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 JF - Macromolecular materials and engineering 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 - Schartel, Bernhard A1 - Wilkie, Charles A. A1 - Camino, Giovanni T1 - Recommendations on the scientific approach to polymer flame retardancy: Part 1—Scientific terms and methods JF - Journal of Fire Sciences N2 - The correct use of scientific terms, performing experiments accurately, and discussing data using unequivocal scientific concepts constitute the basis for good scientific practice. The significance and thus the quality of scientific communication rely on the proper use of terms and methods. It is the aim of this two-part article to support the community with recommendations for discussing the flame retardancy of polymers by addressing some of the most relevant points. The first article (part one of two) clarifies some scientific terms and, in some cases, such as for ‘‘pyrolysis,’’ ‘‘thermal decomposition,’’ and ‘‘fire resistance,’’ critically discusses their definitions in the field of fire science. Several comments are made on proper fire testing and thermal analysis, including some thoughts on uncertainty in fire testing. The proper use of distinct concepts in flame retardancy is discussed briefly in the subsequent second article (part two). This article tries to Balance imparting background on the subject with recommendations. It encourages to check scientific practice with respect to communication and applying methods. KW - Pyrolysis KW - Fire testing KW - Char KW - Flame retardant KW - Flammability KW - Fire property PY - 2016 DO - https://doi.org/10.1177/0734904116675881 SN - 0734-9041 SN - 1530-8049 VL - 34 IS - 6 SP - 447 EP - 467 PB - SAGE AN - OPUS4-38115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schartel, Bernhard A1 - Dittrich, Bettina A1 - Hofmann, D. A1 - Wartig, K.-A. A1 - Mülhaupt, R. T1 - Born in fire to kill fire – graphene in flame retardant nanocomposites N2 - Carbon black, multiwall carbon nanotubes, expanded graphite, multilayer graphene and graphene are compared comprehensively as flame retardants in nanocomposites to each other. Different polymer matrices are investigated as well as changing the concentration of the carbon fillers. Distinct combinations of graphene with conventional flame retardants are investigated. Phenomena and mechanisms are identified controlling the pyrolysis and fire behavior. The viscosity of the nanocomposites and their thermal conductivity as well are dramatically changed compared to the polymers influencing the time to ignition and flammability. During pyrolysis graphene functioned as inert filler and formed a residual protective layer reducing the peak heat release rate. The influence of graphene on the effectivity of various conventional halogen-free flame retardants depends strongly on their modes of action. The addition of a small amount of graphene to an intumescent flame retardant poly(propylene) led to an improvement in the cone calorimeter. The further increase of graphene content gained deceleration of swelling and a decrease of the final height of the intumescent layer. In combination with metal hydroxide, 1 wt% graphene closed the macroscopic surface structure and densified the microscopic structure of the fire residues tremendously. Due to this improved residue structure, metal hydroxides and graphene showed synergistic cooperation in terms of oxygen index and UL 94 classification (HB/V-1 to V-0). T2 - Rudolstädter Kunststoff-Tag CY - Rudolstadt, Germany DA - 12.10.2016 KW - Graphene KW - Nanocomposite KW - Flame retardant KW - Flammability KW - Pyrolysis PY - 2016 AN - OPUS4-38116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -