Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Technology Basis of the Thermolytic Synthesis of Char Formation Polymeric System
This chapter overviews the sequence of physicochemical transformations during combustion of intumescent compositions and the principle of their fire-retardant action. The results of studying the structure and composition of the products of thermolysis of intumescent components using the Fourier transform infrared spectroscopy, chromatography–mass spectrometry and scanning electron microscopy are summarized. As a result of the studies conducted by the authors, the functions of the main ingredients of intumescent fire-retardant compositions based on MA, PE, APP were revised and refined. Evidence is provided for the fact that pentaerythritol does not manifest itself as a tetrahydric alcohol outside the environment of polar solvents, and therefore, as was assumed in earlier studies, it does not form ether resins with ammonium polyphosphate, which are swollen by gaseous products of melamines thermolysis. Instrumental methods showed that pentaerythritol at temperatures above 190 °C, against the background of crystalline structural rearrangement in the presence of active co-reagents such as melamine, decomposes into formic and acetic aldehydes used in its synthesis. Those, at the indicated temperatures, in the presence of polyphosphoric acid (in the form of an incompletely substituted ammonium phosphate) effectively form a three-dimensional melamine aldehyde structure with melamine. The mechanism of intumescence as a superposition of physicochemical processes determines the necessity and sufficiency of the contributions of each of them to the thermolytic synthesis of the forming char: the formation of a melamine aldehyde polymer, and subsequent gas evolution, expansion and carbonization, has been experimentally proved and theoretically justified. Based on the data on the ability of pentaerythritol to form aldehydes under certain conditions, the authors refine the scientific concept that describes the mechanism of synthesis of pentaphthalic resins. It was shown that along with the reactions of formation of pentaphthalic esters, reactions of phthalic anhydride with aldehydes should be carried out, providing a more branched and crosslinked structure of the resulting resin.
Technology Basis of the Thermolytic Synthesis of Char Formation Polymeric System
This chapter overviews the sequence of physicochemical transformations during combustion of intumescent compositions and the principle of their fire-retardant action. The results of studying the structure and composition of the products of thermolysis of intumescent components using the Fourier transform infrared spectroscopy, chromatography–mass spectrometry and scanning electron microscopy are summarized. As a result of the studies conducted by the authors, the functions of the main ingredients of intumescent fire-retardant compositions based on MA, PE, APP were revised and refined. Evidence is provided for the fact that pentaerythritol does not manifest itself as a tetrahydric alcohol outside the environment of polar solvents, and therefore, as was assumed in earlier studies, it does not form ether resins with ammonium polyphosphate, which are swollen by gaseous products of melamines thermolysis. Instrumental methods showed that pentaerythritol at temperatures above 190 °C, against the background of crystalline structural rearrangement in the presence of active co-reagents such as melamine, decomposes into formic and acetic aldehydes used in its synthesis. Those, at the indicated temperatures, in the presence of polyphosphoric acid (in the form of an incompletely substituted ammonium phosphate) effectively form a three-dimensional melamine aldehyde structure with melamine. The mechanism of intumescence as a superposition of physicochemical processes determines the necessity and sufficiency of the contributions of each of them to the thermolytic synthesis of the forming char: the formation of a melamine aldehyde polymer, and subsequent gas evolution, expansion and carbonization, has been experimentally proved and theoretically justified. Based on the data on the ability of pentaerythritol to form aldehydes under certain conditions, the authors refine the scientific concept that describes the mechanism of synthesis of pentaphthalic resins. It was shown that along with the reactions of formation of pentaphthalic esters, reactions of phthalic anhydride with aldehydes should be carried out, providing a more branched and crosslinked structure of the resulting resin.
Technology Basis of the Thermolytic Synthesis of Char Formation Polymeric System
Springer Series on Polymer and Composite Materials
Zybina, Olga (Autor:in) / Gravit, Marina (Autor:in)
Intumescent Coatings for Fire Protection of Building Structures and Materials ; Kapitel: 2 ; 53-90
05.11.2020
38 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Intumescent coatings , Char , Intumescent char , Intumescent layer , Fire-retardant compositions , Mechanism of char formation , Melamine , Ammonium polyphosphate , Pentaerythritol , Thermal analysis , Infrared spectroscopy , Chromatography–mass spectrometry , Thermolysis , Aminoaldehyde resin Chemistry , Polymer Sciences , Fire Science, Hazard Control, Building Safety , Building Materials , Surfaces and Interfaces, Thin Films , Chemistry and Materials Science
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