Fig. 10 shows relaxation spectra calculated from Eq.
(2), for the NR/clay nanocomposites. The peaks of the
relaxation spectrum were in the temperature range 40–
100 C. For unfilled NR, a broad shallow peak is observed
in this temperature range: this is attributed to the
relaxation of the naturally occurring network, generated
by the end groups of the NR molecules [31]. Addition of
Na-MMT did not affect the shallow peak below 100 C.
Fig. 10 shows taller peaks observed for the NR/HEX-16C
and NR/OC-18C nanocomposites, in the temperature
range 40 to 70 C.