Influences of carbon nanotubes and graphite hybrid filler on properties of natural rubber nanocomposites

Abstract

Natural rubber (NR) vulcanizates reinforced by carbon nanotubes (CNT, 3 phr), graphite particles (GP) and CNT/GP hybrid filler (varied GP 0–50 phr) were prepared. The stress relaxation behaviors of various filled samples were characterized by the novel temperature scanning stress relaxation (TSSR) technique to elucidate the state and degree of filler dispersion based on initial relaxation modulus, bound rubber, and thermal stability. The incorporation of CNT/GP hybrid filler in NR matrix improved relaxation modulus, bound rubber, and thermal stability of the nanocomposites. The CNT particles in the hybrid composites prevented the re-agglomeration of dispersed GP after mixing by a thermodynamic effect. It was found that a combination of 3 phr CNT and 30 ph GP gave superior properties to NR vulcanizates. That is, good dispersion and distribution of CNT and GP in the NR matrix provided further significant improvements in electrical conductivity and dielectric constant of the nanocomposites. The NR nanocomposites with high conductivity and low dielectric constant seems to be a semi-conductive substrate to be used in many electrical devices.

Keywords

• CNT hybrid graphite
• Natural rubber
• Nanocomposites
• Electrical properties
• Stress relaxation