A Study of Phosphorus–Nitrogen-Containing Modifier with Polyfunctional Action in Polymer Systems

The paper is devoted to the development of a new phosphorus–nitrogen-containing fire retardant with multifunctional action, which is a product of the interaction of dimethylphosphite and dicyandiamide (DDP). The resulting product has a close-to-optimal ratio of nitrogen and phosphorus atoms, which determines its adhesive, thermal stabilizing, and antipyretic activity. DDP has a positive effect on the fire- and heat-protective properties of the material: the time for heating the unheated surface of the sample to 100°C increases by 39–57%, and the linear burning rate decreases by 17–21%. It has been shown that the strength of the adhesive joint increases by an average of 30–70% and the composition containing DDP exhibits consistently better adhesive strength than the original adhesive composition up to 80°C.