Influence of different vulcanizing agents on structures and properties of sepiolite-filled natural rubber composites

Abstract

This study aimed to explore the best cross-link agent for preparing natural rubber (NR) composites containing sepiolite as filler. Three types of vulcanizing agents, namely, sulfur, peroxide, and phenolic resin, were employed, and their effects on the thermomechanical and mechanical properties and microstructures were investigated. Compared to other vulcanizing agents, the greatest thermomechanical and mechanical properties improvement was achieved by using phenolic resin as a crosslinker. The highest tensile stress and tensile strength improvement were also achieved from the phenolic resin system. Tensile strength was improved by approximately 78%, nearly twice as much as that in the sulfur system. Such drastic improvement was attributed to the combined effect of homogeneity dispersion and strong adhesion between rubber and filler, as revealed by Fourier-transform infrared spectroscopy, facilitating the strain-induced crystallization process in NR. The phenolic resin was the best vulcanizing agent for preparing NR/sepiolite composites.

Keywords

• polymer composites
• rubber
• vulcanizing agents
• sepiolite filler