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Both environmental and economic factors have driven the development of degradable resin for carbon fiber (CF) recycling under mild conditions. However, the vast majority of thermosetting materials are difficult to recycle. This paper presents bio‐based polyimine vitrimers to fully recycle the CF. The effect of vitrimers fine structures on the thermal, mechanical, solvent resistance, and degradation properties is carefully investigated. The tensile strength at break and Young's Modulus of pure polyimine vitrimers reach ≈80.3 MPa and 2.89 GPa. Importantly, the mechanical property of isophoronediamine‐based polyimine vitrimers/two‐layers CF exhibits a slightly inferior value to that of bisphenol A epoxy. Polyimine vitrimers are easily degradable under acid solution at 60 °C for 24 h. The surface morphology and chemical structure of CF are not changed after recycling. This work on mildly degradable polyimine vitrimers from vanillin and readily recycling of CF is desirable for the development of eco‐friendly CF composites and lignin functional materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chemically Recyclable vanillin based epoxy vitrimers were achieved. • The mechanical properties were comparable to those of Bisphenol A epoxy/CF composites. • Carbon fiber could be recycled at 25 °C for 2 h under 0.1 M HCl/DMF (v/v = 1/1) • The surface morphology and chemical structure of carbon fiber are not changed. Fabrication of recyclable and reprocessable epoxy vitrimers is opening more application opportunities for carbon fiber (CF) recycling. Despite the extensive study of epoxy thermosets from lignin-based monomer of vanillin, however, few works have been focused on its vitrimers, let alone their mechanical, interfacial, solvent resistance and fully recyclable properties of vanillin-based epoxy vitrimers /CF composite. Here the effect of four types of curing agents on the above properties has been carefully studied. Two-layer CF reinforced vanillin-based epoxy vitrimers composites that was cured with Isophoronediamine shows higher tensile strength at break and Young's Modulus than those of Bisphenyl A epoxy (E51)/CF and other epoxy vitrimers/CF composites, which reaches 571 MPa and 11.7 GPa, respectively. All vanillin-based epoxy vitrimers are easily degradable at room temperature in acid solution except for that cured with 4,4′-Diaminodiphenylmethane. The surface morphology and chemical structure of CF are not altered after degradation. Importantly, completely recyclable vanillin-based epoxy vitrimers are achieved by imine exchange reaction; however, the mechanical and thermal properties of it are slightly inferior to the origins. This work demonstrates that the mildly degradable, fully recyclable vanillin-based epoxy vitrimers and readily recycling of CF are desirable for the development of lignin based functional materials. [ABSTRACT FROM AUTHOR]