame. An approximate linear interdependence among the fire properties and the material loading as well as fire residue was observed. A residual protection layer mechanism is proposed improving the residue properties for the investigated composites. KW - Wood KW - Sol-gel KW - Composite materials KW - Cone calorimeter KW - Fire retardance KW - Flammability PY - 2012 DO - https://doi.org/10.1007/s10971-012-2877-5 SN - 0928-0707 SN - 1573-4846 VL - 64 IS - 2 SP - 452 EP - 464 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-27618 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 - Bier, A.K. A1 - Bognitzki, M. A1 - Schmidt, A. A1 - Greiner, A. A1 - Gallo, Emanuela A1 - Klack, Patrick A1 - Schartel, Bernhard T1 - Synthesis, properties, and processing of new siloxane-substituted poly(p-xylylene) via CVD N2 - The synthesis of a disiloxane-functionalized [2.2]paracyclophane and its polymerization to the corresponding siloxane-substituted poly(p-xylylene) via chemical vapor deposition (CVD) has been described. Because of the enhanced solubility of the siloxane substituted poly(p-xylylene) analysis of the molecular structure by NMR, molecular weight, and polydispersity by gel permeation chromatography (GPC), and processing by film casting as well as nanofiber formation by electrospinning was possible. Structural isomers were found by NMR which was expected due to the isomeric mixture of the precursor. High molecular weights at moderate polydispersities were found by GPC which was unexpected for a vapor phase deposition polymerization. The amorphous morphology in combination with a low glass transition temperature led to high elongation at break for the siloxane substituted poly(p-xylylene). Significant difference for the wetting versus water was found for as-deposited films, solution cast films, and nanofibers obtained by electrospinning with contact angles up to 135° close to superhydrophobic behavior. KW - Poly(p-xylylene) KW - Siloxane functionalized PPX KW - Chemical vapor deposition KW - Difunctionalized [2.2]paracyclophanes KW - Gorham process PY - 2012 DO - https://doi.org/10.1021/ma2021369 SN - 0024-9297 SN - 1520-5835 VL - 45 IS - 2 SP - 633 EP - 639 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lorenzetti, A. A1 - Modesti, M. A1 - Gallo, Emanuela A1 - Schartel, Bernhard A1 - Besco, S. A1 - Roso, M. T1 - Synthesis of phosphinated polyurethane foams with improved fire behaviour N2 - Both alkylphosphinates and inorganic phosphinates (based on sodium, calcium, magnesium or zinc) have been recently proposed as flame retardants for polyesters, polyamides and polyurethane foams as well. The main aim of this work was to compare the flame retardant effectiveness of inorganic (already proofed in PU foams) and organic phosphinates in PU foams which have never been used in polyurethane (PU) foams. The thermal stability in nitrogen and air as well as limiting oxygen index and cone calorimeter behaviour have been studied to assess the effectiveness of such flame retardants in PU foams. The results obtained showed that both inorganic and organic phosphinates are effective in enhancing fire behaviour of PU foams since they improve thermal stability, LOI and fire performance. Cone calorimetry highlighted the flame inhibition action in the gas phase due to the release of phosphorus-containing molecules. The better results obtained for inorganic phosphinate are probably related to the better quality of the char layer developed during burning, but may also be related to the higher phosphorus content of such flame retardant with respect the other ones. It was also verified that both inorganic and organic phosphinate containing N-synergic compound showed a fuel dilution effect, deriving from water and/or ammonia release in the gas phase. KW - Phosphinate KW - Polyurethane foam KW - Flame retardancy KW - Fire behaviour PY - 2012 DO - https://doi.org/10.1016/j.polymdegradstab.2012.07.026 SN - 0141-3910 SN - 1873-2321 VL - 97 IS - 11 SP - 2364 EP - 2369 PB - Applied Science Publ. CY - London AN - OPUS4-26735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shabir Mahr, Muhammad A1 - Hübert, Thomas A1 - Sabel, Martin A1 - Schartel, Bernhard A1 - Bahr, Horst A1 - Militz, H. T1 - Fire retardancy of sol-gel derived titania wood-inorganic composites N2 - Sol–gel technology was applied in tailoring novel wood-made-inorganic composites with improved thermal and fire properties. In practice, composites materials were prepared by impregnating pine sapwood wood with nano-scaled precursor solutions derived from titanium(IV) isopropoxide followed by a thermal curing process. Thermal and fire properties were evaluated by thermal analysis and cone calorimetry, whereas flammability was specified by oxygen index (LOI) and UL 94 test. Peak heat release rates were moderately reduced indicating fire retardance potential in terms of flame spread attributed to the appropriate protection layer action of the titania-based depositions. LOI (oxygen index) values of these composites were increased up to 38 vol.% in comparison to 23 vol.% for untreated wood. The flame retardancy performance depends on the fire scenario and is strongly influenced by wood loading and crackfree deposition of the titania layers inside the composite. PY - 2012 DO - https://doi.org/10.1007/s10853-012-6628-3 SN - 0022-2461 SN - 1573-4803 VL - 47 IS - 19 SP - 6849 EP - 6861 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-26235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard T1 - Towards evidence-based development of flame retarded polymers T2 - 243rd National ACS meeting - Spring 2012 CY - San Diego, CA, USA DA - 2012-03-25 KW - Flame retardancy KW - Halogen-free KW - Flame retardancy mechanism KW - Fire property assessment PY - 2012 SN - 978-0-8412-2727-9 SN - 1550-6703 N1 - Serientitel: PMSE Preprints – Series title: PMSE Preprints VL - 243 SP - 38-PMSE PB - Amer Chemical SOC CY - Washington, USA AN - OPUS4-26381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Heinz A1 - Schartel, Bernhard A1 - Weiß, André A1 - Braun, Ulrike T1 - SEM/EDX: Advanced investigation of structured fire residues and residue formation N2 - Heterogeneous, gradual or structured morphology of fire residues plays an important role in fire retardancy of polymers. A scanning electron microscope with an attached energy dispersive X-ray spectrometer (SEM/EDX) is highlighted as a powerful tool for the advanced characterization of such complex fire residues, since it offers high resolution in combination with both good depth of field and analysis of chemical composition. Two examples are presented: First, comprehensive SEM/EDX investigation on a complex structured fire residue of glass fibre reinforced polyamide 6,6 (PA 66-GF) flame retarded by diethylaluminium phosphinate, melamine polyphosphate and some zinc borate. A multilayered surface crust (thickness ~ 24 µm) covers a rather hollow area stabilized by GF glued together. The resulting efficient thermal insulation results in self-extinguishing before pyrolysis is completed, even under forced-flaming combustion. Second, sophisticated, quasi online SEM/EDX imaging of the formation of residual protection layer in layered silicate epoxy resin nanocomposites (LSEC). Burning specimens were quenched in liquid nitrogen for subsequent analyses. Different zones were distinguished in the condensed phase characterized by distinct processes such as melting and ablation of organic material, as well as agglomeration, depletion, exfoliation and reorientation of the LS. KW - Fire residue KW - SEM/EDX KW - Fire retardancy KW - PA 66 KW - Layered silicate KW - Diethylaluminium phosphinate PY - 2012 DO - https://doi.org/10.1016/j.polymertesting.2012.03.005 SN - 0142-9418 VL - 31 IS - 5 SP - 606 EP - 619 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-25802 LA - eng 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 - Naumann, Maurice T1 - Structural integrity of sandwich structures in fire: an intermediate-scale approach N2 - A test set-up in intermediate scale was conceived to investigate the structural integrity of materials under fire. The task was to develop a realistic test scenario targeting component-like behaviour. Carbon-fibre-reinforced sandwich specimens (500 X 500 X 20 mm) were used to examine failure mechanisms, times to failure and critical failure loads under compression. Fire tests were performed with fully developed fire applied to one side of the specimen by an oil burner. In a first test series, the applied load was varied, but the fully developed fire remained unchanged. In general, times to failure were short. Decreased load levels resulted in prolonged times to failure and led to a different failure mechanism. Results obtained in the test series were compared with a bench-scale study (150 X 150 X 20 mm) investigating identical material. The comparison clearly revealed the influence of size on the time to failure and the load-bearing capacity. KW - Fire testing KW - Structural integrity KW - Carbon-fibre-reinforced plastics KW - Fully developed fire KW - Composites PY - 2013 DO - https://doi.org/10.1080/15685543.2013.816620 SN - 0927-6440 SN - 1568-5543 VL - 20 IS - 9 (Special Issue: ECCM15: Part 3) SP - 741 EP - 759 PB - VSP CY - Zeist AN - OPUS4-29647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lorenzetti, A. A1 - Besco, S. A1 - Hrelja, D. A1 - Roso, M. A1 - Gallo, Emanuela A1 - Schartel, Bernhard A1 - Modesti, M. T1 - Phosphinates and layered silicates in charring polymers: The flame retardancy action in polyurethane foams N2 - Nanocomposites of a charring polymer (like polyurethane foam) filled with aluminum phosphinate (AlPi) with or without melamine cyanurate (MelCy) have been prepared by microwave processing and their thermal stability and fire behavior have been studied. Results on the interaction between flame retardants and layered silicates were provided as well as detailed investigation of the char strength, which has been carried out using a suitably developed method based on dynamic-mechanic analysis. Generally, the thermo-oxidative stability in presence of layered silicates was higher than the counterparts even if an additive rather than synergic effect took place; however, in some cases the interaction between clays and phosphinate led to a significant decrease of weight residue. In nitrogen the residue amounts were about the same but a higher amount of phosphorus was retained in the solid phase in presence of clays. Cone calorimeter results showed that the use of phosphinates led to a decrease of the PHRR; further addition of clays did not reduce the PHRR owing to the worse quality of char layer as demonstrated by the char strength test. However, it has been shown that the partial substitution of aluminum phosphinate with melamine cyanurate gave improved results: the AlPi–MelCy filled foams showed similar pHRR and THE but lower TSR and higher char strength than AlPi filled foams. It was also confirmed that phosphinate acted by flame inhibition but its action was depressed by the use of nanoclays owing to their interaction. KW - Phosphinate KW - Nanocomposite KW - Polyurethane KW - Interaction KW - Flame retardant PY - 2013 DO - https://doi.org/10.1016/j.polymdegradstab.2013.08.002 SN - 0141-3910 SN - 1873-2321 VL - 98 IS - 11 SP - 2366 EP - 2374 PB - Applied Science Publ. CY - London AN - OPUS4-29281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dittrich, Bettina A1 - Wartig, K.-A. A1 - Hofmann, D. A1 - Mülhaupt, R. A1 - Schartel, Bernhard T1 - Carbon black, multiwall carbon nanotubes, expanded graphite and functionalized graphene flame retarded polypropylene nanocomposites N2 - Herein, we examine the influence of adding functionalized graphene (FG), distinct expanded graphites and carbon nanofillers such as carbon black and multiwall carbon nanotubes on mechanical properties, morphology, pyrolysis, response to small flame and burning behavior of a V-2 classified flame-retarded polypropylene (PP). Among carbon fillers, FG and multilayer graphene (MLG) containing fewer than 10 layers are very effectively dispersed during twin-screw extrusion and account for enhanced matrix reinforcement. In contrast to the other fillers, no large agglomerates are detected for PP-FR/FG and PP-FR/MLG, as verified by electron microscopy. Adding FG to flame-retardant PP prevents dripping due to reduced flow at low shear rates and shifts the onset of thermal decomposition to temperatures 40°C higher. The increase in the onset temperature correlates with the increasing specific surface areas (BET) of the layered carbon fillers. The reduction of the peak heat release rate by 76% is attributed to the formation of effective protection layers during combustion. The addition of layered carbon nanoparticles lowers the time to ignition. The presence of carbon does not change the composition of the evolved pyrolysis gases, as determined by thermogravimetric analysis combined with online Fourier-transformed infrared measurements. FG and well-exfoliated MLG are superior additives with respect to spherical and tubular carbon nanomaterials. KW - Graphene KW - Flame retardancy KW - Nanocomposites KW - Polypropylene KW - Carbon nanoparticles PY - 2013 DO - https://doi.org/10.1002/pat.3165 SN - 1042-7147 SN - 1099-1581 VL - 24 IS - 10 SP - 916 EP - 926 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-29337 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 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 - Pappalardo, Salvatore A1 - Russo, Pietro A1 - Acierno, Domenico A1 - Rabe, Sebastian A1 - Schartel, Bernhard T1 - The synergistic effect of organically modified sepiolite in intumescent flame retardant polypropylene N2 - The pyrolysis, flammability and fire behavior of polypropylene (PP) containing an intumescent flame retardant and sepiolite nanoparticles were investigated by performing thermogravimetry, oxygen index (LOI), UL-94, and cone calorimeter tests. The combination of 0.5 wt% of premodified sepiolite (OSEP) with 12 wt% of a commercial intumescent flame retardant showed a clear synergy in LOI, UL-94 ranking and peak heat release rate. The ternary formulation achieved a V-0 classification and, consequently, allowed a reduction in the amount of flame retardant necessary to achieve this result. Whereas OSEP and pristine sepiolite nanoparticles (SEP) affect the performance in PP nanocomposites quite similarly, OSEP outperformed SEP in the combination with intumescent flame retardant. The cone calorimeter results and dynamic rheological measurements confirmed the synergistic effect between the nanofiller and the flame retardant resulting from the improved properties of the residual protective layer. KW - Polypropylene KW - Intumescent flame retardant KW - Sepiolite KW - Cone calorimetry KW - Low oxygen index PY - 2016 DO - https://doi.org/10.1016/j.eurpolymj.2016.01.041 SN - 0014-3057 VL - 76 SP - 196 EP - 207 PB - Elsevier AN - OPUS4-35854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Patrick A1 - Schartel, Bernhard T1 - Melamine poly(metal phosphates) as flame retardant in epoxy resin: Performance, modes of action, and synergy N2 - Melamine poly(metal phosphates) (MPMeP) are halogen-free flame retardants commercialized under the brand Name Safire. Melamine poly(aluminum phosphate) (MPAlP), melamine poly(zinc phosphate) (MPZnP), and melamine poly(Magnesium phosphate) (MPMgP) were compared in an epoxy resin (EP). The thermal decomposition, flammability, burning behavior, and glass transition temperature were investigated using thermogravimetric analysis, pyrolysis combustion flow calorimeter, UL 94 testing, cone calorimeter, and differential scanning calorimetry. While the materials exhibited similarities in their pyrolysis, EP+MPZnP and EP+MPMgP showed better fire behavior than EP+MPAlP due to superior protective properties of the fire residues. Maintaining the 20 wt % loading, MPZnP was combined with various other flame retardants. A synergistic effect was evident for melamine polyphosphate (MPP), boehmite, and a derivative of 6H-Dibenzo[c,e][1,2]oxaphosphinine-6-oxide. The best overall performance was observed for EP+(MPZnP+MPP) because of the best protection effectiveness of the fire residue. EP +(MPZnP+MPP) achieved V1/V0 in UL 94, and an 80% reduction in the peak heat release rate. This study evaluates the efficiency of MPMeP in EP, alone and in combination with other flame retardants. MPMeP is a suitable flame retardant for epoxy resin, depending on its kind and synergists. KW - flame retardance KW - thermogravimetric analysis KW - thermosets PY - 2016 DO - https://doi.org/10.1002/APP.43549 SN - 0021-8995 SN - 1097-4628 VL - 133 IS - 24 SP - 43549 PB - Wiley AN - OPUS4-35855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hörold, Andreas A1 - Schartel, Bernhard A1 - Trappe, Volker A1 - Gettwert, V. A1 - Korzen, Manfred T1 - Protecting the structural integrity of composites in fire: Intumescent coatings in the intermediate scale N2 - The fire behaviour of light-weight material used in structural applications is regarded as the main challenge to be solved for mass transportation. The task is to perform realistic experiments, including a mechanical test scenario under fully developed fires, to improve the material's reliability in structural applications. Our approach utilises an intermediate-scale test set-up (specimen size 500 × 500 mm) to apply realistic compressive loads and fully developed fires directly to one side of a carbon-fibre-reinforced sandwich composite. Three different intumescent coatings were applied to sandwich structures and compared to a bench-scale study. The results emphasise intumescent coatings as a promising method to sustain fire resistance, multiplying the time to failure. Nevertheless, the realistic intermediate-scale test using severe direct flame application underlines the extremely short failure times when the actual composite components are tested without any additional insulation. KW - Carbon-fibre-reinforced KW - Fire stability KW - High-temperature properties KW - Mechanical testing KW - Fully developed fire KW - Post-crash scenario PY - 2015 DO - https://doi.org/10.1177/0731684415609791 SN - 0731-6844 SN - 1530-7964 VL - 34 IS - 24 SP - 2029 EP - 2044 PB - Technomic Publ. Co. CY - Westport, Conn. AN - OPUS4-35120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Antje A1 - Langfeld, Kirsten A1 - Ulmer, B. A1 - Andrievici, V. A1 - Hörold, Andreas A1 - Limbach, P. A1 - Bastian, Martin A1 - Schartel, Bernhard T1 - Halogen-free Multicomponent Flame Retardant Thermoplastic Styrene-Ethylene-Butylene-Styrene Elastomers Based on Ammonium Polyphosphate – Expandable Graphite Synergy N2 - Developing flame retarded thermoplastic elastomers (TPES) based on styrene−ethylene−butylene−styrene, polypropylene, and mineral oil is a challenging task because of their very high fire loads and flammability. A promising approach is the synergistic combination of expandable graphite (EG) and ammonium polyphosphate (APP). Cone calorimetry, oxygen index, and UL 94 classification were applied. The optimal EG:APP ratio is 3:1, due to the most effective fire residue morphology. Exchanging APP with melamine-coated APPm yielded crucial improvement in fire properties, whereas replacing EG/APP with melamine polyphosphate did not. Adjuvants, such as aluminum diethyl phosphinate (AlPi), zinc borate, melamine cyanurate, titanium dioxide, dipentaerylthritol, diphenyl-2-ethyl phosphate, boehmite, SiO2, chalk, and talcum, were tested. All flame retardants reinforced the TPE-S. The combination with AlPi is proposed, because with 30 wt % flame retardants a maximum averaged rate of heat emission below 200 kW m−2 and a V-0 rating was achieved. Multicomponent EG/APP/adjuvants systems are proposed as a suitable route to achieve efficient halogen-free flame retarded TPE-S. KW - Thermoplastic elastomers KW - Amonium polyphosphate KW - Expandable graphite KW - Synergy PY - 2017 DO - https://doi.org/10.1021/acs.iecr.7b01177 SN - 0888-5885 VL - 56 IS - 29 SP - 8251 EP - 8263 PB - ACS Publications AN - OPUS4-41509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Watolla, Marie-Bernadette A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Rickard, W.D.A. A1 - Krüger, Simone A1 - Schartel, Bernhard T1 - Intumescent geopolymer-bound coatings for fire protection of steel N2 - The passive fire protection of steel structures and other load-bearing components will continue to gain importance in future years. In the present contribution, novel intumescent aluminosilicate (geopolymer-bound) composites are proposed as fire-protective coatings on steel. Steel plates coated with these materials were exposed to the standard temperature-time curve as defined in ISO 834 – 1:1999. The coatings partially foamed during curing and expanded further during thermal exposure, demonstrating their intumescent characteristic.Thermogravimetryandoscillatory rheometry determined that the intumescent behavior is attributed to a transition to a viscous state (loss factor > 1) in the temperature range of major water release, differing from conventional geopolymers. XRD and SEM images showed that the coatings had characteristics of ceramic or glass-ceramic foams after fire resistance testing, suggesting superior performance under challenging conditions. The thickness of the coatings influenced their foaming and intumescent behavior and thus the time for the coated steel plates to reach 500 °C. A number of additives were also studied with the best performance obtained from samples containing sodium tetraborate.Acoating of just 6mmwas able to delay the time it takes for a steel substrate to reach 500 °C to more than 30 minutes. KW - Geopolymers KW - Fire protection KW - Intumescence KW - Coatings KW - Fire resistance PY - 2017 UR - https://www.ceramic-science.com/articles/all-articles.html?article_id=100558 DO - https://doi.org/10.4416/JCST2017-00035 VL - 8 IS - 3 (Topical issue: Geopolymers) SP - 351 EP - 364 PB - Göller Verlag CY - Baden-Baden AN - OPUS4-42139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deng, C. A1 - Yin, Huajie A1 - Li, R.-M. A1 - Huang, S.-C. A1 - Schartel, Bernhard A1 - Wang, Y.-Z. T1 - Modes of action of a mono-component intumescent flame retardant MAPP in polyethylene-octene elastomer N2 - A mono-component intumescent flame retardant named ethylenediamine-modified ammonium polyphosphate (MAPP) is used in polyethylene-octene elastomer (POE). Insight into the flame-retardant mechanisms of the MAPP is provided from a new perspective. The fire performance of POE/MAPP composites is investigated by oxygen index (OI) and vertical burning (UL-94) tests. POE Composite containing 35 wt% MAPP achieves a V-0 rating, and its OI is 29.3 vol%. The thermogravimetric Analysis (TGA) and Fourier transform infrared spectra (FTIR) confirm that the incorporation of ethylenediamine changes the thermal decomposition of APP, mainly resulting in the formation of char layer with a thermally stable structure. Cone calorimeter analysis revealed the flame-retardant modes of action of MAPP in POE under forced-flaming conditions. Quantitative analysis illustrates that both the residue due to charring and the fuel dilution/flame Inhibition resulting from the release of incombustible products/ phosphorus species decrease the total heat release (fire load) by 20e28%. The residue increases linearly with increasing MAPP content, whereas the reduction in effective heat of combustion levels off. Moreover, the flame-retardant effect resulting from the protective properties of the char is discovered to be the dominant mode of action (up to 85% reduction) with respect to the peak heat release rate, leading to the excellent flame retardancy of POE/MAPP. KW - Ammonium polyphosphate KW - Flame retardant KW - Carbonization KW - Elastomer PY - 2017 DO - https://doi.org/10.1016/j.polymdegradstab.2017.03.006 SN - 0141-3910 SN - 1873-2321 VL - 138 SP - 142 EP - 150 PB - Elsevier AN - OPUS4-39901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Wilkie, Charles A. A1 - Camino, G. T1 - Recommendations on the scientific approach to polymer flame retardancy: Part 2 - concepts N2 - The usage of concepts in scientific communication is critical to our ability to inform the reader about work that has been performed. The significance and thus the quality of scientific discussion rely on the precise use of concepts. In this second part of a two-part paper, concerning the scientific basis of polymer fire retardancy, the proper use of concepts is addressed. Distinct concepts in flame retardancy are discussed, such as fire residue, the correlation of fire performance with char yield according to van Krevelen, catalysis, and wicking. Synergy is discussed in detail, as well as approaches to quantify it, due to its importance for flame retardant polymers. The preceding first paper (part 1) discussed the proper use of scientific terms, thermal analysis, and fire testing. Thus, together these two papers support the community by offering recommendations and addressing some of the most relevant points. They encourage to review scientific practice in the field of flame retardancy of polymers. KW - Char KW - Synergism KW - Flame retardancy KW - Flammability KW - Fire growth indices KW - Synergy index PY - 2017 DO - https://doi.org/10.1177/0734904116675370 SN - 0734-9041 SN - 1530-8049 VL - 35 IS - 1 SP - 3 EP - 20 PB - Sage AN - OPUS4-39084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -