Thermal, surface, nanomechanical and electrical properties of epoxidized natural rubber (ENR-50)/ polyaniline composite films

•Synthesis of ENR-50/Pani homogenuos composite films.•Percolation threshold is 2.5 w% of Pani.•Hydrogen bonding between ENR-50 and Pani using FT–IR, UV–Visible and DSC.

A new composite material from epoxidized natural rubber (ENR-50) and polyaniline have been successfully prepared. Aniline which was polymerized in the presence of dodecylbenzene sulfonic acid (DBSA), then added to ENR-50 for the preparations of ENR-50/Pani.DBSA composite films. The hydrogen bonding which contribute to the formation of ENR-50/Pani.DBSA composites was observed in FT–IR, UV–Visible and DSC. It showed hydrogen bonding interactions between the epoxy groups in ENR-50 and the amine groups in Pani.DBSA. The morphologies of the prepared materials were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and conductivity measurements revealed that the percolation threshold is at 2.5 w% of Pani.DBSA content. Atomic force microscopy (AFM) micrographs showed that ENR-50 with 5 wt% Pani.DBSA addition has the lowest surface roughness. In addition thermogravimetric analysis indicates improved thermal stability at low Pani.DBSA content. DSC measurements revealed that Tg value increases with increasing Pani.DBSA, indicating that the formation of homogenous composite material. Nanoindentation results show that the hardness (H) and Young's modulus (Es) increased with higher addition of Pani.DBSA polymer.

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