Research on electrical properties of flame retardant polyolefin materials for UHV optical cable

Low-smoke halogen-free materials are commonly used in ultra high voltage cables. During the extrusion process, the crystallinity was affected by additives and processing conditions, thus affecting the electrical properties of sheathing. In order to study the electrical properties of the cable sheath materials, samples were prepared with different color masterbatch, addition ratio and processing conditions. The crystallization characteristics, resistivity and space charge characteristics were studied. The results show that the higher the addition ratio of masterbatch, the lower the crystallinity and the lower the volume resistivity. The parameters that affect the crystallinity of in the molding process will affect the electrical properties of flame retardant polyolefin, but the post-treatment can eliminate this effect. The decrease of crystallinity leads to the increase of internal defects in medium, which limits the charge migration, resulting in the decrease of overall carrier mobility and the increase of space charge aggregation in the sample.