Sustainable biobased epoxy thermosets with covalent dynamic imine bonds for green composite development

The widespread use of thermoset composites has raised great environmental and economic awareness, due to the lack of recyclability of the resins and fibres. This work is focused on the development of a sustainable, recyclable and reprocessable epoxy vitrimer by using an epoxidized linseed oil resin and a vanillin derived Schiff base as dynamic hardener. Different epoxy:dynamic hardener ratios have been employed, analyzing its influence in the final physico-chemical properties of the thermoset resin. The reprocessability and the recyclability of the vitrimers have been demonstrated. This work also describes the manufacturing and characterization of greener composites obtained with these vitrimers and flax yarn fibres. A good adhesion between the fibres and the vitrimer is observed. Moreover, the characterization of developed composites indicated that their thermal and mechanical properties allow their use in lightweight engineering applications. Finally, chemical recyclability and compostability of the flax fibre vitrimer-based composite have been demonstrated.

Automated summary

In this study, a sustainable epoxy vitrimer was developed and successfully applied to the production of greener composites. The vitrimer showed good reprocessability and recyclability, as well as good adhesion with fibers. The resulting composites exhibited excellent thermal and mechanical properties for lightweight engineering applications. Additionally, the chemical recyclability and compostability of the composites were demonstrated.