Syringaresinol: A Renewable and Safer Alternative to Bisphenol A for Epoxy‐Amine Resins

Abstract

A renewable bisepoxide, SYR-EPO, was prepared from syringaresinol, a naturally occurring bisphenol deriving from sinapic acid, by using a chemo-enzymatic synthetic pathway. Estrogenic activity tests revealed no endocrine disruption for syringaresinol. Its glycidylation afforded SYR-EPO with excellent yield and purity. This biobased, safe epoxy precursor was then cured with conventional and renewable diamines for the preparation of epoxy-amine resins. The resulting thermosets were thermally and mechanically characterized. Thermal analyses of these new resins showed excellent thermal stabilities (T =279-309 °C) and T ranging from 73 to 126 °C, almost reaching the properties of those obtained with the diglycidylether of bisphenol A (DGEBA), extensively used in the polymer industry (T =319 °C and T =150 °C for DGEBA/isophorone diamine resins). Degradation studies in NaOH and HCl aqueous solutions also highlighted the robustness of the syringaresinol-based resins, similar to bisphenol A (BPA). All these results undoubtedly confirmed the potential of syringaresinol as a greener and safer substitute for BPA.

Microwave-Assisted Knoevenagel-Doebner Reaction: An Efficient Method for Naturally Occurring Phenolic Acids Synthesis

“…The industrial interest for naturally occurring PAs is increasing due to the emergence of promising ferulic- and sinapic-acid–based functional additives [e.g., bisphenol A substitutes (Jaufurally et al, 2016 ; Janvier et al, 2017 ), antioxidants (Reano et al, 2015 , 2016b )], anti-UV molecules (i.e., sinapoyl malate), (Allais et al, 2009 ; Dean et al, 2014 ; Luo et al, 2017 ) and renewable polymers and resins (Kreye et al, 2013 ; Ouimet et al, 2013 ; Barbara et al, 2015 ; Pion et al, 2015 ; Hollande et al, 2016 ; Maiorana et al, 2016 ; Reano et al, 2016a ; Menard et al, 2017 ; Nguyen et al, 2017 ). Encouraging works have been conducted for the biosourcing of PAs.…”

Synthesis and curing properties of castor oil‐based triglycidyl ether epoxy resin

“…As the temperature rose, the frozen segment structure began to relax, so that the storage modulus of the splines decreased 31 . On account of the long flexible chain structures which improved the chain sliding ability of the curing systems, the molecular chain of the curing component required less energy to relax, and the corresponding tanδ peaks temperature (T g ) were lower than that of neat E‐51, representing the glass transition temperature decreases 32 . All tan δ curves show a peak, indicating excellent compatibility of the hybrid curing system.…”

Bisphenol A: A Concise Review of Literature and a Discussion of Health and Regulatory Implications

“…The full extent of their effects is difficult to predict, and what we have determined is highly suggestive of an increased risk of human oncogenesis, including breast cancer. It would be imperative to phase out BPA from use in the manufacture of consumer and healthcare goods in favour of safer alternatives (25).…”

“…For example, syringaresinol has been characterised as a renewable and safer alternative to BPA in the manufacturing of epoxy resins. Such alternatives make the phasing out of BPA from consumer goods feasible (25).…”