Polyethylene / Montmorillonite Nanocomposites: Effect of masterbatch composition and maleic anhydride on AC electrical breakdown performance

Two organo-modified montmorillonite (MMT) masterbatch systems (Nanocor C30PE and Nanoblend 2101) were obtained from different manufacturers. The systems were let down by single- screw extrusion into polyethylene blends containing 10 : 90 parts linear : branched material. In the case of the Nanoblend 2101-based system, the linear component was grafted with maleic anhydride. The materials were analysed using XRD and SEM to confirm satisfactory intercalation of the silicate layers throughout the sample. AC ramp breakdown tests were performed on each of the samples and the data fitted to a two- parameter Weibull distribution. The clay had a positive effect on both threshold and shape parameters; in no case was there any reduction in breakdown strength. Dielectric spectroscopy indicated a trebling in the dielectric loss factor for all clay-containing systems.