Functionalized green tea tannins as phenolic prepolymers for bio-based epoxy resins

• Green tea tannins were functionalized with epichlorohydrin to give epoxy prepolymers.
• Epoxy networks were synthesized by reaction with diamines.
• Cured epoxidized tannins were compared to DGEBA.
• Epoxy networks from tannins showed good mechanical and thermal properties.
• Some thermo-mechanical properties of epoxy networks have been studied.

Phenolic extract from the green tea leaves was used for the production of thermoset epoxy resins. The commercial green tea extract (GTE) was functionalized by the reaction with epichlorohydrin in the presence of phase transfer catalyst. The glycidyl ether derivative of the green tea extract (GEGTE) obtained with a good yield was cured in epoxy polymer with isophorone diamine (IPD) and the resulting network was compared to catechin-IPD and diglycidyl ether of bisphenol A (DGEBA-IPD) systems. The thermal and mechanical analyses of this bio-based epoxy polymer showed its high reactivity associated with a high crosslinking density (Tg: 140–190 °C), a high thermal resistance and interesting mechanical properties.

A bio-based epoxy prepolymer was synthesized from the reaction of a green tea extract with epichlorohydrin in the presence of catalyst. Then, the prepolymer was cured with a secondary amine (isophorone diamine) to provide an aromatic bio-based epoxy resin, which exhibits promising thermal and mechanical properties.Figure optionsDownload as PowerPoint slide