Sodium-montmorillonite (Na-MMT) nanoclay was modified with different concentrations of octadecylamine
organic modifying agent at 0.5, 1.0 and 1.5 times the CEC of Na-MMT. Influence of concentration
of modifying agent on properties of the organoclays and natural rubber/organoclay nanocomposites was
investigated. It was found that the optimum concentration of modifying agent was 1.5 times the CEC of
Na-MMT. That is, at this concentration, larger d-spacing of organoclay particles and higher degree of clay
dispersion in natural rubber matrix were observed. Larger interlayer d-spacing also caused enhancement
of the mechanical properties of the NR/organoclay nanocomposites. Additionally, the NR/organoclay
nanocomposites with higher concentration of modifying agent exhibited faster curing reaction with
higher crosslink density. Furthermore, the organoclays with larger d-spacing and higher degree of
dispersion in the natural rubber matrix exhibited enhancement of the mechanical and dynamic properties
and thermal stability of natural rubber/organoclay nanocomposites.