Strong and Tough Epoxy Thermosets With Hyperbranched Epoxy Resin via Constructing Sacrificial Multiple Network

To address the issues of low fracture toughness and poor impact resistance of epoxy thermosets, this study synthesized a vanillin-based hyperbranched epoxy resin (VHER) via constructing a sacrificial multiple network. The sacrificial multiple network promotes the stress distribution and effective energy dissipation through bond breaking and recombination, thereby simultaneously enhancing the strength and toughness of epoxy thermosets. The hyperbranched topology regulates crosslinking density, increases free volume, and induces microphase separation. As a result, the epoxy thermosets containing 9% VHER exhibit outstanding overall performance with a tensile strength of 126.26 MPa and toughness of 10.41 MJ·m −3 . This work provides new design strategies and theoretical insights for the development of epoxy thermosets with superior mechanical properties. Highlights Constructing a sacrificial multiple network with hyperbranched epoxy resin for epoxy thermosets. The epoxy network dissipates energy via sacrificial cleavage under external stress. Epoxy thermosets exhibit excellent high strength and toughness without loss in T g .