Metal-Coordinated Epoxy-Amine Composition with Reduced Fire Risk: Elaboration, Thermal and Ignition Resistance

Abstract

A new flame retardant-hardener for epoxy resins has been prepared. The flame retardant-hardener is a coordination compound of a chelate type, aqua-bis(ethylenediamine)-chloro-copper(II) chloride, [Cu(eda)₂(H₂O)(Cl)]Cl (eda – NH₂C₂H₄NH₂). The incorporation of the flame retardant curing agent, [Cu(eda)₂(H₂O)(Cl)]Cl, into the epoxy polymer matrix results in the production of new generation polymeric materials with reduced fire risk based. Bonding in the [hardener – flame retardant] system involve the interaction of a combustible nitrogen-containing curing agent (ethylenediamine) with a non-combustible inorganic d-metal salt (copper(II) chloride) into an aminocopper(II) chelate compound through strong Cu–N coordination bonds. The strength of bonding between the copper(II) salt and the amine hardener, as well as the participation of the resulting aminocopper(II) chelate compound in the formation of the polymer matrix framework, determine the resistance of modified epoxy-amine compositions to thermal oxidative degradation and ignition. The inclusion of the flame retardant-hardener in the epoxy resin reduces the segmental mobility of the interconnecting molecular links and leads to the creation of a denser polymer matrix. As a result, metal-coordinated epoxy-amine compositions are formed, which display good thermal resistance and self-extinguishing properties under combustion conditions.