Octadecylammonium montmorillonite/natural rubber/cis-1,4-polybutadiene nanocomposites

Octadecylammonium montmorillonite/natural rubber/cis-1,4-polybutadiene (OMMT/NR/BR) nanocomposites were prepared by direct mechanical blending. The structure of these nanocomposites and the dispersion state of OMMT particles were evaluated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The cure characteristics, static mechanical properties, dynamic mechanical properties, and thermal stability were also determined. TEM confirmed that the majority of the OMMT particles was dispersed uniformly in the NR matrix. The XRD patterns revealed that the clay mineral particles were completely exfoliated when the OMMT content was < 6 mass%. The addition of OMMT decreased the scorch time (Ts) of the NR/BR blends and led to synchronic vulcanization of NR and BR. Nanocomposites containing 6 mass% OMMT showed a tensile strength of 19.6 MPa, an increase by 90.3% compared to the pure NR/BR hybrids. Dynamic mechanical analysis indicated that the peak loss factor (tan δ) was lower than that of NR/BR and shifted to higher temperatures, especially for the NR phase. OMMT/NR/BR nanocomposites had exactly the same onset decomposition temperature and lower thermal degradation rate as the NR/BR blends.