Silicon carbide (SiC) high-voltage

high-power semiconductor devices are essential for next-generation power systems

yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under extreme thermal and electrical stresses

highlighting the critical need for novel dielectric materials. This article brings phenyl groups into the side group of conventional silicone elastomers through ring-opening polymerisation and hydrosilylation

developing phenyl-modified silicone elastomers. The material's superior thermal resistance is substantiated through thermal ageing and thermogravimetric analysis. Moreover

this study delineates the insulating robustness of the material by gauging its dielectric breakdown voltage. By subjecting the material to pulse electric fields

we investigate the insulating properties of the encapsulation material under operational conditions reflective of actual service environments. Dielectric testing and molecular electrostatic potential simulations are further employed to analyse the enhancement of the material's insulating properties due to the introduction of phenyl groups. Research studies indicate that phenyl silicone elastomers exhibit outstanding temperature and electrical resistance

performing well under pulsed electric field. This is associated with the phenyl group's rigid structure

conjugated system

and its electron-withdrawing characteristics. Study provides a theoretical foundation for improving the insulating properties of encapsulation materials and the operational reliability of power electronic devices.