Open Access

Bastian Hahn, Gerd Wehnert, Elisabeth Schamel, Dominik Söthje

• Epoxy resins exhibit good mechanical and thermal properties. Most commercially available epoxy resins rely on fossil resources, which is why research is being conducted on the synthesis of bio‐based alternatives. Although many scientists dealt with new bio‐based epoxy resins, there are still only a few publications on new bio‐based amine curing agents. Vanillin is a promising substance for the synthesis of amine curing agents due to its aromatic structure in combination with its potential bio‐origin from lignin. In this article, the synthesis of 3‐amino‐4,5‐dimethoxy‐benzylamine (ADBA) from vanillin and its use as a novel curing agent for epoxy resins is presented. The synthesis comprises four stages: nitration of the aromatic compound vanillin, methylation of the phenolic group, conversion of the aldehyde into an oxime, and hydrogenation to form the diamine. The diamine can be synthesized with a total yield of 51 wt% and a bio‐content of 74 wt%. According to DSC, the new hardener with diglycidyl ether of bisphenol A (DGEBA) shows aEpoxy resins exhibit good mechanical and thermal properties. Most commercially available epoxy resins rely on fossil resources, which is why research is being conducted on the synthesis of bio‐based alternatives. Although many scientists dealt with new bio‐based epoxy resins, there are still only a few publications on new bio‐based amine curing agents. Vanillin is a promising substance for the synthesis of amine curing agents due to its aromatic structure in combination with its potential bio‐origin from lignin. In this article, the synthesis of 3‐amino‐4,5‐dimethoxy‐benzylamine (ADBA) from vanillin and its use as a novel curing agent for epoxy resins is presented. The synthesis comprises four stages: nitration of the aromatic compound vanillin, methylation of the phenolic group, conversion of the aldehyde into an oxime, and hydrogenation to form the diamine. The diamine can be synthesized with a total yield of 51 wt% and a bio‐content of 74 wt%. According to DSC, the new hardener with diglycidyl ether of bisphenol A (DGEBA) shows a gradual curing reaction due to the presence of an aliphatic and an aromatic amine. Glass transition temperatures (Tg) of 135°C were determined via DMA when using ADBA, which is comparable to that of DGEBA cured with IPDA.…