Tannic acid based bio‐based epoxy thermosets: Evaluation of thermal, mechanical, and biodegradable behaviors
Nobomi Borah, Niranjan Karak
Abstract
Abstract This scientific paper emphasizes the synthesis of a bio‐based tannic acid epoxy (TAE100) with high bio‐content obtained by simple surface modification of tannic acid (TA). The resin was further cured with a biobased hardener poly(amido amine). Three contrast epoxy resins were also prepared with 50%, 75%, and 90% TA along with the rest amount of bisphenol A (BPA). Upon investigating mechanical properties, TAE100 exhibited a maximum tensile strength of 18.4 MPa (against 3.1–15.3 MPa for partially bio‐based ones) with 16% of elongation at break (against 39.1%–63.5% for partially bio‐based ones). The high adhesive strength (4545 MPa) obtained for TAE100 (compared to 881–2715 MPa for partially biobased ones) on wood‐wood surfaces reflecting good adhesive character of the bio‐based epoxy and offered potential applicability in the field of eco‐coatings and adhesives. Two‐stage thermal degradation behavior with initial decomposition temperature of 232°C revealed its good thermostability. Most importantly, the thermosets were biodegradable, as indicated by the microbial test.