Preliminary study on epoxidized natural rubber latex composites intended for shoe soles applic

Abstract

Epoxidized natural rubber (ENR) is a well-known rubber material exhibits high-damping and better wet-grip compared to normal NR, but its applications are relatively limited and found only in dry rubber sector. This study aims to diversify the application of ENR by introducing it into latex-based products. In this study, ENR latex is prepared via an in-situ epoxidation reactions, followed by ultrafiltration process using membrane separation technology. The prepared ENR latex concentrate exhibits higher mechanical stability time and different viscosity properties compared to commercially available HA latex concentrate. Both ENR latex and HA latex concentrates are compounded via sulphur pre-vulcanisation process and cast into latex films. Although both latexes are compounded at a similar level of vulcanising agents, HA latex films are found to be higher in crosslink density and tensile strength compared to ENR latex films. Addition of nanomaterial slightly increases the crosslink density and tensile strength of both films, but the overall improvement of physical properties was not distinctly discriminative. The presence of nanomaterial also improves the electrical conductivity property of both films. Transmission Electron Microscopy visualized poor distribution of the nanomaterial in the rubber matrix, limiting the reinforcing effect of the nanomaterial, as well as the effectiveness to impart the electrical conductivity. Nevertheless, the study found that the ENR latex concentrate is a suitable material for fabrication of shoe soles, and potentially be used as an alternative material for better wet-grip and damping property.