Preparation of fully biobased epoxy resins from soybean oil based amine hardeners

This work reports a straigthforward method for the preparation of soybean oil based amine derivatives to be used as green hardeners for epoxy resins. The hardeners were synthesized by the Michael-addition reaction of acrylated soybean oil (AESO) with different diamines, viz. 1,6-hexamethylene diamine (HMDA), trans-1,4-cyclohexylamine (TCHMDA) and L-lysine methyl ester hydrochloride (LYS). The reaction proceeded under mild conditions and the products were obtained with high yields. The amine biobased hardeners were successfully crosslinked with ESO, affording soybean oil based thermosets (SOTs). The SOTs were characterized in terms of thermomechanical properties, swelling capacity, in vitro hydrolytic degradation. The results allowed to establish important structure/properties relationships between the materials and methods used and the performance of the SOTs. This work could be used as proof-of-concept to enlarge the vast range of applications that employ amine curing.