Effect of Modified Natural Rubber and Functionalization of Carbon Nanotubes on Properties of Natural Rubber Composites

The intention of this work was to prepare natural rubber filled with carbon nanotubes (CNT). Various types of natural rubber, including unmodified natural rubber and epoxidized natural rubber with 25 mol% epoxy groups (i.e., ENR-25) were exploited. The state of CNT dispersion in the unmodified natural rubber matrix was improved by the modification of CNT surface with silane coupling agent (Si-69). The modification was carried out by in-situ method, i.e., the silane was directly added during the preparation process of the composites in the internal mixer. The interaction between CNT surface and rubber molecules, with and without silane modification, was characterized by ATR-FTIR. measurements. The mechanical properties and crosslink densities were investigated, the electrical conductivity was characterized to determine the percolation threshold.