Structure property relationships in polyethylene/montmorillonite nanodielectrics

The influence of a montmorillonite (MMT) nanoclay, functionalized with dimethyl-di(hydrogenated tallow) quaternary amine, on structural evolution and electrical characteristics of a designed polyethylene system has been studied. Samples were prepared by mixing a polyethylene/MMT masterbatch into a matrix system containing 10% high density polyethylene and 90% low density polyethylene using an extruder; X-ray diffraction results suggest good dispersion and exfoliation, as no basal peak was observed. The introduction of this MMT system was found to result in little disruption of the polymer crystallization process and analysis of the crystallization kinetics of the matrix polymer suggests that it interacts only weakly with the incorporated MMT. This is in sharp contrast to our previous studies of a differently functionalized MMT system. Electrically, this combination of highly dispersed MMT within a weakly interacting polymer matrix results in a significant enhancement in short-term breakdown strength. However, this is accompanied by a massive increase in dielectric loss.