Nanofiber Production Equipment| Professor Xiong Siwei from Wuhan Textile University in CEJ: High-Performance Polyarylate Nanofiber Membrane with Ultra-Thin Structure, Multi-Environmental Tolerance and Recyclability for Advanced Electrical Insulation

Wuhan Textile University Associate Professor Xiong Siwei's CEJ Publication: High-Performance Polyarylate Nanofiber Membranes with Ultra-Thin Structure, Multi-Environmental Tolerance, and Recyclability for Advanced Electrical Insulation

With the continuous innovation and advancement of electrical equipment and power system technologies, insulating materials play a crucial role in ensuring the safe, stable, and efficient operation of equipment. Polymer-based insulating paper is widely used in electrical devices due to its lightweight, high strength, excellent flexibility, and ease of processing. Aramid insulating paper, as a high-performance insulating material, exhibits superior mechanical properties, high-temperature resistance, and chemical stability compared to traditional insulating paper.However, with the increasing demands for higher integration, lightweight, and miniaturization in electrical equipment, traditional submillimeter-thick aramid insulating paper faces limitations in balancing space utilization and insulation performance, restricting its application in high-performance electrical devices. Aramid nanofiber insulating paper has broad applications in the insulation field due to its high specific surface area and large aspect ratio. Nevertheless, the inherent molecular chain structure of aramid nanofibers limits further enhancement of insulation performance. Additionally, challenges such as lengthy preparation processes and high manufacturing difficulty hinder the large-scale application of aramid nanofiber insulating paper.Therefore, developing thin polymer fiber-based insulating paper with excellent insulation properties is essential for the further advancement of modern electrical equipment.

Figure 1: Schematic of PAR nanofiber membrane preparation

Recently, Associate Professor Xiong Siwei from Wuhan Textile University published his latest research, "High-performance polyarylate nanofiber membranes with ultra-thin structure, multi-environmental tolerance, and recyclability for advanced electrical insulation," in Chemical Engineering Journal. The first author of the paper is Ma Hua, a master's student at Wuhan Textile University, and the corresponding author is Associate Professor Xiong Siwei. This work successfully prepared a 30 μm-thick PAR nanofiber membrane using a melt-spinning and in-situ splitting strategy combined with scalable thermal pressing. The high-aspect-ratio PAR nanofibers formed a dense 3D network structure under thermal pressing, creating intricate charge dissipation paths. Compared to commercial aramid paper, the PAR nanofiber membrane exhibited superior insulation performance and maintained stability in extreme environments, fully meeting the demands of highly integrated electrical equipment under harsh conditions. Moreover, the thermoplastic nature of PAR nanofibers enables closed-loop recycling.

Figure 2: Microstructure of PAR nanofiber membrane

As the thermal pressing temperature increased, the PAR nanofiber membrane surface became smoother with almost no visible pores. In contrast, commercial aramid paper retained distinct fiber structures with weak interfacial bonding and large pore defects. This is attributed to the excellent thermoplasticity of PAR nanofibers, where locally melted molecular chains during thermal pressing enhanced interfacial bonding, reduced defects, and improved structural integrity.

Figure 3: Electrical insulation performance of PAR nanofiber membrane

The breakdown strength of the PAR nanofiber membrane initially increased and then decreased with rising thermal pressing temperature. At 170°C, the breakdown strength reached 52.12 kV/mm. When further increased to 210°C, it peaked at 71.46 kV/mm—252.4% higher than commercial aramid paper—due to enhanced interfacial bonding and reduced internal voids. The dense 3D network structure also suppressed charge aggregation and prolonged charge migration paths, delaying electrical tree growth.

Figure 4: Thermal stability, flexibility, and lightweight properties of PAR nanofiber membrane

At elevated temperatures, commercial aramid paper showed significant shrinkage and darkening due to oxidation, indicating structural degradation. In contrast, the PAR nanofiber membrane maintained superior dimensional stability with minimal thermal deformation. Its tensile strength reached 86.57 MPa, a 21.4% improvement over commercial aramid paper. Notably, the PAR nanofiber membrane also demonstrated outstanding lightweight properties and stability. Its thermoplastic recyclability enables efficient resource reuse, offering a sustainable pathway for high-performance insulating materials.

Paper link: https://doi.org/10.1016/j.cej.2025.164782