TY - CONF A1 - Battig, Alexander T1 - Flame Retardancy Forge on Sustainability - Fun, Food for Thought, Future N2 - This presentation outlines the role biogenic flame retardant fillers play in attaining sustainability goals associated with the bioeconomy. The talk presents biogenic waste compounds as flame retardant syngergists with phosphorus flame retardants in various polymers. T2 - Climate Change @ Fire Science Workshop CY - Berlin, Germany DA - 10.11.2022 KW - Sustainable KW - Flame retardancy KW - Bioeconomy PY - 2022 AN - OPUS4-56285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sanchez Olivares, G. A1 - Battig, Alexander A1 - Goller, Sebastian M. A1 - Rockel, Daniel A1 - Ramirez Gonzáles, V. A1 - Schartel, Bernhard T1 - Imparting Fire Retardancy and Smoke Suppression to Leather during Tanning Processes N2 - Leather is considered a luxury good when used in seating and upholstery. To improve safety, flame retardancy in leather is usually achieved through various finishing processes such as spray or roller coating. These treatments require processing steps that cost time and are laborintensive. One avenue to achieving flame retardancy in leather is to add flame retardants during the tanning process. However, the influence on flame retardancy exerted by specific intumescent additives specifically added during leather tanning has yet to be investigated. This work explores the roles played by intumescent additive compounds in flame retarding leather when they are added during tanning instead of applied as a coating. Via a systematic investigation of various compound mixtures, the flame retardant effects in the condensed and the gas phases are elucidated. The results show a strong impact of melamine in the gas phase and of polyphosphates in the condensed phase. Their impact was quantified in fire and smoke analysis, showing a 14% reduction in the peak of heat release rate, strongly reduced burning lengths, and a 20% reduction in total smoke release compared to nontreated leather. These results illuminate the key role played by specific compounds in the flame retardancy of leather, particularly when they are added specifically during the tanning process instead of being applied as a coating. This method has great potential to reduce processing steps, lower costs, and improve material safety. KW - Leather KW - Fire protection KW - Intumescent additives KW - Smoke suppression PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-564777 SN - 2470-1343 VL - 7 IS - 48 SP - 44156 EP - 44169 PB - ACS AN - OPUS4-56477 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 U6 - 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 - 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 - 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 U6 - 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 - Strommer, Bettina A1 - Battig, Alexander A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Huth, Christian A1 - Böhning, Martin A1 - Schartel, Bernhard T1 - Multifunctional Property Improvements by Combining Graphene and Conventional Fillers in Chlorosulfonated Polyethylene Rubber Composites N2 - The incorporation of nanoparticles like multilayer graphene (MLG) into elastomeric composites boosts their technical performance, such as their mechanical behavior and electrical conductivity. Common filler types (carbon black (CB) and aluminum trihydroxide (ATH)) generally fulfill single, specific purposes and are often used in high loadings. CB typically reinforces rubber mechanically, while ATH increases flame retardancy. Small amounts of MLG reduce these high filler contents and maintain the multifunctional characteristics of rubber composites. In chlorosulfonated polyethylene (CSM) + ATH, an intrinsically flame-retardant rubber was designed to achieve the highest standards such as maximum average of heat emission (MARHE) <90 kW m−2, 3 phrMLG was substituted for 15 phr CB and/or 3 phr ATH via an industrially applicable processing approach. Replacing either CB or ATH resulted in a property profile that was multifunctionally improved in terms of features such as mechanical performance, reduced sorption, and flame retardance. MLG nanocomposites are reported to show promise as an industrially utilizable route to obtain multifunctional high-performance rubbers. KW - Nanocomposites KW - Rubber KW - Multilayer graphene KW - Flame retardancy KW - Synergy KW - Nanoparticles KW - Elastomers PY - 2022 U6 - https://doi.org/10.1021/acsapm.1c01469 SN - 2637-6105 VL - 4 IS - 2 SP - 1021 EP - 1034 PB - ACS Publ. CY - Washington, DC AN - OPUS4-54330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battig, Alexander A1 - Abdou-Rahaman Fadul, Naïssa A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Schartel, Bernhard T1 - Multifunctional Graphene in Flame Retarded Polybutadiene/ Chloroprene/ Carbon Black Composites N2 - Multilayer graphene is investigated as a multifunctional nanofiller to polybutadiene/ chloroprene rubbers (BR/CR) that partially substitutes carbon black (CB) and aluminum trihydroxide (ATH). Loadings of only 3 parts per hundred rubber (phr) MLG replaced 15 phr of CB and/or 3 phr of ATH in BR/CR nanocomposites. Mechanical and fire behavior were investigated, and results point to improved rheological, curing and mechanical properties of MLG-containing rubber composites. T2 - 18th European Meeting on Fire Retardant Polymeric Materials, FRPM21 CY - Budapest, Hungary DA - 29.08.2021 KW - Graphene KW - Rubber KW - Fire Retardant KW - Nanofiller KW - Nanocomposite KW - ATH PY - 2021 AN - OPUS4-53202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battig, Alexander A1 - Sánchez Olivares, Guadalupe A1 - Schartel, Bernhard T1 - Waste not, Want not: Leather Industrial Waste as a Fire Retardant Adjuvant in EVA N2 - An interesting fire retardant behavior of leather wastes collected from local tannery industry was observed in a detailed study on morphological, pyrolysis, forced combustion, flammability, mechanical and rheological properties. T2 - 18th European Meeting on Fire Retardant Polymeric Materials, FRPM21 CY - Budapest, Hungary DA - 29.08.2021 KW - Leather KW - Industrial waste KW - Circular economy KW - Bio-filler KW - Sustainability KW - Ethylene vinyl acetate PY - 2021 AN - OPUS4-53205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Müller, Patrick A1 - Bertin, Annabelle A1 - Schartel, Bernhard T1 - Hyperbranched Rigid Aromatic Phosphorus-Containing Flame Retardants for Epoxy Resins N2 - A rigid aromatic phosphorus-containing hyperbranched flame retardant structure is synthesized from 10-(2,5 dihydroxyphenyl)-10H-9-oxa- 10-phosphaphenanthrene-10-oxide (DOPO-HQ), tris(4-hydroxyphenyl)phosphine oxide (THPPO), and 1,4-terephthaloyl chloride (TPC). The resulting poly-(DOPO-HQ/THPPO-terephthalate) (PDTT) is implemented as a flame retardant into an epoxy resin (EP) at a 10 wt% loading. The effects on EP are compared with those of the monomer DOPO-HQ and triphenylphosphine oxide (OPPh3) as low molar mass flame retardants. The glass transition temperature, thermal decomposition, flammability (reaction to small flame), and burning behavior of the thermosets are investigated using differential scanning calorimetry, thermogravimetric analysis, pyrolysis combustion flow calorimetry, UL 94-burning chamber testing, and cone calorimeter measurements. Although P-contents are low at only 0.6 wt%, the study aims not at attaining V-0, but at presenting a proof of principle: Epoxy resinswith PDTT show promising fire performance, exhibiting a 25% reduction in total heat evolved (THE), a 30% reduction in peak heat release rate (PHRR) due to flame inhibition (21% reduction in effective heat of combustion (EHC)), and an increase in Tg at the same time. This study indicates that rigid aromatic hyperbranched polymeric structures offer a promising route toward multifunctional flame retardancy. KW - Hyperbranched KW - Aromatic KW - Phosphorus KW - Phosphine oxide KW - DOPO KW - Flame retardant KW - Xpoxy resin KW - Rigid PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-525910 SN - 1439-2054 VL - 306 IS - 4 SP - 731 PB - Wiley AN - OPUS4-52591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Battig, Alexander A1 - Sanchez-Olivares, G. A1 - Rockel, Daniel A1 - Maldonado-Santoyo, M. A1 - Schartel, Bernhard T1 - Waste not, want not: The use of leather waste in flame retarded EVA N2 - Leather is among the most ancient, widely used materials worldwide. Industrial-scale leather production produces large quantities of organic waste attained during shaving and buffing steps during processing. In this study, leather wastes (LW) are used as fillers in flame retarded polymer composites. LW is investigated as a multifunctional bio-filler that enhances the fire performance of flame retarded poly(ethylene–vinyl acetate) (EVA) containing phosphorus flame retardants (P-FRs) ammonium polyphosphate (APP) or a melamine-encapsulated APP (eAPP). Using LW from tanneries as adjuvants to enhance P-FRs in EVA reduces industrial wastes that otherwise require costly waste management solutions. Materials are characterized multi-methodically via mechanical tests, electron microscopy, rheology, thermogravimetric analysis, evolved gas analysis, and condensed phase FTIR, also reaction-to-small-flames and cone calorimeter tests. EVA containing 10 wt-% LW and 20 wt-% P-FRs achieve 20% reductions in fire loads versus EVA, and up to 10% reduction in effective heats of combustion versus EVA with equal (30 wt-%) P-FR loadings. Enhanced char stabilization of EVA composites with LW and P-FRs lowered peaks of heat release rates up to 53% compared to EVA, and up to 40% compared to equal P-FRs loadings. Synergisms between LW and P-FRs in EVA are quantified. A chemical decomposition mechanism is proposed. KW - Leather waste KW - Tannery industry KW - EVA KW - Fire protection KW - Flame retardancy KW - Charring PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-532977 SN - 0264-1275 VL - 210 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam AN - OPUS4-53297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battig, Alexander A1 - Markwart, Jens A1 - Wurm, Frederick R. A1 - Schartel, Bernhard T1 - Life is branched — Hyperbranched polyphosphoesters, -di/amidates and –amides in epoxy resins N2 - The demands for modern flame retardants are higher than ever: a flame retardant must function effectively in a certain polymer matrix and avoid critical alterations to the material’s properties. Ideally, a flame retardant additive should be easily miscible and show no sign of leaching or blooming from the matrix. Additionally, the flame retardant should be non-toxic, non-accumulating and biocompatible. Hyperbranched polymers are a promising group of multifunctional flame retardants which fulfill these demands: their complex shape enables high miscibility and avoids leaching or blooming, while their high molecular weight potentially increases biocompatibility and lowers accumulation and toxicity. Moreover, they exhibit a low impact on polymer properties and a good flame retardant performance. This work examines the efficacy and mode of action of phosphorus-based hyperbranched polymeric flame retardants in bisphenol A-based epoxy matrices. To investigate the effect of the complex shape, the hyperbranched polymers are compared to their corresponding monomeric variants. Furthermore, the materials are synthesized to contain systematically varying oxygen-to-nitrogen ratios, allowing for new insight into what role the chemical surrounding of phosphorous plays in flame retardant efficacy. Using a multi-methodical approach, including thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (FTIR), hot stage FTIR, micro combustion calorimetry, differential scanning calorimetry, oxygen index (LOI), UL-94 tests and cone calorimetry experiments, the decomposition mechanisms and the flame retardant modes of action of these flame retardants in epoxy resins are investigated, shedding new light on the chemistry of flame retardancy. T2 - Flame 2018, 29th Annual Conference on Recent Advances in Flame Retardancy of Polymeric Materials CY - Stamford, CT, USA DA - 20.05.2018 KW - Hyperbranched polymers KW - Flame retardancy KW - Fire retardant KW - Pyrolysis PY - 2018 AN - OPUS4-45129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markwart, Jens C. A1 - Battig, Alexander A1 - Zimmermann, Lisa A1 - Wagner, Martin A1 - Fischer, Jochen A1 - Schartel, Bernhard A1 - Wurm, Frederik R. T1 - Systematically controlled decomposition mechanism in phosphorus flame retardants by precise molecular architecture: P−O vs P−N N2 - Flame retardants (FR) are inevitable additives to many plastics. Halogenated organics are effective FRs but are controversially discussed due to the release of toxic gases during a fire or their persistence if landfilled. Phosphorus-containing compounds are effective alternatives to halogenated FRs and have potential lower toxicity and degradability. In addition, nitrogencontaining additives were reported to induce synergistic effects with phosphorus-based FRs. However, no systematic study of the gradual variation on a single phosphorus FR containing both P−O and P−N moieties and their comparison to the respective blends of phosphates and phosphoramides was reported. This study developed general design principles for P−O- and P−N-based FRs and will help to design effective FRs for various polymers. We synthesized a library of phosphorus FRs that only differ in their P-binding pattern from each other and studied their decomposition mechanism in epoxy resins. Systematic control over the decomposition pathways of phosphate (PO(OR)3), phosphoramidate (PO(OR)2(NHR)), phosphorodiamidate (PO(OR)(NHR)2), phosphoramide (PO(NHR)3), and their blends was identified, for example, by reducing cis-elimination and the formation of P−N-rich char with increasing nitrogen content in the P-binding sphere. Our FR epoxy resins can compete with commercial FRs in most cases, but we proved that the blending of esters and amides outperformed the single molecule amidates/diamidates due to distinctively different decomposition mechanisms acting synergistically when blended. KW - Phosphorus KW - Flame retardants KW - Epoxies KW - Mechanistic study KW - Toxicity PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-481549 SN - 2637-6105 VL - 1 IS - 5 SP - 1118 EP - 1128 PB - ACS AN - OPUS4-48154 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 - CONF A1 - Battig, Alexander A1 - Markwart, J.C. A1 - Wurm, F.R. A1 - Schartel, Bernhard T1 - Hyperbranched Polymeric Flame Retardants N2 - Most synthetic polymers have a high fire load, and as a result, they require flame retardants (FRs) to ensure their safe use. Phosphorus plays an important role in flame retardancy and has the potential to replace halogenated variants, which are assumed to be harmful to the environment and health. Among phosphorus-based FRs, there exists a trend towards polymeric, high molar mass molecules with complex molecular architectures. In this project, we synthesized a novel series of so-called phosphorus-based hyperbranched polymeric FRs and investigated their use as multifunctional additives to high-performance polymers, i.e. epoxy resins. By cleverly designing the chemical structure to contain varying amounts of P-O and P-N bonds, new insight into the chemical mechanism of flame retardancy was gained, and by comparing the hyperbranched polymers to their monomeric counterparts, a greater understanding of the role of complex architecture was won. This talk aims at presenting some of these results and proposes chemical mechanisms that illustrate what role these novel hyperbranched flame retardants play in molecular firefighting. T2 - AMI Fire Resistance in Plastics 2019 CY - Cologne, Germany DA - 03.12.2019 KW - Epoxy resin KW - Flame retardant KW - Hyperbranched polymers KW - Phosphoester KW - Phosphoramidate KW - Phosphoramide KW - Phosphorodiamidate KW - Pyrolysis PY - 2019 AN - OPUS4-50034 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 - 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 - 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 - Battig, Alexander A1 - Abdou-Rahaman Fadul, Naïssa A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Schartel, Bernhard T1 - Multifunctional graphene nanofiller in flame retarded polybutadiene/chloroprene/carbon black composites N2 - To curtail flammability risks and improve material properties, flame retardants (FRs) and fillers are mixed into rubbers. High loadings of aluminum trihydroxide (ATH) and carbon black (CB) are the most used FRs and reinforcing additive, respectively, in rubbers. To reduce loading without losing mechanical properties, partial substitution of ATH as well as CB by low amounts of multilayer graphene (MLG) nanoparticles is investigated. The high aspect ratio MLG is made of ten graphene sheets. In polybutadiene/chloroprene (BR/CR) nanocomposites 3 phr MLG replaced 15 phr CB and/or 3 phr ATH. Material and mechanical properties as well as fire behavior of the nanocomposites are compared to BR/CR with 20 phr CB both with and without 50 phr ATH. MLG appears as a promising nanofiller to improve the functional properties: replacement of CB improved rheological, curing, and mechanical properties; substitution of ATH improved nanocomposite properties without affecting flame retardancy. KW - Nanocomposites KW - Rubber KW - Multilayer graphene KW - Carbon black KW - Polybutadiene/chloroprene KW - Graphene PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-523468 SN - 1618-7229 VL - 21 IS - 1 SP - 244 EP - 262 PB - De Gruyter AN - OPUS4-52346 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 - CONF A1 - Battig, Alexander A1 - Markwart, J. A1 - Wurm, F.R. A1 - Schartel, Bernhard T1 - Hyperbranched Polymeric Flame Retardants: The Role of Chemical Composition and Complex Shape N2 - The need to develop effective flame retardants that retain polymer properties and are safe for consumers and the environment is a continuous challenge for material scientists. While halogenated flame retardants were once commonplace, the shift to non-halogenated materials has steadily progressed due to concerns over impact on health and the environment. One prominent group of flame retardants has become a viable alternative for halogenated materials, namely phosphorus-based flame retardants. The chemical versatility of phosphorus-based flame retardants and the ability to work as reactive or additive compounds makes them ideally suited for modern materials. There exists a trend toward complex, polymeric, and multifunction flame retardants, as these materials show greater flame retardancy performance than low molecular weight counterparts and affect material properties to a much lesser extent. One group of organophosphorus flame retardants that shows great potential for high-performance polymers like epoxy resins are hyperbranched phosphorus-based polymers. These additives exhibit great miscibility with the polymer matrix and a significantly decreased diffusion through the material, which greatly reduce leaching or blooming out of the matrix. Moreover, the material’s thermal stability remains intact at elevated temperatures due to its low impact on the glass transition temperature. Finally, following market trends and legislation such as the guidelines for the Restriction of Hazardous Substances Directive implemented by REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) in the EU, these macromolecules are non-accumulating, non-toxic and have a lower risk of leeching or blooming from the matrix, further reducing environmental impact. The work presented herein focusses on two distinct parts studying hyperbranched polymeric flame retardants and their corresponding monomeric compounds. The first part, involving the low molecular weight components, investigated the role of the chemical surrounding of phosphorus in terms of flame retardant efficacy. Here, a systematic variance of the surrounding of phosphorus was investigated: by changing the ratio of oxygen to nitrogen (4:0 until 1:3), four materials, namely phosphoester (4:0), phosphoramidate (3:1), phosphorodiamidate (2:2), and phosphoramide (1:3), were synthesized, characterized, and finally added to Bisphenol A based epoxy resins (10 wt.-% loading). Pyrolysis investigations showed that low molecular weight components volatize at lower temperatures than the polymer matrix. Additionally, cone calorimeter measurements and TGA-FTIR investigations show trends in respect to FR efficacy in pyrolysis and full flaming conditions. The second part involves the hyperbranched variants of the monomeric counterparts and investigates the role of complex shape on flame retardant efficacy. By comparing the low to the high molecular weight compounds, the influence of the complex shape becomes apparent and can be quantified. Cone calorimeter measurements show an increase in flame retardancy for some materials, while for others, the mode of action is altered. By implementing a multi-methodical approach, various flame retardancy aspects, from pyrolysis behavior in the gas and condensed phase, to ignitability / reaction-to-small-flame performance, to action in forced flammability experiments, are identified and quantified, allowing for a clearer understanding of the behavior in fire of these novel flame retardants. By comprehending the roles of chemical composition and complex shape, it opens the path for new and effective multifunctional, polymeric flame retardants with decreased PBT, higher miscibility, and low impact on Tg. This work is funded by the Deutsche Forschungsgemeinschaft (DFG: SCHA 730/15-1; WU 750/8-1). T2 - 10th International Conference on Modification, Degradation and Stabilization of Polymers, MoDeSt2018 CY - Tokyo, Japan DA - 02.09.2018 KW - Hyperbranched polymer KW - Flame retardant KW - Phosphoester KW - Phosphoramidate KW - Phosphorodiamidate KW - Pphosphoramide PY - 2018 AN - OPUS4-45965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battig, Alexander A1 - Markwart, J. C. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Hyperbranched Flame Retardants N2 - Benefits of hyperbranched structure: Molecular weight, miscibility, number of FR groups, end-group functionalization, glass transition temperature, decreased PBT. Examples of hyperbranched FRs: Charring agent, silicone, triazine, etc. Systematic study of effect of chemical surrounding and impact of Complex shape of phosphorus-based hyperbranched polymers on flame retardant efficacy in epoxy resins. T2 - 16th Annual Conference on Trends in Fire Safety and Innovative Flame Retardants for Plastics CY - Würzburg, Germany DA - 23.10.2018 KW - Flame retardant KW - Hyperbranched polymers KW - Phosphoester KW - Phosphoramidate KW - Phosphorodiamidate KW - Phosphoramide KW - Pyrolysis PY - 2018 AN - OPUS4-46371 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battig, Alexander A1 - Markwart, J. A1 - Velencoso, M. M. A1 - Wurm, F. R. A1 - Schartel, Bernhard T1 - Hyperbranched Polyphosphoesters, -di/amidates and –amides as Novel Flame Retardants for Epoxy Resins: Understanding the Role of Chemical Composition N2 - The use of phosphorus-containing flame retardants as a viable alternative to their widely used halogen-containing counterparts has been the source of much recent research. As the search for an effective flame retardant for specific polymeric systems continues, a new class of flame retardants have shown promising results, namely hyperbranched polyphosphoesters and their derivatives. These macromolecules promise to combine the effects of complex, hyperbranched structures with the flame retarding effects of phosphorus, enabling a high miscibility and processability, as well as a lower impact on glass transition temperature and decreased diffusion from the polymer matrix. These and other functions enable them to act as multifunctional additives. In recent times, phosphorus-based hyperbranched materials and their efficacy as flame retardants have been described in literature. Often, the inclusion of nitrogen atoms into the chemical surrounding of phosphorus has lead to reports of increased flame retarding performance through synergistic effects. However, a comprehensive study of the relationship between nitrogen and phosphorus in hyperbranched polymers is lacking. The aim of this work is to determine the efficacy of novel, phosphorus-based hyperbranched polymers compared to other, commercially available, previously studied flame retardants and to investigate the molecular flame retarding mechanism of these complex structured macromolecules. Among one of the key aspects here is the modification of the O:N ratio of the phosphorus-containing repeating units of these hyperbranched polymers. The newly described synthesis route yields trifunctional monomers of the desired composition, which undergo an A2+B3-type polymerization via radical thiol-ene reactions, producing polyphosphoesters, -amidates, -diamidates, or -amides, respectively. By precisely tailoring the nitrogen and oxygen ratio in the chemical surrounding of phosphorus, a more comprehensive picture of the structure-property relationship of these materials may be gained. Furthermore, by adjusting the aromaticity of the hydrocarbon moieties in these trifunctional monomers, an optimization of flame retarding properties, such as increased charring, is aimed to be achieved. Additionally, the trifunctional monomers themselves act as low molecular weight fire retardants; therefore, by comparing the performance of these monomers to their high molecular weight, hyperbranched, polymeric counterparts, an understanding of the role of molecular architecture in designing a more effective flame retardant can be gained. Finally, several epoxy resin matrices, common in high-tech industrial applications, are investigated in the interest of comprehending the interaction between these novel hyperbranched flame retardant additives and their surrounding polymeric matrix. In order to determine the flame retardancy mechanism of these materials, a multi-methodological approach is selected, thus offering a high volume of correlating data. Using Fourier-transform infrared spectroscopy (FTIR) coupled with thermogravimetric analysis (TGA), as well as pyrolysis combustion flow calorimetry (PCFC), provides evidence of mass loss processes, their respective decomposition products, and the heat released by volatiles in the gas phase during pyrolysis, while hot-stage FTIR offers information of the decomposition products occurring in the condensed phase. Limiting oxygen index (LOI) and UL-94 help to quantify and categorize the materials’ flammability, while the use of a cone calorimeter offers valuable insight into the fire behavior in forced flaming conditions, providing heat release rates, smoke and CO/CO2 production, amount of residue, and other important indices. Finally, the use of differential scanning calorimetry (DSC) provides information of material properties such as glass transition temperatures, and the implementation of blooming tests serves to examine the reduction of molecular mobility in the matrix. By varying the architecture of the flame retardants – in the O:N ratio of the chemical surrounding of phosphorus and in the aromatic composition of the monomers’ hydrocarbon moieties – and by comparing low versus high molecular weight species in varied epoxy resin matrices, as well as through the use of a multi-methodological approach, new insight into the use and the mode of action of these components as flame retardants for modern materials can be won. T2 - FRPM 2017, 16th European Meeting on Fire Retardant Polymeric Materials CY - Manchester, UK DA - 03.07.2017 KW - Hyperbranched polymer KW - Phosphoester KW - Phosphor(di)amidate KW - Phosphoramide KW - Flame retardant KW - Epoxy resin PY - 2017 AN - OPUS4-40948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strommer, Bettina A1 - Battig, Alexander A1 - Schulze, Dietmar A1 - Agudo Jacome, Leonardo A1 - Schartel, Bernhard A1 - Böhning, Martin T1 - Shape, orientation, interaction, or dispersion: valorization of the influence factors in natural rubber nanocomposites N2 - The addition of nanoparticles as reinforcing fillers in elastomers yields nanocomposites with unique property profiles, which opens the door for various new application fields. Major factors influencing the performance of nanocomposites are studied by varying the type and shape of nanoparticles and their dispersion in the natural rubber matrix. The industrial applicability of these nanocomposites is put into focus using two types of graphene and a nanoscale carbon black, all commercially available, and scalable processing techniques in the form of a highly filled masterbatch production via latex premixing by simple stirring or ultrasonically assisted dispersing with surfactant followed by conventional two-roll milling and hot pressing. Different processing and measurement methods reveal the potential for possible improvements: rheology, curing behavior, static and dynamic mechanical properties, swelling, and fire behavior. The aspect ratio of the nanoparticles and their interaction with the surrounding matrix prove to be crucial for the development of superior nanocomposites. An enhanced dispersing method enables the utilization of the improvement potential at low filler loadings (3 parts per hundred of rubber [phr]) and yields multifunctional rubber nanocomposites: two-dimensional layered particles (graphene) result in anisotropic material behavior with strong reinforcement in the in-plane direction (157% increase in the Young's modulus). The peak heat release rate in the cone calorimeter is reduced by 55% by incorporating 3 phr of few-layer graphene via an optimized dispersing process. KW - Graphene KW - Natural rubber KW - Nanocomposites KW - Anisotropy KW - Fire behavior PY - 2023 U6 - https://doi.org/10.5254/rct.23.77961 SN - 0035-9475 SN - 1943-4804 VL - 96 IS - 1 SP - 40 EP - 58 PB - Allen Press CY - Lawrence (KA), USA AN - OPUS4-57568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -