Synthese von P-/Si-(Bio-)Polyolen und maßgeschneiderten katalytischen Nanofüllstoffen: Verbesserung des Flammschutzes und Rauch/Toxizitätsminderung von flexiblen PU-Schäumen
Kunststofftechnik
Zusammenfassung der Projektergebnisse
The project has addressed the future of flame retardant flexible polyurethane foams (FPUF), and thus one of the most important and demanding challenges in flame retardancy of polymeric materials. Unmodified FPUF is easily ignitable and highly flammable due to the combustibility of PU combined with the thermal insulation of the foam structure and its large surface area. The high thermal inertia resulted in rapid heating of the top layer reducing time to ignition and speeding up flame spread. In case of fire, PU release not only a large amount of heat but also toxic gases such as CO, HCN, and NOx, which can easily cause human death by suffocation. Therefore, it is essential to endow FPUF with efficient flame retardancy and smoke suppression. Innovative multicomponent synergistic combinations are demanded to realize a halogen-free flame retardancy fulfilling the high demands for applications within railway vehicles or aviation. What is more, the current change towards using renewable sources was addressed: soybeanoil based and castor-oil based polyols were used, phosphorylated polyols and phosphorylated soybean-oil based polyol was applied to realize intrinsically flame retardant FPUFs. Different phosphorus flame retardants / flame retardant combinations were investigated, and the combination of phosphorus flame retardant with EG was identified as a general promising synergistic solution. Flame inhibition in the gas phase and the formation of a protective layer in the condensed phase works synergistically together, what is more, distinct phosphorus flame retardants together with EG show a synergistic mechanism in the condensed phase. The usually fluffy expanded graphite worms are agglutinated, the fire residue is stabilized. In the right mixture of phosphorus flame retardant and EG, the thermal insulation of the fire residue becomes sufficient to yield an early extinguishing. The incomplete pyrolysis results in a crucially reduced mass loss, fire load, smoke production, and production of toxic gases. The flame retardancy and smoke suppression effect via incomplete pyrolysis outperforms all the tested approaches to tackle the smoke production by catalytical sites / nanoparticle. Considerable efforts were spent in the production of comparable foams. Density and foam structure were controlled to ensure similarity; the mechanical properties were checked. Comprehensive investigation of the pyrolysis, flammability, and fire behaviour was applied to understand the burning and fire phenomena of the foams and their flame retardancy. We identify and quantify the different flame retardant modes of action, and we propose the mechanism behind flame retardancy and synergy. This work produces scientific understanding of the flame retardancy of FPUF, and sketches promising routes and can be used as fundament for evidenced based future development. Apart from the scientific content, this project was performed in co-operation with a leading scientific working group at USTC in China. The BAM employee learned a lot in a five-month guest stay at USTC, working in the synthesis laboratories and preparing FPUFs. We learned a lot about working together with Chinese scientist, especially when the original planned working program did not function well and unforeseen circumstances, such as the COVID-19 pandemic, cut down so much of the planed exchange. Although in part quite far away from the initially planed flame retardant FPUF systems and crucially delayed, we addressed all the topics and approaches with alternative approaches. Several of these alternative works resulted in important and joint publications.
Projektbezogene Publikationen (Auswahl)
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Effects of novel phosphorus-nitrogen-containing DOPO derivative salts on mechanical properties, thermal stability and flame retardancy of flexible polyurethane foam. Polymer Degradation and Stability, 177, 109160.
Ma, Shicong; Xiao, Yuling; Zhou, Feng; Schartel, Bernhard; Chan, Yin Yam; Korobeinichev, Oleg P.; Trubachev, Stanislav A.; Hu, Weizhao; Ma, Chao & Hu, Yuan
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A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam. Polymers for Advanced Technologies, 33(1), 326-339.
Chan, Yin Yam; Ma, Chao; Zhou, Feng; Hu, Yuan & Schartel, Bernhard
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Flame retardant flexible polyurethane foams based on phosphorous soybean-oil polyol and expandable graphite. Polymer Degradation and Stability, 191, 109656.
Chan, Yin Yam; Ma, Chao; Zhou, Feng; Hu, Yuan & Schartel, Bernhard
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Flame Retardant Flexible Polyurethane Foams Using Phosphorous Soybean-oil-based Polyol and Expandable Graphite. 18th European Meeting on Fire Retardant Polymeric Materials, FRPM21, Budapest, Hungary, 29th August - 1st September 2021
Y. Y. Chan, C. Ma, F. Zhou, Y. Hu & B. Schartel
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Synthesis of Ethyl (Diethoxymethyl)phosphinate Derivatives and Their Flame Retardancy in Flexible Polyurethane Foam: Structure-flame Retardancy Relationships. Polymer Degradation and Stability, 188, 109557.
Zhou, Feng; Ma, Chao; Zhang, Kang; Chan, Yin yam; Xiao, Yuling; Schartel, Bernhard; Doring, Manfred; Wang, Bibo; Hu, Weizhao & Hu, Yuan
