Tung oil-based modifier strengthening and toughening epoxy resin by sacrificial bond

Epoxy resins, previously toughened using plant oil derivatives, continue to face the challenge of balancing strength with flexibility due to their extensive fatty acid chains. This research introduces a novel approach, utilizing principles observed in nature, such as sacrificial bonds found in spider silk, bones, and nacre, which confer superior strength and resilience. By incorporating sacrificial π-π interactions into the epoxy resin matrix, using modified tung-oil based additives with reduced fatty segments and an enhanced concentration of functional groups, simultaneous enhancement in toughness and strength is achieved. The newly synthesized tung-oil derivative, tung oil-based glycerol monoester dibutyric acid (TOGDA), retains the conjugated trienes of original tung oil, derived from eleostearic acid. Incorporating merely 5 wt% of TOGDA resulted in notable improvements, with increases of 13.0 % in tensile strength and 196.7 % in impact strength relative to pure epoxy resin. The integration of TOGDA via covalent bonds into the curing network significantly augments its compatibility with the epoxy framework. The inclusion of a minor fraction of TOGDA minimally impacts the dynamic thermal mechanical characteristics and the thermal stability of the enhanced resin. This development is crucial for improving the overall performance of brittle thermoset resins by incorporating modifiers derived from plant oils.