Tensile Properties of Epoxy Composites Filled With Graphene Nanoplatelets and PUF Microcapsules

This work evaluates the effect of poly(urea-formaldehyde) (PUF) microcapsules filled with aminated polydimethylsiloxane (PDMS-a), a self-healing agent, on the tensile properties of epoxy composites reinforced with graphene nanoplatelets (GNP). The microcapsules are produced by interfacial polymerization and later are infiltrated with the healing agent (PDMS-a). GNP are dispersed in epoxy resin using sonication, followed by the addition of hollow or filled PUF microcapsules to the system, using mechanical stirring, just before the addition of the curing agent (hardener). The mixture is then cast in soft molds to produce specimens for tensile tests. The results show that the presence of 1 wt% GNP changes the properties of the composites with an improvement in tensile strength and modulus, which achieves 37.4 MPa and 2.8 GPa, respectively, in comparison with neat epoxy and specimens containing just microcapsules. The addition of 2 wt% GNP, however, impairs these properties, with tensile strength and Young's modulus decreasing to 24.9 MPa and 2.3 GPa, due to the presence of GNP agglomerates. The presence of the microcapsules, however, decreases the immediate (no self-healing) tensile performance of the composites. © 2024 Wiley-VCH GmbH.