Sustainability and repeatedly recycled epoxy-based vitrimer electromagnetic shielding composite material

Abstract

A series of electromagnetic interference (EMI) shielding composites composed of an epoxy-based vitrimer matrix and stainless-steel fabric was prepared in this study. The polymer matrix presents tunable mechanical properties and chemical recyclability through adjustment of the content ratio of soft aliphatic sebacic acid (SA) to rigid crosslinker 3-(carboxymethyl)cyclopentane-1,2,4-tricarboxylic acid (TCAA). All the recycled vitrimers exhibit strengths comparable to the original materials, suggesting that similar cross-linking structures were reformulated successfully. Furthermore, a noticeable enhancement in the mechanical strength is observed for the combination of matrix and stainless-steel fabric, indicating that the combination of vitrimer material and fabric is excellent. However, a certain extent of decreased mechanical abilities was observed for the composites after reclaiming, while no apparent differences are noted in the results between multiple recycling processes. This tendency may be attributed to the complex fabric structure, which allows a distinct distribution for the reclaimed matrix that is repolymerized by evaporating the solvent compared to the original polymer. In addition, the original and repeatedly recycled composites reveal comparable EMI shielding abilities of around 70 dB, demonstrating the potential for high performance when applied as EMI shielding materials.