IRON(III)-AMINE COMPLEX AS A NEW FLAME RETARDANT-HARDENER FOR EPOXY COMPOSITE MATERIALS

Abstract

A new chelate Fe(III)-amine complex, characterized by its pronounced bifunctional properties as a flame retardant-hardener for epoxy resins, has been synthesized. This complex was synthesized through the rationalization of well-known methods for the synthesis of complexes, which involved the direct interaction of Fe(III) oxide with polyethylenepolyamine. A series of novel epoxy composites, each with distinct flame retardant composites, were synthesized by incorporating the Fe(III)-amine complex into an epoxy diane oligomer. Comprehensive studies have been carried out to evaluate the effect of the Fe(III)-amine complex on the main indices for characterizing the fire hazard of epoxy composite materials. In particular, experimental findings have demonstrated that the ignition of epoxy-amine composites modified with a Fe(III)-amine complex is significantly complicated by the chelation of Fe(III) oxide with a nitrogen-containing hardener of epoxy resins. This effect is reflected in a multiple increase in their ignition and self-ignition temperatures. The findings of the study indicate a decrease in the combustibility of epoxy polymeric materials in the presence of a Fe(III)-amine complex. This decrease is evident in the determination of the maximum temperature of gaseous combustion products, the time to reach the maximum temperature of gaseous combustion products, and the mass loss during combustion. This behavior of the obtained polymer materials is primarily due to the increase in the consumption of thermal energy for breaking Fe–N bonds, which is accompanied by a decrease in the intensity of polymer gasification and an increase in the yield of carbonized residue. The efficacy of the synthesized flame retardant-hardener in epoxy polymers is attributable to its beneficial effect on the reduction of the optical density of smoke emitted during the combustion and smoldering of the composites. The synthesized flame retardant-hardener has also been observed to contribute to the formation of a dense protective layer of a carbonized residue on the surface of the epoxy composite.