Potao Sun,Chaolu Niu,Wenxia Sima,Tao Yuan,Ming Yang,Mingke Zhao,Zheng Fang,QiChang Liu,Qin Deng
Polymer insulation materials are subjected to a combination of electromagnetic fields, mechanical stresses, long-term light exposure, ambient temperature and other operating conditions that produce mechanical and electrical tree damage which lead to insulation failure. Self-healing technology is a fundamental solution to this problem. However, effective long-term self-healing of mechanical and electrical tree damage to insulating materials is extremely challenging. To address this issue, this work reports a magnetic field dual responsive blueberry-like microsphere (MFDR-BLMS) that makes a breakthrough in the long-term self-healing of mechanical and electrical damage. The microspheres are attracted to the vulnerable area of the insulating material by the directional magnetic field. When the damage come into contact with the microspheres, the high thermal conductivity microspheres as a whole rapidly melt and fill the damage channels under the action of electromagnetic induction heating. This method achieves a magnetically dual-action, non-contact, long-term effective self-healing of mechanical and electrical tree damage after photothermal aging of insulation materials. This is expected to eliminate the requirement for human contact during the repair process under live conditions and provides a new technological idea for the industrial application of self-healing materials for electrical insulation.
Self-healing of damage is a common phenomenon in organisms but is hardly ever encountered in rigid polymer materials. For next-generation electricals and electronics, it is crucial to accurately mimic organisms to detect and heal mechanical/electrical damage. Herein, disulfide bond exchange is designed to introduce the self-healing ability in a copolymerized polyimide (copolyimide). A copolyimide insulation film with two diamine monomers is successfully prepared, which also possesses good self-healing ability after being mechanical/electrical damaged. Furthermore, the self-healing copolyimide film still maintains its good Young's modulus (E) >4 GPa, high thermal stability with glass transition temperature (Tg) >190 °C, and excellent insulation property with breakdown strength (Eb) >300 kV mm−1. The combination of the simple copolymerization and unique self-healing ability is suitable for high Tg polyimide to make this an ideal method for insulation field.
High-voltage power transmission in electrical grids requires reliable and durable dielectric polymers for wire insulation 1 , 2 . Electrical treeing caused by high, local electric fields is a damaging process that leads to structure degradation and electrical conduction of dielectric materials, and ultimately, to catastrophic failure of the devices 3 , 4 , 5 . Here, we demonstrate that the addition of less than 0.1 volume per cent of superparamagnetic nanoparticles into a thermoplastic polymer enables the repair of regions damaged by electrical treeing and the restoration of the insulating properties. Under the application of an oscillating magnetic field, the embedded nanoparticles migrate to the electrical trees and generate a higher local temperature, which heals the electrical tree channels in the polymer. Our method allows us to regenerate the dielectric strength and electrical resistivity over multiple cycles of tree formation and healing, which could be used to increase the lifespan and sustainability of power cables for electronics and energy applications.
危险品化学品经营许可证（带存储）