Highly efficient thermal stability of bio-based rigid polyurethane foam via melamine and its derivatives as additive flame retardant
Bio-based rigid polyurethane foam was synthesized via the reaction of ꞵ-myrcene oil and 2-mercapethonal through UV catalyzed thiol-ene chemistry. Modern polyurethane industries have shown a growing interest in utilizing renewable materials because they have confirmed promising properties without any environmental issues. Polyurethane foam contains porous structures, which probably is the main reason for its flammability. Recently, halogen-free FRs have garnered significant attention, especially nitrogen-based additives to slow down and retard the burning rate or self-extinguish the flame. Melamine and its derivates are the main organic nitrogen chemicals used as additive flame retardants and can be a good choice to be incorporated into the polyurethane foam due to the low toxicity with effective performance in preventing fire propagation. Melamine undergoes strongly endothermic decomposition and acts as a heat sink in a combustion event. Hence, it possesses a higher decomposition temperature and releases nonflammable gases along with forming a char layer on the foam’s surface. Melamine, melamine cyanurate, and melamine phosphate were used as an additive flame retardant in bio-based rigid polyurethane and have been shown to decrease flammability without sacrificing the mechanical integrity of the foam. The neat foam was burnt for 40 s with 40% weight loss, however, the addition of melamine showed a shorter burning time and weight loss for 14 s and 2.5 wt.%, respectively. Melamine Cyanurate behaved producing a flickering fire that self-extinguished in 21 s with 4 wt. % weight loss. In comparison to pure melamine and melamine cyanurate, melamine phosphate showed a better thermal stability and extinguished the fire for 11 s with 3 wt.% weight loss. Therefore, ecofriendly melamine-based materials are capable of suppressing the flame within a short time with a minimum concentration of smoke and toxic gases. As a result, using eco-friendly materials such as myrcene and nitrogen-based FR offered a viable option to improve the physicomechanical and thermal stability of rigid polyurethane foam.
Nejad, Niloofar Arasteh, "Highly efficient thermal stability of bio-based rigid polyurethane foam via melamine and its derivatives as additive flame retardant" (2021). Video Presentations. 34.