Novel bio-based epoxy resins from eugenol as an alternative to BPA epoxy and high throughput screening of the cured coatings

• Published in: Polymer (Guilford) 2021-10, Vol.233, p.124191, Article 124191
• Main Authors: Kalita, Deep J., Tarnavchyk, Ihor, Chisholm, Bret J., Webster, Dean C.
• Format: Article
• Language: English
• Subjects: Bio-based; Bisphenol A; Brittleness; Cationic polymerization; Coatings; Curing; Ductile-brittle transition; Epoxidation; Epoxy; Epoxy compounds; Epoxy resins; Eugenol; Glass transition temperature; Hardness; High temperature; High-throughput screening; Monomers; Structure-property; Temperature; Thermoset; Transition temperatures; Vinyl ethers
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2021.124191

A novel vinyl ether monomer from eugenol, 2-eugenoloxyvinyl ether (EEVE), was synthesized and used as a building block for polymeric epoxy resins. The EEVE monomer was polymerized via cationic polymerization of the vinyl ether group leaving the allylic functionality of eugenol available for further epoxidation. Epoxidized poly(EEVE) resins varying in levels of epoxidation (epoxy equivalent weights from 360 to 870 g/eq) were produced and cured with twelve amine curatives at ambient and elevated temperatures for different time intervals to evaluate and optimize the curing regime. The cured coatings were screened with high throughput dye extraction and “conventional” coating testing methods and compared to coatings produced from diglycidyl ether of bisphenol-A (DGEBA). Results showed that coatings derived from epoxidized poly(EEVE) [Epoly(EEVE)] can be tuned from soft and elastic with hardness 60 °C by varying the extent of epoxidation and the nature of curative, whereas DGEBA resulted in hard and brittle coatings irrespective of the type of curative used in the study. Compared to DGEBA resin, coatings with similar or higher crosslink densities and hardness were obtained from Epoly(EEVE) resins with >50% epoxidation of EEVE moieties using the same curative and curing regime. These partially biobased epoxy compounds derived from eugenol have the potential to be competitive with petroleum-based DGEBA resins in coatings applications. [Display omitted] •A novel vinyl ether monomer and linear polymer from eugenol is described.•Eugenol-based epoxy resins are synthesized via controlled epoxidation of allyl groups.•Crosslinked networks can be formed by reacting with different amine curatives.•High-throughput dye extraction is used as a tool for screening X-link density.•Cured coatings from the eugenol polymer and BPA-based epoxy resins show similar performance.