THE USE OF COPPER(II) FLUORIDE TO INCREASE THE THERMAL STABILITY AND FLAME RESISTANCE OF EPOXY-POLYMERS

Abstract

Introduction. Among the extremely wide range of flame retardants, which are used to reduce the combustibility of polymer materials based on epoxy resins, metal compounds deserve special attention. However, mainly, researchers suggest using metallic compounds that are inert to the polymer as flame-retardants. However, taking into account the disadvantages inherent in such flame-retardants, their use is constantly decreasing. Instead, reactive metal-containing flame-retardants are becoming more and more popular, which, due to the presence of functional groups in the molecular structure, interact chemically with the components of epoxy composites. In this aspect, complex compounds of transition metals are quite promising. However, at present, there are practically no systematic studies aimed at disclosure of the consistent effect of such flame-retardants on the structure, and therefore on the properties of the obtained materials. Therefore, research related to the expansion of the range of flame-retardants of this class and the study of their influence on the main parameters, which are used to evaluate the propensity to ignition and burning of polymer materials, are extremely relevant.
Purpose. The purpose of the work is an experimental study of the influence of copper (II) fluoride on the course of thermos-oxidative destruction and the susceptibility to the ignition of polymer materials based on epoxy-amine composites.
Methods. The behaviour of the obtained epoxy polymers under the conditions of thermo-oxidative destruction was studied by the method of derivatography. To characterise the resistance of epoxy-polymers to ignition and self-ignition, the ignition and self-ignition temperatures were determined following DSTU 8829:2019.
Results. The results of derivatographic studies testify to the intensity of thermo-oxidative destruction of polymers based on epoxy-amine composites modified with copper (II) fluoride is significantly lower than that of polymers based on unmodified composition. In addition, the combustion of pyrolytic residues of the organic component of the polymer based on the modified composite occurs in a limited temperature range, which is indisputable evidence of the selfextinguishing effect of the combustion of the copper-containing polymer. The highest resistance to ignition and selfignition is characterized by a composite with a content of 40 mass parts CuF2 per 100 mass parts binder; its ignition temperature is 21ºC higher compared to the unmodified composition, and the self-ignition temperature is 33ºC higher.
Conclusion. The use of copper (II) fluoride as a flame retardant leads to an increase in the thermo-oxidative stability and resistance to the ignition of epoxy polymers. This effect is achieved due to the formation of strong coordination bonds that arise between the d-metal salt and the amine-hardener of epoxy-resins in the process of spatial crosslinking of the epoxy-amine composite. As a result, the rate of destruction of the polymer is significantly reduced, since additional energy must be spent on the destruction of newly formed bonds. As a result, this affects the decrease in the intensity of the formation of volatile combustible products of polymer decomposition and their diffusion into the combustion zone, due to which the rate of their oxidation decreases.