Macadamia for robust epoxy coatings
Researchers have described the cationic UV-curing of an isosorbide-based epoxy coating reinforced with macadamia nut shell powder.
The development of bio-based plastic is one of the main challenges that needs to be overcome to achieve the goal of sustainability and green economy. Reseachers now have exploited the use of a bio-based monomer, isosorbide, for the production of bio-based resins which can be used in coating applications. The isosorbide was functionalised in a two-step reaction to introduce epoxy groups that subsequently were activated via UV radiation to trigger cross-linking to obtain dry films.
Significant increase in hardness
Furthermore, a bio-based filler from macadamia nutshell was selected as an additive to the formulation with the aim of increasing the surface hardness of the final coating. A significant increase in hardness was observed for coatings containing 30 wt% of macadamia nut shell powder (MAC). In this case, the hardness reached 72 Shore D, whereas the pristine bio-based epoxy resin achieved only 19 Shore D. Interestingly, the addition of MAC also resulted in a noticeable increase of the Tg, from 24 °C for the pristine resin to 39 °C for the coating with 20 wt% of filler.
The study has been published in Progress in Organic Coatings, Volume 185, December 2023.
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