Epoxy composites with 10 and 50 wt % micronanoiron: strength, microstructure, and chemical and thermal resistance

Abstract

The strength and resistance of epoxide (ED20 + polyethylenepolyamine)–micronanoiron (R10 or R20) composite systems, which are of interest for machine-building, instrument-making, and aerospace industry, were studied. Introduction of micronanoiron into the epoxy resin allows preparation of iron–epoxy composites without significant changes in the adhesion to steel and in the bending modulus, with only a slight (10–15%) decrease in the compression strength. Filling does not affect the heat resistance of the components (thermal gravimetric analysis) and enhances the flame resistance. The morphology of the composites is characterized by aggregative, relatively uniform distribution of iron particles in the resin. The compression strength increases after heating to 250°С (in contrast to the unfilled polymer). On the other hand, filling slightly weakens the resistance of iron–epoxy composites to aggressive media (with acetone–ethyl acetate mixture and 25% HNO₃ as examples). Surface modification of iron particles with acrylic varnish in some cases enhanced both the swelling resistance (with 10% modified R10 iron in contact with water and 25% HNO₃ as example) and the strength characteristics (with the bending modulus and compression strength after heating to 250°С as example).