Fully Bio‐Based Epoxy Thermoset Based on Epoxidized Linseed Oil and Tannic Acid

Abstract Increasing demand for bio‐based epoxy thermoset alternatives has risen in the last few years. Epoxidized vegetable oils (EVO) have attracted significant attention due to their bio‐based, unharmful nature and high availability. This study proposes a fully bio‐based epoxy thermoset based on epoxidized linseed oil (ELO) and tannic acid (TA). TA allows, with its high degree of functionality and aromatic structure as a curing agent for ELO, to create a fully bio‐based polymer network with a high glass transition temperature ( T g ), high stiffness, and high strength. A maximum T g of 146 °C, a flexural modulus of 2986 MPa, and flexural strength of 72 MPa are obtained. The strong material properties of the TA/ELO thermoset expose its potential as a bio‐based substitute for petrochemical‐based epoxy resins for high‐performance applications.