Sustainable fabrication of closed-loop recyclable aramid paper with enhanced mechanical and breakdown strength

Aramid paper, as a high-performance specialty paper, has attracted significant attention in the fields of national defense, military industries, and aerospace. However, its insufficient interfacial bonding strength and limited heat resistance substantially restrict its broader application. Herein, a series of modified poly(m-phenylene isophthalamide) (SPMIA) polymers were synthesized by introducing sulfonic acid groups (-SO₃H) into the molecular chains. The modified polymer was subsequently processed into precipitated fibers, which were then blended with chopped fibers and fabricated into paper via wet-forming and hot-pressing. During the wet‑forming and hot‑pressing of precipitated fibers and chopped fibers, the abundant sulfonic acid and amide groups form a stronger and denser hydrogen‑bond network. The resulting original paper exhibited a tensile strength of 72 MPa, a breakdown strength of approximately 101 kV/mm, and significantly enhanced thermal stability, with a char residue of about 32 % at 700°C. More significantly, the structural design of the precipitated fiber polymer structure enables the resulting paper to undergo multiple cycles of dissolution, fiber recovery, and paper re-preparation.Importantly, the prepared aramid paper achieved three efficient dissolution-regeneration cycles, with no significant decline in the tensile strength or breakdown strength of the regenerated paper, and the intrinsic viscosity of the solution for redissolving paper remained stable, demonstrating excellent potential for SPMIA paper recycling and reuse. This study provides a novel strategy and methodological foundation for developing green and sustainable high-performance aramid paper materials.