Revealing the Dynamics of Sustainable Epoxy-Acrylate Networks from Recycled Plastics Blends and Oligomeric Lignin Precursors.

The pursuit of carbon circularity in the fabrication of new materials has driven the increased use of recycled and biobased resources, a practice that has become more prevalent in recent years. In epoxy resin systems, alternatives to the use of fossil-based bisphenols have been proposed such as via the production of recycled bisphenol A (r-BPA) or by substitution with lignin derivatives, both of which are recovered from previous processes, promoting circularity. For this study, r-BPA was obtained via the chemical recycling of plastic blends from end-of-life (eol) televisions (TV). Subsequent glycidylation with epichlorohydrin (ECH) and ring-opening using acrylic acid allowed to obtain recycled bisphenol A diglycidyl ether (r-DGEBA) and bisphenol A glycerolate diacrylate (r-DAGBA), respectively. Six thermosets were fabricated by reacting Jeffamine D230 (Jeff D230) with r-DGEBA/r-DAGBA in a diverse range of epoxide:acrylate (E : A) ratios. The addition of acrylates resulted in the formation of β-amino esters (via Aza-Michael addition), which are thermo-reversible and allow the incorporation of dynamic bonds into the otherwise robust epoxy formulation. To evaluate the effect of the increasing biobased content, glycidylated depolymerized lignin (GDL) from hardwood was incorporated into the composition to produce five extra polymers. The crosslinked networks of these materials were extensively characterized, and the structure-property relationship was established by comparing their thermomechanical performance. The dissociative acrylate-amine interactions were identified under specific thermal conditions, applied systematically to program temporary shapes and analyse the crosslink reversibility of the thermosets. In summary, our findings demonstrate that recycled and biobased aromatic monomers can be incorporated to create dynamic crosslinked structures with tuneable properties, representing a step forward towards versatile, reusable, and circular materials.