Self-Healable and Recyclable Bio-Based Crosslinked Polyimide Hybrid Dielectrics Enabled by Molecular Chain Tailoring

Growing environmental concerns about petrochemical plastics are driving the need to explore green and sustainable alternative materials. Polyimide (PI), as a typical petrochemical material, has a unique ordered molecular structure and tightly entangled molecular chains, making it difficult to heat form, and the recycling back to their original form is virtually impossible after damage. To overcome these obstacles and create next-generation sustainable dielectrics, a strategy to realize the partial disassociation and reassembly of imine bonds in PI via constructing a dynamic covalent network is proposed, thereby endowing PI hybrid dielectric with self-healable and recyclable abilities. In this case, the dynamic covalent network is achieved by polymerization of a bio-based crosslinker with PI oligomers. Therefore, the film has an excellent self-healable and polymer-monomer recyclable capability after electrical or mechanical damage. Furthermore, the carbon fiber reinforced composites (CFRCs) formed by film precursor and carbon fibers (CFs) also have a non-destructive recovery rate of up to 100%. This high-performance, reusable, bio-based crosslinked PI hybrid dielectric provides a prime example of an advanced sustainable insulating dielectrics.