Synthesis, Characterization, and Cross-Linking Strategy of a Quercetin-Based Epoxidized Monomer as a Naturally-Derived Replacement for BPA in Epoxy Resins

• Published in: ChemSusChem 2016-08, Vol.9 (16), p.2135-2142
• Main Authors: Kristufek, Samantha L., Yang, Guozhen, Link, Lauren A., Rohde, Brian J., Robertson, Megan L., Wooley, Karen L.
• Format: Article
• Language: English
• Subjects: Anhydrides; Benzhydryl Compounds - chemistry; Biological Products - chemistry; biomass; Bisphenol A; Bisphenols; Chemistry Techniques, Synthetic; Crosslinking; Epoxy Compounds - chemical synthesis; Epoxy Compounds - chemistry; Epoxy Resins - chemistry; Ethers; materials science; Mechanical Phenomena; Mechanical properties; Monomers; Networks; Phenols - chemistry; quercetin; Quercetin - chemistry; renewable resources; sustainable chemistry; Temperature; Thermal properties
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201600392

The natural polyphenolic compound quercetin was functionalized and cross‐linked to afford a robust epoxy network. Quercetin was selectively methylated and functionalized with glycidyl ether moieties using a microwave‐assisted reaction on a gram scale to afford the desired monomer (Q). This quercetin‐derived monomer was treated with nadic methyl anhydride (NMA) to obtain a cross‐linked network (Q‐NMA). The thermal and mechanical properties of this naturally derived network were compared to those of a conventional diglycidyl ether bisphenol A‐derived counterpart (DGEBA‐NMA). Q‐NMA had similar thermal properties [i.e., glass transition (Tg) and decomposition (Td) temperatures] and comparable mechanical properties (i.e., Young's Modulus, storage modulus) to that of DGEBA‐NMA. However, it had a lower tensile strength and higher flexural modulus at elevated temperatures. The application of naturally derived, sustainable compounds for the replacement of commercially available petrochemical‐based epoxies is of great interest to reduce the environmental impact of these materials. Q‐NMA is an attractive candidate for the replacement of bisphenol A‐based epoxies in various specialty engineering applications. A natural solution: A diglycidyl monomer prepared in two steps using a natural polyphenolic starting material, quercetin, is reacted with nadic methyl anhydride to afford epoxy cross‐linked networks. The thermal and mechanical properties of these networks are compared to similarly synthesized bisphenol A‐based epoxy materials for potential replacement in advanced engineering applications.