Matrix–particle interactions in catalyzed and uncatalyzed copper-filled epoxy matrix composites

Abstract

Epoxy composites filled with copper particles with sizes of the order of 100 μm are studied with the aim of analyzing the particle–matrix interphase. Two matrixes are used: diglycidyl ether of bisphenol A resin (DGEBA)–anhydride catalyzed using a tertiary amine, and uncatalyzed DGEBA–anhydride. The surface of both types of composites was analyzed using scanning electron microscopy, X-ray photoelectron spectroscopy, and instrumented nanoindentation. The formation of Cu(I) and Cu(II) complexes is revealed using X-ray photoelectron spectroscopy, while instrumented nanoindentation measurements allow us to determine regions with different mechanical properties in the uncatalyzed composite. The influence of anhydride and the type of curing reaction on the formation of copper complexes is analyzed. The main results point out that copper particles can interact strongly with the epoxy, depending on the chemistry and kinetics of the curing reaction, to modify the composite.