Enhancing toughness, healing and reprocessability of sustainable epoxy vitrimer composites by PEG-assisted regenerated cellulose.

• Smaller RC was prepared by PEG-assisted co-precipitation using softwood pulp. • RC were successfully used to prepare vitrimer composites via PEG-assisted strategy. • The epoxy vitrimer composite with both toughness and reprocessability was obtained. • The appropriate RC significantly improved the mechanical properties of composites. • Recyclable polysaccharides-modified composites have industrial application prospects. Sustainable and high-performance thermoset composites have recently drawn extensive attention in industry and academia. Herein, we report an epoxy vitrimer composite with excellent recyclability and mechanical properties reinforced with regenerated cellulose (RC). The RC filler was prepared from natural softwood pulp and integrated into the composites based on a PEG-assisted strategy. The innovative introduction of polyethylene glycol (PEG) effectively realizes the refinement and dispersion of filler. Compared with RC (labeled as RC-SP) prepared by direct precipitation, the average particle size of RC (labeled as RC-P) obtained by co-precipitation with PEG as a template decreases from 66.9 μm to 12.6 μm. An appropriate amount of RC-P significantly improves the mechanical properties of epoxy vitrimer composites in terms of tensile strength, flexural strength, and impact strength, indicating that the toughness has been well improved. In addition, the synergistic addition of PEG and RC-P also endows epoxy composites with improved scratch healing and reprocessability. The reason may be that the abundant hydroxyls of RC-P provide active sites for interface exchange in the epoxy-anhydride system based on transesterification. The effective application of regenerated polysaccharides in vitrimer provides new opportunities for the industrial application of sustainable vitrimer composites. [ABSTRACT FROM AUTHOR]