Optimisation method for carbon black distribution of polypropylene‐based semi‐conductive screen materials and its effect on charge emission behaviour at screen/insulation interface

Abstract

AbstractThe semi‐conductive (SC) screen materials used in polypropylene (PP)‐based cables are usually multi‐component composites. Polypropylene shows poor compatibility with carbon black (CB), and CB particles tend to disperse in the elastomer phase, which results in CB non‐uniform dispersion in screen materials. The non‐uniform distribution of CB will cause abnormal electric fields at the screen/insulation interface and affect insulation performance. This paper prepared modified PP grafted by molecule maleic anhydride, and four PP‐based SC shielding materials were blended in combination with PP, PP‐g‐MAH, and thermoplastic elastomer (POE) as matrix resin. The CB distribution, electrical conductivity, and basic physical properties of the shielding material were characterised. Different screen materials were served as electrodes to test their effects on the space charge and conductivity characteristics of insulation. The relationship between the macroscopic properties and the distribution characteristics of CB was discussed. Results show that the selective dispersion of CB in screen material was improved by PP‐g‐MAH and the surface electric potential distribution was homogenised. Charge emission at the screen/insulation interface and conductivity can be reduced by homogenising the CB distribution. CB/PP‐g‐MAH/POE prepared in this paper exhibits relatively uniform CB distribution, which can reduce the charge emission from the screen/insulation interface.