Curing of multicomponent thermoreactive binders in the presence of surfactant highly dispersed particles of a nanodiamond soot

Abstract

The effect of a nanodiamond soot on the conditions and mechanism of cure of epoxy binders is studied for the systems Epikote 828-isomethyltetrahydrophthalic anhydride and Epikote 828-Epikote 154-isomethyltetrahydrophthalic anhydride-endic anhydride-undecylimidazole with the use of a combination of physicochemical methods. The distribution of nanosized particles in the cured epoxy matrixes containing various amounts of the filler is investigated via small-angle X-ray scattering. High-temperature FTIR spectroscopy studies show that the nanodiamond soot catalyzes the curing of the epoxy binders and gives rise to polyester as a reaction product. For the mixture of epoxy resins cured by anhydrides, addition of the nanodiamond soot entails an increase in the conversion of anhydride groups of the binder. In this case, the amount of polyester as a reaction product does not change. This circumstance may be explained by the interaction of the curing agent (isomethyltetrahydrophthalic anhydride and endic anhydride) with the active surface of the soot and epoxy groups of the binder and by the accompanying formation of transition complexes. As a result of this interaction, the rheological characteristics of the composite change: During long-term storage of the epoxy binder without any filler, its viscosity increases and the addition of the diamond charge stabilizes the system.