TY - JOUR A1 - Hartwig, A. A1 - Pütz, D. A1 - Schartel, Bernhard A1 - Bartholmai, Matthias A1 - Wendschuh-Josties, M. T1 - Combustion behaviour of epoxide based nanocomposites with ammonium and phosponium bentonites N2 - The influence of different organobentonites on the decomposition and the combustion behaviour of an epoxy resin were examined. The epoxy resin is a cationically polymerised cycloaliphatic epoxy resin flexibilised with poly(tetrahydrofuran) (PTHF), with hydroxyl endgroups. The bentonite was modified with either an ammonium or a phosphonium salt. The thermal decomposition of the PTHF induced by the initiator, used for the cationic polymerisation, did neither take place for the nanocomposite based on the ammonium bentonite nor for that based on the phosphonium bentonite. This improved decomposition characteristic lead to a larger time to ignition for both kinds of nanocomposites compared to the not modified polymer, which is not the case for other polymer/clay nanocomposites described in the literature. The fire behaviour was investigated using limiting oxygen index (LOI), a horizontal burner test and a cone calorimeter. The forced flaming conditions in the cone calorimeter were varied using different external heat fluxes between 30 and 70 kW · m-2. The fire behaviour of the nanocomposites was improved in comparison to the polymer, and phosphonium bentonite was superior to ammonium bentonite. The main mechanism is a barrier formation resulting in a reduction of the fire growth rate, which was more pronounced in the case of high external heat fluxes. KW - Cationic polymerisation KW - Clay KW - Combustion KW - Degradation KW - Epoxide KW - Nanocomposite PY - 2003 U6 - https://doi.org/10.1002/macp.200300047 SN - 1022-1352 SN - 1521-3935 VL - 204 IS - 18 SP - 2247 EP - 2257 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartholmai, Matthias A1 - Schartel, Bernhard T1 - Layered silicate polymer nanocomposites: new approach or illusion for fire retardancy? Investigations of the potentials and the tasks using a model system N2 - Polymeric nanocomposites are discussed as one of the most promising advanced materials whose nanoscale effects can be exploited for industry. Layered silicate polypropylene-graft-maleic anhydride nanocomposites are investigated as a model to clarify the potential of such materials in terms of fire retardancy. The nanostructure is characterized using transmission electron microscopy (TEM) and shear viscosity. The fire behavior is characterized using different external heat fluxes in cone calorimeter, limiting oxygen index and UL 94 classification. A comprehensive fire behavior characterization is presented which enables an assessment of the materials’ potential with respect to different fire scenarios and fire tests. The influence of morphology and the active mechanisms are discussed, such as barrier formation and changed melt viscosity. To our knowledge, it is the first attempt to illuminate the concept’s strengths, such as the reduction of flame spread, and weaknesses, such as the lack of influence on ignitability, in a clear, comprehensive and detailed manner. KW - Fire retardancy KW - Nanocomposites KW - Cone Calorimeter KW - LOI KW - UL94 KW - Flame retardance KW - poly(propylene) (PP) KW - Organoclay PY - 2004 UR - http://www3.interscience.wiley.com/cgi-bin/jissue/109085890 SN - 1042-7147 SN - 1099-1581 VL - 15 IS - 7 SP - 355 EP - 364 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-3706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Kunze, Ralf A1 - Bartholmai, Matthias A1 - Neubert, Dietmar A1 - Schriever, Robert T1 - TG-MS and TG-FTIR applied for an unambiguous thermal analysis of intumescent coatings N2 - Thermogravimetry (TG), thermogravimetry coupled with mass spectroscopy (TG-MS) and thermogravimetry coupled with Fourier transform infrared spectroscopy (TG-FTIR) were used to characterise the thermo-oxidative behaviour of two intumescent coating materials. The temperature dependence, the corresponding volatile products and the amount of residue of the different processes were determined. Using both TG-MS and TG-FTIR results in an unambiguous interpretation of the volatile products. Characteristics such as the influence of endothermic reactions, the release of non-flammable gases, the dehydrogenation enhancing the char formation and the stability of the cellular char were discussed in detail. It was demonstrated, that TG, TG-MS and TG-FTIR are powerful methods to investigate mechanisms in intumescent coatings and that they are suitable methods in respect to quality assurance and unambiguous identification of such materials. KW - Intumescent coating materials KW - TG KW - TG-FTIR KW - TG-MS PY - 2002 U6 - https://doi.org/10.1023/A:1022272707412 SN - 1388-6150 SN - 1418-2874 SN - 0368-4466 SN - 1572-8943 VL - 70 IS - 3 SP - 897 EP - 909 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-2133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartholmai, Matthias A1 - Schriever, Robert A1 - Schartel, Bernhard T1 - Influence of external heat flux and coating thickness on the thermal insulation properties of two different intumescent coatings using cone calorimeter and numerical analysis N2 - Polymeric intumescent coatings are fire protective materials that increase their thermal resistance when exposed to high temperatures to prevent building structures from damage. The idea of the investigation was to develop a simple test method to determine the time dependent thermal conductivity of intumescent coatings. Therefore steel plates were coated with two different intumescent systems. During cone calorimeter tests the temperature at the back side of the coated plates was measured. These results were used to calculate the time dependent thermal resistance of the protective layer with the simulation program IOPT2D for different external heat fluxes and different layer thickness. KW - Intumescent coatings KW - Thermal resistance KW - Cone calorimetry KW - Numerical analysis PY - 2003 U6 - https://doi.org/10.1002/fam.823 SN - 0308-0501 SN - 1099-1018 VL - 27 IS - 4 SP - 151 EP - 162 PB - Heyden CY - London AN - OPUS4-2633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Bartholmai, Matthias A1 - Knoll, Uta T1 - Some comments on the use of cone calorimeter data N2 - The cone calorimeter has become one of the most important and widely used instruments for the research and development of fire retarded polymeric materials. The paper addresses three important ways in which the principal setup influences the results — factors which sometimes do not receive due consideration when drawing conclusions. The paper discusses in detail the impact on cone calorimeter results of the choice of external heat flux, the influence on the peak of heat release rate of sample thickness and thermal feedback from the back of the sample, and the influence on irradiance of the horizontal and vertical distances from the cone heater. KW - Cone Calorimeter KW - Fire retardancy KW - Fire testing KW - Nanocomposites KW - Intumescence PY - 2005 U6 - https://doi.org/10.1016/j.polymdegradstab.2004.12.016 SN - 0141-3910 SN - 1873-2321 VL - 88 IS - 3 SP - 540 EP - 547 PB - Applied Science Publ. CY - London AN - OPUS4-7211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Bartholmai, Matthias A1 - Knoll, Uta T1 - Some comments on the main fire retardancy mechanisms in polymer nanocomposites N2 - Barrier formation and increasing the melt viscosity are addressed as the two main general fire retardancy mechanisms of polymer nanocomposites. They result in specific impacts on fire properties that consequentially cause varying flame retardancy efficiency in different fire tests. The barrier formation retards mainly flame spread (peak of heat release rate) in developing fires, but does not reduce fire load (total heat evolved), ignitability or flammability (limiting oxygen index, UL 94). Furthermore, this flame retardancy effect increases with increasing irradiation and vanishes with decreasing irradiation. The increased melt viscosity prevents dripping, which is beneficial or disadvantageous depending on the fire test used. In some test, it become the dominant influence, transforming self-extinguishing samples into flammable materials or causing wicking. Advantages and the limits are sketched comprehensively for exploiting the main general fire retardancy mechanisms of polymer nanocomposites. It is concluded that barrier formation and changing the melt viscosity in nanocomposites are not sufficient for most applications, but must be accompanied by additional mechanisms in special systems or in combination with other flame retardants. KW - Flame retardance KW - Nanocomposites KW - Organoclay KW - Cone calorimeter KW - Flammability PY - 2006 U6 - https://doi.org/10.1002/pat.792 SN - 1042-7147 SN - 1099-1581 VL - 17 IS - 9-10 SP - 772 EP - 777 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-13868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Liers, A. A1 - Schiller, J. T1 - Radio-based multi-sensor system for person tracking and indoor positioning N2 - Sensor based person tracking is a challenging topic. The main objective is positioning in areas without GPS connection, i.e. indoors. A research project is carried out at BAM, Federal Institute for Materials Research and Testing, to develop and to validate a multi-sensor system for 3D localization. It combines body motion sensing and a guard system for the tracking and recording of the status of persons. The so named BodyGuard system was designed for sensor-based monitoring and radio-based transmission of the movement of a person. Algorithms were developed to transform the sensor data into a spatial coordinate. This paper describes how the BodyGuard system operates, which main components were used in the system, how the individual sensor data are converted into 3D motion data, with which algorithms the individual sensors are processed, how individual errors are compensated and how the sensor data are merged into a 3D Model. Final objective of the BodyGuard system is to determine the exact location of a person in a building, e.g. during fire-fighting operations. T2 - WPNC '12 - 9th Workshop on positioning, navigation and communication 2012 CY - Dresden, Germany DA - 2012-03-15 KW - Wireless sensor network (WSN) KW - Embedded systems KW - Sensor calibration and validation KW - Person tracking KW - Inertial navigation system KW - Inertial measurement unit PY - 2012 IS - PS 11 SP - 1 EP - 7 CY - Dresden AN - OPUS4-26028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Bennetts, V.H. A1 - Lilienthal, A.J. A1 - Bartholmai, Matthias A1 - Schiller, J.H. T1 - Gas source localization with a micro-drone using bio-inspired and particle filter-based algorithms N2 - Gas source localization (GSL) with mobile robots is a challenging task due to the unpredictable nature of gas dispersion, the limitations of the currents sensing technologies, and the mobility constraints of ground-based robots. This work proposes an integral solution for the GSL task, including source declaration. We present a novel pseudo-gradient-based plume tracking algorithm and a particle filter-based source declaration approach, and apply it on a gas-sensitive micro-drone. We compare the performance of the proposed system in simulations and real-world experiments against two commonly used tracking algorithms adapted for aerial exploration missions. KW - Autonomous micro UAV KW - Chemical and wind sensing KW - Gas source localization KW - Particle filter PY - 2013 U6 - https://doi.org/10.1080/01691864.2013.779052 SN - 0169-1864 SP - 725 EP - 738 PB - VNU Sciences Pr. CY - Utrecht AN - OPUS4-28010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartholmai, Matthias A1 - Neumann, Patrick P. T1 - Adaptive ortsaufgelöste Gaskonzentrationsmessung mit einer Mikrodrohne KW - Gasmessung KW - Gasemission KW - Emissionskontrolle KW - Windvektor KW - Mikrodrohne KW - Data-Mapping KW - Gas measurement KW - Gas emission KW - Emission control KW - Wind vector KW - Micro-drone KW - Data mapping PY - 2011 U6 - https://doi.org/10.1524/teme.2011.0158 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 78 IS - 10 SP - 470 EP - 478 PB - Oldenbourg CY - München AN - OPUS4-24652 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Prager, Jens T1 - Device concept for the generation of guided waves for early damage detection N2 - In this study a method for early damage detection is investigated based on the directed excitation and measuring of Lamb waves (guided waves). The objective is to make a statement about the practicability of a Lamb wave generator (LWG) and about the application relevant parameters (specimen materials and dimensions, wave characteristics, excitation, transmission und reflection). Guided waves enable an effective differentiation of structural and defective indications as well as a classification of different defect types. For the investigations, a LWG was developed which combines the advantages of the single excitation of a piezoelectric actuator and the possibility of a group excitation. Algorithms were developed to identify and analyze damage patterns (cracks, wholes, weakening). T2 - Eurosensors XXVI CY - Kraków, Poland DA - 2012-09-09 KW - Lamb wave KW - Guided wave KW - DDS KW - SHM KW - Early damage detection PY - 2012 U6 - https://doi.org/10.1016/j.proeng.2012.09.363 SN - 1877-7058 VL - 47 SP - 1185 EP - 1188 PB - Elsevier AN - OPUS4-27552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -