Biosourced alternatives to diglycidylether of bisphenol A in epoxy-amine thermosets: a focus on materials properties and endocrine activity

Since 1940s, bisphenol A (BPA) has been used in plastic industry reaching production of 10 million tons in 2022. More than 30 % of the produced BPA is used in the production of epoxy resins. Decades of research has now provided enough evidence that (BPA) has endocrine disrupting activity. Hence, it is an urgent matter to replace the use of BPA in production of epoxy resins. In the past years, considerable effort have been put into finding alternatives to the toxic BPA. However, the diglycidylether bisphenol A (DGEBA) does not only exhibits high polymerization reactivity, but the presence of aromatic rings confers interesting thermos-mechanical resistance to epoxy networks therefrom. Hence, this properties are also expected from potential alternatives to BPA. In this review, first the elements leading to toxicity of BPA is explained and then a thorough account of possible bio-sourced aromatic alternatives to BPA are gathered. The reported synthetic routes to each of these alternatives and their toxicity are described. Also, their use in synthesis of epoxy resins and how the new alternatives influence the mechanical properties are discussed. This is a concise summary of the structure-property and structure-toxicity relationship for possible bio-sourced substitutes of BPA in synthesis of epoxy resins.