Reversible Schiff-base chemistry enables thermosetting smart composites with versatile properties

Abstract

Fibre-reinforced polymer composites have become indispensable structural materials in modern life and global industry due to their superior specific properties and improved energy efficiency. However, the irreversibility of commercially available thermoset matrices, characterized by covalent cross-linking, poses challenges to both the recyclability and the enhancement of functionality. Herein, inspired by living tissues, we demonstrated recyclable, reprocessing, self-growing, and thermally/water modulated carbon fibre reinforced polyimine composites at low processing temperatures (≤110 °C, without any catalyst), realizing the intelligent composites. The tensile strength and average friction coefficients of our composites were 129.1 MPa and 0.52, respectively. Moreover, the chemical welding and self-growing mechanism of our system were deeply explored. The process enabled the recovery of clean and intact carbon fibres. We aim for this work to further deepen the understanding of dynamic polyimine networks with semi-aromatic skeleton, and facilitate the preparation of smart, adaptive and pluripotent composites.