Ethylene vinyl acetate copolymer/halloysite nanotubes nanocomposites with enhanced mechanical and thermal properties

Ethylene vinyl acetate (EVA) nanocomposites filled with halloysite nanotubes (HNTs) were prepared by melt compounding. The homogenous dispersion of HNTs into the EVA matrix was evaluated by SEM and TEM analysis. The addition of HNTs does not influence on the phase separation structure and crystallinity of EVA nanocomposites. Due to the reinforcing effect of HNTs embedded in the EVA elastomer matrix, along with an increase of HNTs concentration, the improvement in tensile properties, by means of modulus at an elongation of 100% and tensile strength, was observed. It was found that tensile strength increased by 27% for EVA nanocomposite with 8 wt% of the HNTs. The values of elongation at break at low HNTs' loading increase and subsequently at higher loading are comparable to the neat EVA copolymer. The elastic deformability and reversibility of the EVA nanocomposites with different HNTs content was analyzed. The cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than for neat EVA copolymer. Furthermore, the limiting oxygen index value for the EVA based nanocomposite with the highest HNTs content (8 wt%) increased from 19.5 to 24.8%. The results show, that thermo-oxidative stability were improved by the incorporation of HNTs into EVA copolymer matrix.