Studies of Flame Retardant Mechanisms Associated with Carbon-Michael Rigid Foams: A Non-Isocyanate Replacement for Polyurethane Foams

摘要

Carbon-Michael(C-M) addition chemistry is a variation of the Michael reaction to form a carbon-carbon bond. An example C-M polymerization reaction is the base-catalyzed multifunctional acetoacetate reaction to a multifunctional acrylate to generate crosslinked polyester. The reaction is a possible non-isocyanate replacement system for Polyurethane (PU) foams. C-M prepared foams are very similar to PU foams in many ways in terms of mechanical, thermal transport, and other physical properties. Thus, C-M foams can be used in sealant and insulation applications like the current PU foams. However, C-M foams lack the fire retardant properties that PU foams inherently possess. For commercial applications, polymer foam systems must meet certain low flammability requirements and thus require flame retardants (FR) to meet these requirements. Studies were completed to identify suitable flame retardants for C-M foam applications. Two potential separate FR systems were identified as potential candidates to lower the flammability of C-M foam systems: aluminum phosphinate and a brominated polybutadiene-polystyrene copolymer. Evolved-gas analysis (EGA) techniques such as thermogravimetric analysis with mass spectrometry (TGA-MS) and pyrolysis gas chromatography mass spectrometry (PyGCMS) were used to characterize degradation species as well as the FR mechanistic action to reduce the flammability of C-M foams.