Sustainable Recycling of Waste Para-aramid Fabric into Polyarylate Nanofiber Sealed High Performance Insulation Paper

The widespread use of polyphenylene terephthalamide (PPTA) in protective applications has raised significant challenges in degrading and recycling its waste. Conventional disposal methods like landfilling and incineration fail to realize resource recovery and pose environmental risks. This work proposes a green, high-value recycling strategy preserving PPTA’s macroscopic structure. Using waste PPTA fabric as a reinforcement framework and self-made polyarylate (PAR) nanofibers as interfacial functional units, we fabricated a sandwich-like sealed PPTA-f/PAR nanocomposite paper via wet ball milling combined with in situ thermal welding. PAR nanofibers offer high specific surface area and strong interfacial interactions, enhancing sealing and process controllability while suppressing electrical treeing through a dense insulating network. These factors enable synergistic improvements in mechanical strength and breakdown performance. The composite exhibits a breakdown strength of 40 kV/mm (61.2% higher than aramid paper) and a maximum thermal decomposition temperature of 582.2 °C. After 200 °C thermal aging and repeated bending, it retains breakdown strengths of 29.4 kV/mm and 25.2 kV/mm, respectively, showing superior thermal stability and fatigue resistance. Mechanically recyclable after failure, its breakdown strength remains 22.56 kV/mm after three cycles, achieving a favorable balance between performance retention and recyclability.