Synergistic Effects of Nonstoichiometric P–N Flame Retardants Based on Melamine and Ammonium Derivatives of Phosphoric Acid. Part 1. A Literature Review
摘要
This paper presents a review of modern studies in the field of development of synergistic flame retardants based on phosphorus- and nitrogen-containing compounds including melamine, ammonium polyphosphate (APP), derivatives of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and hybrid systems. The mechanisms of their action, such as gas-phase inhibition of radicals, formation of thermally stable carbon layers, and catalytic degradation of polymer matrices, are considered. Special attention is paid to combinations demonstrating synergism, e.g., phosphorus–nitrogen–carbon (P–N–C) systems, nanomaterials (graphene, nanotubes), and metal–organic frameworks (MOFs). It is shown that such compositions significantly increase the fire resistance of polymers (an oxygen index of up to 45%, UL-94 V-0 rated) and decrease heat release and smoke generation without sacrificing mechanical properties. The environmental advantages of halogen-free flame retardants and prospects of their application in epoxide resins, polyurethanes, textile, and composites are discussed.