Investigation on aging mechanism of polyester under combined stresses

The physical properties of polyester film, such as thermal stability, combined with its mechanical properties, such as tensile break strength, and its electrical strength make it the preferred material for a wide variety of electrical insulation applications. Therefore, polyesters are widely used as insulating material for electric power system equipment such as cables, motors, transformers, and capacitors, since its high dielectric constant and resistance to degradation in high voltage and thermal stresses makes it ideal for mechanical barriers in wire and cable applications. For instance, in transformers and other high-voltage distribution equipment, polyester film is used to wrap the conductors [1]-[3].