235Eco-Friendly Fiber-Reinforced Natural Rubber Green Composites
both the transverse and longitudinal directions (Geethamma et al. 1995). In further
studies, Geethamma et al. (2005) evaluated the dynamic mechanical behavior of
short coir ber–reinforced NR composites. DMA is an effective tool to determine
the dynamic glass transition temperature, T
g
, morphology of crystalline polymers,
and damping (heat dissipation). The dynamic T
g
is dened as the temperature at
which maximum of the tan δ or E″ occurs or middle point of E′ versus temperature
curve or the region where E′ increases with increasing frequency at constant tem-
perature. For a polymer system, values should be the same at a specic frequency.
In this study, the sodium hydroxide-t ...