Bioinspired Vine-Wrapped PEEK/PAR Nanocomposite Paper with Hierarchical Interface Coupling for Enhanced Dielectric Strength and Aging Stability

This study presents a high-value green recycling strategy for waste polyetheretherketone (PEEK) to fabricate a bioinspired “vine-wrapping” nanocomposite insulating paper from recycled PEEK fibers and self-prepared polyarylate (PAR) nanofibers. The multiscale synergy of the nanocomposite significantly enhances its dielectric performance. Micron-scale PEEK fibers form a three-dimensional scaffold, which provides mechanical support and carrier transport pathways. High-aspect-ratio PAR nanofibers exploit secondary thermoplasticity to infiltrate scaffold voids, refine pore structures, suppress electric field distortion, and inhibit electrical tree initiation. At the molecular level, strong dipole-dipole interactions between PEEK carbonyls and PAR esters, along with π-π stacking of aromatic rings, create a stable, hierarchical noncovalent interface. Consequently, the PEEK/PAR nanocomposite paper achieves a breakdown strength of 89.67 kV/mm, representing a 256.11% improvement over commercial aramid paper. After thermal aging (200 °C, 24 h), UV exposure (365 nm, 24 h), 100 folding cycles, and 20 kneading-folding cycles, the breakdown strengths remain at 34.14, 37.34, 17.51, and 17.06 kV/mm, respectively. These values are 2.3, 1.91, 1.38, and 2.31 times the strength of commercial aramid paper. These results indicate a viable pathway for developing sustainable, high-performance, paper-based insulation.