Researchers from the The University of Naples Federico II have developed a fully bio-based epoxy resin with enhanced adhesive properties, providing a sustainable alternative to BPA-based resins. BPA, commonly used in epoxy resins, has been associated with health concerns, leading to a demand for eco-friendly alternatives. Compared to traditional resins the bio-based epoxy demonstrated higher ultimate strain, slightly lower glass transition temperature, tensile modulus, and ultimate strength. Most notably, it exhibited outstanding adhesive strength on joints, surpassing its BPA-based counterpart by three times. This development offers a sustainable solution for high-performance adhesive applications, meeting safety and technical requirements while reducing environmental impact. Their research was published in the Journal of Materials Science .
Furan-based epoxies: A sustainable solution
Furan-based epoxies, derived from carbohydrates, have emerged as a promising alternative to petroleum-based formulations for adhesive applications. 2,5-bis[(oxiran-2-ylmethoxy)methyl]furan (BOMF), a compound derived from 5-hydroxymethylfurfural (HMF), is one of the most important platform molecules produced from sugars. In previous studies, BOMF-derived epoxy resins have been used for bonding polycarbonate substrates, exhibiting higher tensile-shear strength than petrochemical-based phenyl glycidyl ether.
One of the recent advancements in this field includes the development of a fully bio-based epoxy resin system by curing BOMF with maleic anhydride (MA). MA is easily derived from HMF, making it an environmentally friendly option. The crosslinking process was monitored using differential scanning calorimetry (DSC) and chemo-rheological analysis, and the adhesive properties of the resulting epoxy resin were evaluated on carbon fiber-reinforced thermoset (CFRP) joints.
Advantages of bio-based epoxies
Compared to traditional BPA-based epoxies, BOMF/MA displayed several advantages. It showed a higher ultimate strain, slightly lower glass transition temperature, tensile modulus, and ultimate strength. Additionally, BOMF/MA exhibited outstanding adhesive strength on CFRP joints, outperforming the BPA-based counterpart by three times. This remarkable adhesion strength highlights the potential of furan-based epoxy resins as structural adhesives in various industries.
Furthermore, the development of bio-based epoxy resins addresses the challenges of sustainability in the production of these materials. By replacing BPA, a toxic compound linked to numerous health concerns, with bio-based alternatives, researchers are paving the way for safer, more environmentally friendly adhesive applications in industries such as protective coatings, thermosetting matrices in composites for boating, wind turbines, and aircrafts, and structural adhesives.
Practical applications and future research
With the increasing demand for sustainable and eco-friendly materials, the practical applications of bio-based epoxy resins are vast. From automotive and aviation industries to construction and renewable energy sectors, these epoxies can provide high-performance adhesive solutions while reducing the overall environmental impact. Moreover, the reprocessability of bio-based epoxy resins adds further interest, as demonstrated for thermoset resins derived from epoxidized vegetable oils and itaconic acid.
Although the development of a fully bio-based epoxy resin with enhanced adhesive properties is a significant advancement, further research is required to continue improving the properties and performance of these materials. By exploring new combinations of bio-based compounds and curing agents, scientists can develop even more effective and environmentally responsible adhesives for various industries, contributing to a more sustainable future.
