Vanillin‐based polymers: IV. Hydrovanilloin epoxy resins

Abstract

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°C for 30 min in water gave a hydrovanilloin – diglycidyl ether phenoxy resin. This hard thermoplastic resin showed Tg of 135°C and stable up to 255°C in air. On the other hand, the disodium salt of hydrovanilloin:epichlorohydrin 1:4 mol ratio at 80°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 Tg values of 116, 118, 149 and 146°C, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47000.

Recent Research Progress on Lignin-Derived Resins for Natural Fiber Composite Applications

“…EP resin showed outstanding mechanical properties like tensile strength (80.3 MPa) and tensile modulus (2.7 GPa) than the cured DGEBA. Amarasekara and coworkers synthesized the hydrovanilloin epoxy monomer (HVEM) using the electrochemical dimerization of VN, followed by the transformation of epichlorohydrin with NaOH ( Figure 8 c) [ 106 ]. Moreover, the hydrovanilloin epoxy resin (HVER) was prepared by the curing of various aliphatic amines such as 1,2-diaminoethane (1,2-DAE), 1,4-diaminobutane (1,4-DAB), 1,6-diamino hexane (1,6-DAH), and IPDA.…”

Electrochemical synthesis of biobased polymers and polymer building blocks from vanillin

“…in the synthesis of a hydrovanilloin-formaldehyde copolymer 21 or a hydrovanilloin-diglycidyl ether phenoxy resin. 22 Another electrochemical approach exploiting the same reaction type of pinacolization is the synthesis of polyvanillin by reductive polymerization of 6,6 0 -dihydroxy-5,5 0 -dimethoxy-(1,1 0biphenyl)-3,3 0 -dicarboxaldehyde, commonly called divanillin or 5,5 0 -bis-vanillin (Scheme 2). The feasibility of this synthesis was shown by Amarasekara et al in 2012 at a lead cathode in 1 M sodium hydroxide solution leading to a total vanillin-based polymer.…”

Vanillin based polymers: V. Poly(hydrovanilloin–urethane)

“…29 In a more recent effort we have shown that hydrovanilloin synthesized by electrochemical dimerization of vanillin can be used as a renewable substitute for bisphenol A for the preparation of epoxy resins. 30 The reaction of equivalent amounts of the disodium salt of hydrovanilloin with epichlorohydrin gave a hydrovanilloin–diglycidyl ether phenoxy resin with Tg 146°C. On the other hand, two equivalents of epichlorohydrin with hydrovanilloin gave a curable oligomer of hydrovanilloin–diglycidyl ether with 2.1 repeating units.…”

“…Furthermore, this oligomer could be cured with various aliphatic diamines to give hard epoxy resins with Tg values in the range of 116–149°C. 30…”