Quantitative and qualitative analysis of segmental dielectricrelaxations and space charge by TSDC in nanocompositesof natural rubber/clay

摘要

The effect of adding three different layered clays, a sodium montmorillonite, and two commercial modified montmorillonites, on the morpho-logy and molecular dynamics of natural rubber characterized by Transmission Electron Microscopy and Thermally Stimulated DepolarizationCurrents (TSDC) was studied. Carbon black was employed as reinforcing filler in a standard compound prepared and used for comparisonpurposes. The morphological results revealed that the sample with Cloisiter15A displays the highest degree of exfoliation, which suggestsstronger compatibility between the organic and inorganic phases. When the dispersion degree increases, a decrease of the activation energywas found from the quantitative analysis of the space charge dielectric relaxations. From the qualitative analysis of the dipolar dielectricrelaxations aroundTg, changes in the dielectric relaxation profile and in the peak localization were attributed to probable interactions betweenthe nanofillers and the elastomer in the glass transition region of the NR.