Physical properties and crystallization behavior of ethylene-vinyl acetate rubber/polyamide/graphene oxide thermoplastic elastomer nanocomposites

Abstract

Graphene oxide (GO) reinforced ethylene-vinyl acetate rubber/ternary polyamide copolymer (EVM/tPA) thermoplastic elastomer (TPE) was prepared via a dynamic vulcanization technique with the assistance of tetraethoxysilane (TEOS) for transesterification crosslinking reaction of EVM. The crosslinked EVM phase was dispersed in continuous tPA phase even at the component ratio of EVM/tPA 70/30 wt%. GO nanosheets were found to be distributed homogeneously in both EVM and tPA phases. The addition of GO up to 1.81 wt% not only enhanced the stress at 100% extension of the TPE, but also increased the dielectric permittivity of the TPE. In particular, the presence of GO nanosheets greatly affected the crystallization behavior of the tPA phase in the EVM/tPA (70/30) TPE that were demonstrated as the increased crystallization temperature, crystallization rate constant and activation energy, as well as a two-dimensional crystal growth mode of tPA. Therefore, the GO acts as a heterogeneous nucleating agent for tPA with nucleation activity α of 0.4–0.6, as well as reinforcement for the EVM/tPA TPE.