“Rigid-Flexible” structured polyimine/graphite felt composites with excellent fire Resistance, electromagnetic shielding and recyclability

[Display omitted] •Sustainable development: biobased polyimine is reprocessable, degradable and recyclable.•High performance polyimine: tensile strength (∼85 MPa), toughness and transparency (T = 87.3 %).•Polyimine/graphite felt composites: EMI sheilding of 46 dB and GF recyclability.•Fire Safety: great thermal stability and flame retardancy. With the development of the electronic information, the conductive polymers with high electromagnetic interference (EMI) shielding effectiveness has become a research point. The polyimine material that forms a cross-linking network can rapidly achieve bond exchange at high temperatures, which is becoming a potential substrate for carbon loaded materials. In this work, a novel composite material is successfully prepared by incorporating cost-effective graphite felt (GF) with excellent electrical properties into a biobased polyimine network. Leveraging the exchange properties of dynamic imine bond (−C=N-), the two substrates can be separated by acidolysis, enabling a recycle of the GF efficiently. The electromagnetic shielding effectiveness (EMI SE) of the composite material in the X-band (8.2–12.4 GHz) reaches approximately 46 dB. Additionally, the introduction of highly fire-resistant graphite material significantly enhances the flame retardancy of the composite by reducing the peak heat release rate (HRR) by 47.1 %, which improves the fire safety in complex electromagnetic environments. Herein, we broaden the application of polyimine/graphite composites in the electronic information field and provide a new strategy for the preparation of environmentally friendly composite materials.