Vol.:(0123456789) 1 3 Experiments in Fluids (2020) 61:30 https://doi.org/10.1007/s00348-019-2864-5 RESEARCH ARTICLE Investigation of fame retarded polypropylene by high‑speed planar laser‑induced fuorescence of OH radicals combined with a thermal decomposition analysis Christopher Geschwindner 1  · Daniela Goedderz 2,3  · Tao Li 1  · Jan Köser 1  · Claudia Fasel 4  · Ralf Riedel 4  · Volker Altstädt 5  · Christian Bethke 5  · Florian Puchtler 6  · Josef Breu 6  · Manfred Döring 3  · Andreas Dreizler 1  · Benjamin Böhm 1 Received: 1 October 2019 / Revised: 6 December 2019 / Accepted: 7 December 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract The combustion of micrometer-sized polypropylene (PP) particles is analyzed in situ using a combination of high-speed planar laser-induced fuorescence of the OH radical (OH-PLIF) and a thermal decomposition analysis. The gas phase is investigated by multiple analytical techniques to gain comprehensive knowledge on the decomposition products of fame retardants and their efect on the combustion process. Neat PP is compared with a formulation consisting of 10 wt% of a phosphorus-containing fame retardant (pentaerythritol spirobis(methylphosphonate), PSMP) which is known to provide gas phase activity. The decomposition of the neat fame retardant, PP and the fame retardant formulation is investigated using a simultaneous analysis (STA) consisting of a thermal gravimetric analysis and a diferential thermal analysis device which is coupled to Fourier-transform infrared spectroscopy and mass spectrometry devices. By this, the release of decomposi- tion products of the fame retardant additive can be determined. The excitation of OH radicals is used to temporally track the difusion fame surrounding the particles during combustion in a laminar fow reactor. The radial distance to the peak reactivity zone of fame retardant containing particles increased by about 70 µm compared with neat PP particles. Tracking the peak OH signal in the difusion fame, during ignition and the early phase of combustion, a decrease in the peak intensity is observed for fame retardant polymer particles. Additionally, cone calorimeter tests are used to evaluate the combustion behavior as a standard test in fame retardancy. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00348-019-2864-5) contains supplementary material, which is available to authorized users. * Christopher Geschwindner geschwindner@rsm.tu-darmstadt.de 1 Reaktive Strömungen und Messtechnik, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany 2 Ernst-Berl Institute for Chemical Engineering and Macromolecular Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 4, 64287 Darmstadt, Germany 3 Fraunhofer Institute for Structural Durability and System Reliability LBF, Schlossgartenstraße 6, 64289 Darmstadt, Germany 4 Institut für Materialwissenschaft, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany 5 Department of Polymer Engineering, University of Bayreuth, Universitätsstraße 30, 95447 Bayreuth, Germany 6 Department of Chemistry, Bavarian Polymer Institute, University of Bayreuth, Universitätstraße 30, 95447 Bayreuth, Germany