Natural derivatives of diphenolic acid as substitutes for bisphenol-​A

Diphenolic acid had been originally used in the first epoxy resins and was later on forgotten as it was substituted by the cheaper bisphenol A. But in the recent years major health concerns were raised as bisphenol A has a pseudo-​hormonal effect on the body, playing the role of estrogen it can cause a severe impact on the organism, esp. in males. Moreover it is produced from acetone and phenol, both from fossil, and thus limited resources. On the contrary, diphenolic acid is synthesized from levulinic acid and phenol. Levulinic acid being directly produced by hydrolysis of biomass. By substituting the fossil phenol with natural phenols from lignin or plant extn. the authors are able to synthesize a fully renewable substitute for bisphenol A. The reactions to yield an epoxy resin were examd. and the reactivity with epichlorohydrin is satisfying. Moreover, some of the derivs. of diphenolic acid have interesting curing properties and preliminary results show excellent properties of the cured resin, including thermal stability and pencil hardness