Functionalized Oligoaryloxycyclotriphosphazenes and Noncombustible Binders Based on Them

Carboxyl-containing aryloxycyclotriphosphazene (I) has been used for curing the ED-20 epoxy resin or a phosphazene-containing epoxy oligomer. In the case of ED-20, curing occurs in the range of 125‒220°C and is accompanied by an exothermic effect that increases from 26 to 50 J/g with an increase in the amount of aryloxycyclotriphosphazene (I) from 25 to 50%. The curing of the phosphazene-containing epoxy oligomer occurs in the temperature range of 140–240°C and is accompanied by an endothermic effect (−Δ H = 6.5–6.8 J/g). Cured compositions based on ED-20 + I are self-extinguishing (flammability class V‑1 according to UL-94), and phosphazene-containing epoxy oligomer + I compositions are noncombustible (class V-0 according to UL-94) regardless of the ratio of the initial components.