RATIONAL TECHNOLOGIES FOR PRODUCING METAL-COORDINATED EPOXY-AMINE COMPOSITES WITH REDUCED COMBUSTIBILITY

Abstract

Introduction. Reducing the combustibility of polymeric materials is achieved through the formation of atomic bonds with high breaking energy. For this purpose, chemically active flame retardants are most often used, which, due to their high  reactivity and the presence of a large number of different types of functional groups in the molecular structure, lead to changes in the composition, structure and properties of the final polymeric material. Such flame retardants are used as  monomers in the synthesis of polymers, crosslinking agents or polymer modifiers. Therefore, an extremely important issue in terms of reducing the combustibility of polymers is to expand the range of reactive flame retardants, develop a  rational technology for the production of polymeric materials that provide for various methods of introducing flame retardants, and establish the relationship between the modification, structure and properties of the resulting materials.
Purpose. To develop a rational technology for the preparation of epoxy-amine compositions modified with copper(II) chloride. To study the structure of the synthesised compositions, which will allow predicting their properties and, in particular,  their propensity to burn.
Methods. Epoxy-amine compositions modified with copper(II) chloride were obtained by two methods, the difference between which lies in the different ways and forms of incorporating the flame retardant into the polymer matrix. To establish  the fact of interaction between the flame retardant and other components of the composition (binder, hardener), infrared spectroscopic studies were performed.
Results. A new original method for the preparation of epoxy-amine compositions modified with copper(II) chloride with reduced combustibility has been developed. The essence of the method is the synthesis of a flame retardant-hardener
in the form of a crystalline complex with its subsequent incorporation into an epoxy diane oligomer. As a result of the chemical interaction of copper(II) chloride and pepa, the chelated complex [Cu(eda)2(H2O)(Cl)]Cl was obtained, which was  used as a flame retardant-hardener for epoxy-amine compositions. Based on IR spectroscopic studies, the structure of the synthesised flame retardant-hardener was studied. In particular, strong Cu(II)←N coordination bonds were found, the  appearance of which in the process of complexation is an important prerequisite for the use of the obtained chelate complexes as reactive flame retardants. The participation of the synthesised chelate complex [Cu(eda)₂(H₂O)(Cl)]Cl in the structuring of the epoxy-amine composition was revealed, which is the key to reducing its combustibility.
Conclusions. Thanks to the development of an original technology involving the synthesis of a chelated cupro-amine complex and its use as a flame retardant-hardener, a new type of metal-coordinated epoxy-amine compositions was obtained and the mechanism of the flame retardant effect of transition metal salts on the combustion of epoxy-amine compositions was interpreted.