STUDY OF THE EFFECT OF HALOGENATED FIRE RETARDANTS ON REDUCING THE FLAMMABILITY OF COMPOSITE REINFORCEMENT

Abstract

The article is devoted to the issue of reducing the flammability of fiberglass composite reinforcement, which is obtained based on an epoxy anhydride binder by the needle extrusion method. The authors applied halogenated epoxy resins based on tetrabromobisphenol A and chlorine-containing resin EHD (N,N-tetraglycidyl-3,3′-dichloro-4,4′-diaminodiphenylmethane) as flame retardant components (modifiers). We controlled the degree of transformation (passage of the polyaddition reaction) of epoxy systems exposed to heat under the technology conditions by the method of sol-gel analysis. The conducted research established the ability of halogenated flame retardants not to exert a directed effect on reducing the flammability of composite reinforcement obtained in the short-term mode of formation. Under these conditions, the composition of the epoxy anhydride binder is of great importance, considering the ratio of epoxy and anhydride groups in the reaction system. We determined that to achieve an increased oxygen index and a relative decrease in the flammability of composite reinforcement in the conditions of a short-term hardening regime, a small addition of flame retardant, which contains only chlorine-containing oligomer EHD, is necessary. In this particular case, we observed a characteristic anti-plasticising effect, which leads to the preservation of the modulus of elasticity of the composite material and a decrease in the flammability of the composite. With a further increase in the amount of the antipyretic modifier, structural transformations occur at the supramolecular level, which possibly prolongs the distance between the mesh nodes of the hardened matrix of the composite and contributes to a decrease in its modulus of elasticity and loss of its ability to inhibit the spontaneous combustion reaction. As a result of the plasticising effect at the supramolecular level, molecules surround the internodal structural elements of the polymer. It leads not only to a decrease in the interaction between the macromolecules of the epoxy polymer but also to an increase in the diffusion characteristics of the entire system. Keywords: fibreglass composite reinforcement, flammability, oxygen index, halogenated fire retardant.