Influence of critical carbon nanotube loading on mechanical and electrical properties of epoxidized natural rubber nanocomposites

Nanocomposites based on carbon nanotube (CNT) filled epoxidized natural rubber (ENR) were prepared by melt mixing method with the main aim to elucidate the critical CNT loading that provides optimal mechanical and electrical properties. The reinforcing effect of CNT in ENR matrix was assessed from torque difference (MH-ML) and 100% moduli that increased with CNT loading. Furthermore, dielectric constant and electrical conductivity increased with CNT loading. In addition, the percolation threshold concentration was about 2.3 phr of CNT with the t-value of fundamental percolation theory at 1.74. This indicates three dimensional (3D) CNT networks dispersed in the ENR matrix. In addition, the dipole-dipole interactions of ENR and CNT increased the polarization effect that caused formation of conductive material with micro-capacitor characteristics. •The critical CNT loading in ENR composites caused the optimal properties that related to the proposed models.•The interaction between CNT and ENR was described by thermal degradation.•The aspect ratio of CNT in ENR composites was effectively determined by the ESG and Hapin-Tsai models.•CNT network in ENR matrix formed during elongating was related to the resistivity of the composites.•Dielectric constant was related to the conductivity by the critical CNT loading.