Electrospinning Equipment for Research| High-Performance AlzO:/Polyarylate nanocomposite paper with enhancedInsulation, thermal Conductivity, and environmental stability for Advancedelectrical applications

Associate Professor Xiong Siwei from Wuhan Textile University: High-performance Al₂O₃/Polyarylate Nanocomposite Paper with Excellent Insulation, Thermal Conductivity, and Environmental Stability for Advanced Electrical Equipment

With the trend of miniaturization, multifunctional integration, and high-power development in modern electronic devices, insulating materials have become indispensable in electronics, new energy, and safety protection. By isolating conductive components within electronic devices, they provide reliable insulation, ensuring stable operation and extending service life. Aramid paper, currently the most widely used paper-based insulating material, offers excellent mechanical properties and thermal stability. 

However, in the context of rapid advancements in modern electronics, aramid paper faces several challenges:  

1. Insufficient insulation performance: Due to the relatively large diameter of aramid fibers (AF) and weak interfacial interactions, structural defects significantly impair insulation performance under high-voltage conditions.  

2. Poor thermal conductivity: Inadequate heat dissipation leads to localized thermal stress, reducing insulation performance and shortening device lifespan.  

3. Inadequate weather resistance: Aramid paper exhibits weak resistance to UV radiation and high-temperature aging, making it difficult to maintain reliable insulation in harsh environments over extended periods.  

To address these issues, there is an urgent need to develop insulating materials with high electrical insulation, superior thermal conductivity, and strong reliability.  

Fig. 1: Schematic diagram of Al₂O₃/PAR nanocomposite paper preparation. 

Recently, Associate Professor Xiong Siwei from Wuhan Textile University published a study titled "High-Performance Al₂O₃/Polyarylate Nanocomposite Paper with Enhanced Insulation, Thermal Conductivity, and Environmental Stability for Advanced Electrical Applications" in *Chemical Engineering Journal*. The first authors of the paper are Cheng Liang (undergraduate) and Ma Hua (master’s student), with Associate Professor Xiong as the corresponding author.  The research team developed a novel nanocomposite fiber paper (Al₂O₃/PAR nanocomposite paper) using a simple vacuum-assisted self-assembly and thermal treatment method. A dense nanofiber network was constructed from high-aspect-ratio polyarylate (PAR) nanofibers, while alumina nanoparticles (Al₂O₃) provided excellent electrical insulation and thermal conductivity, achieving dual enhancement in both properties.  Additionally, through microstructure modeling and finite element simulations, the study revealed how varying degrees of PAR nanofiber coating on Al₂O₃ nanoparticles influenced insulation performance.

Fig. 2: Electrical insulation performance of Al₂O₃/PAR nanocomposite paper.  

Fig. 3: Finite element simulation of electrical insulation in Al₂O₃/PAR nanocomposite paper.  

The PAR nanofiber network effectively reduced charge injection and matrix erosion, while Al₂O₃ nanoparticles homogenized electric field distribution and suppressed electrical treeing. When Al₂O₃ content was ≤30 wt%, the breakdown strength of the nanocomposite paper increased with higher Al₂O₃ loading, peaking at 115.4 kV/mm (356% of commercial aramid paper) at 30 wt%.  

Scanning electron microscopy (SEM), finite element simulations, and prior studies helped establish the insulation mechanism of Al₂O₃ nanoparticles coated by thermoplastic PAR at different loadings. At low Al₂O₃ content, the nanoparticles were fully encapsulated by the PAR matrix, blocking electrical tree propagation and slowing growth rates, causing current to dissipate along the PAR matrix at the Al₂O₃ interface. With increased loading, slight aggregation formed larger Al₂O₃ clusters, which provided broader current homogenization and dissipation. However, excessive loading led to large, uncoated aggregates, causing electrons to migrate along defects and degrading insulation.  

Fig. 4: Thermal conductivity and thermal management performance of Al₂O₃/PAR nanocomposite paper.  

As Al₂O₃ loading increased within the PAR nanofiber network, the nanoparticles formed a percolation network, establishing efficient heat conduction pathways. This reduced interfacial thermal resistance, enhancing thermal conductivity. Below 40 wt%, thermal conductivity steadily improved, reaching 2.726 W/(m·K) at 30 wt% (2599% of commercial aramid paper).  

In thermal management tests, Al₂O₃/PAR-30 paper exhibited a **4°C higher** surface temperature than aramid paper after 25 s on a 65°C hotplate. When placed on a gradually heating CPU for 60 s, its surface temperature was 11.6°C lower than aramid paper. Even 240 s after CPU shutdown, it remained 3.2°C cooler and maintained excellent heat dissipation over multiple cycles.  

Paper link: [https://doi.org/10.1016/j.cej.2025.162000](https://doi.org/10.1016/j.cej.2025.162000)