Segregated poly(disulfide)@MXene composites with ultralow electrical percolation and chemical recyclability

Abstract

Achieving high electrical performance in polymer composites typically requires high filler loadings, which increases materials costs, complicates processability, and compromises both flexibility and recyclability. Here, chemically recyclable poly(disulfide)@Ti3C2Tx MXene composites with an exceptionally low percolation threshold are developed via electrostatic self-assembly and compression molding. A segregated network is formed by assembling negatively charged Ti3C2Tx MXene nanosheets onto positively charged poly(disulfide) particles, facilitating the formation of continuous conductive pathways at interparticle interfaces. This architecture enables an ultralow percolation threshold of 0.063 vol%, electrical conductivity up to 1.78 x 10(3) S m(- 1), and absorption-dominated electromagnetic interference (EMI) shielding effectiveness of 83.9 dB at 3.8 vol% MXene. The segregated structure also enhances the mechanical properties of the composites including modulus, strength, and toughness. Furthermore, the poly(disulfide) matrix, composed of five-membered cyclic disulfide monomers, undergoes complete depolymerization under mild catalytic conditions, allowing for chemical recycling of monomers, crosslinkers and MXene fillers. This approach offers a generalized pathway toward high-performance, sustainable EMI shielding materials with tunable electrical, mechanical properties, and recyclability.