Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Graphene oxide-functionalized hyperbranched polysiloxane is synthesized as a homogeneous toughening agent for epoxy resin. Strong interfacial bonding and synergistic crack-deflection mechanisms markedly enhance tensile strength and impact toughness while maintaining thermal stability. The modified epoxy exhibits improved energy dissipation, ductility, and structural integrity, offering a promising strategy for high-performance epoxy composites.

ABSTRACT
Epoxy resins (EP) have been constrained in their broader application primarily due to their inherent limitations in toughness. Hyperbranched polymers, with their highly branched, three-dimensional architecture, present significant promise and exceptional potential as toughening agents for epoxy matrices. In this study, graphene oxide (GO) functionalized hyperbranched polysiloxane (GHBPSi) was successfully synthesized and introduced as an effective toughening agent for EP. This modification substantially enhanced both the strength and toughness of the EP, while preserving the material's thermal stability. The impact toughness and tensile strength of the EP modified with 2 wt.% GHBPSi were measured at 7.82 kJ/m2 and 30.7 MPa, respectively, representing a remarkable enhancement of 165% and 170% over those of pure EP. Furthermore, the thermal weight loss at 800°C exhibited only a slight decrease, from 93.76% to 91.22%. This novel high-toughness resin material offers a promising approach for the development of polymer composites with superior mechanical properties.