High Performance Epoxy Composites Containing Nanofiller Modified by Plasma Bubbles

The thermal conductivity of polymer materials is a fundamental parameter in the field of high-voltage electrical insulation. When the operating frequency and power for electrical equipment or electronic devices increase significantly, the internal heat will increase dramatically, and the accumulation of heat will further lead to insulation failure and serious damage of the whole system. The addition of filler with high thermal conductivity into polymer is a common solution. However, the interfacial thermal resistance between filler and bulk materials is the major obstacle to improve thermal conductivity. Herein, in order to reduce the interfacial thermal resistance, nanofillers are modified by plasma technology. The surface modification of nano-Al2O3 is carried out using plasma bubbles with three atmospheres (Ar, Ar+O2, air) as well as coupling agent. The situation of surface grafting before and after the modification is characterized using FTIR, XPS, and SEM. The effect of the mechanism of modification on the thermal conductivity and reaction pathway is investigated. The results showed that the thermal conductivity after plasma modification is increased significantly. Especially, the thermal conductivity is increased by 35% for the sample modified by Ar+O2 atmosphere. This results because more hydroxyl is introduced on the filler surface by the plasma bubbles, which enhance the interface compatibility between filler and epoxy. In addition, surface insulation performance for the modified samples also is enhanced by 14%. This is associated with the change of surface resistance and trap distribution. These results provide potential support for the development of fabrication for high performance epoxy composites.

Automated summary

The thermal conductivity of polymer materials is crucial for high-voltage electrical insulation. To address the issue of insulation failure and damage caused by increased heat accumulation, the addition of fillers with high thermal conductivity is a common solution. However, the interfacial thermal resistance between filler and bulk materials poses a major obstacle. In this study, nanofillers are modified using plasma technology to reduce interfacial thermal resistance. Results showed significant increase in thermal conductivity after plasma modification, with the sample modified by Ar+O2 atmosphere exhibiting a 35% increase in thermal conductivity. These findings have potential implications for the development of high-performance epoxy composites.