Vanillin-based polymers: IV. Hydrovanilloin epoxy resins

In this study, hydrovanilloin synthesized by electrochemical dimerization of vanillin has been used as a renewable substitute for bisphenol A for the preparation of epoxy resins. The reaction of the disodium salt of hydrovanilloin:epichlorohydrin 1:2 mol ratio at 80 degrees C for 30 min in water gave a hydrovanilloin - diglycidyl ether phenoxy resin. This hard thermoplastic resin showed T-g of 135 degrees C and stable up to 255 degrees C in air. On the other hand, the disodium salt of hydrovanilloin:epichlorohydrin 1:4 mol ratio at 80 degrees C for 30 min in water gives a curable oligomer of hydrovanilloin - diglycidyl ether with 2.1 repeating units. This oligomer could be cured with aliphatic diamines: 1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, and isophorone diamine to give hard epoxy resins with T-g values of 116, 118, 149 and 146 degrees C, respectively. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47000.