wherehis the slope of the initial portion of the plot of Qt
vs.t
1/2
andQ1is the equilibrium mole percentage uptake.
Fig. 8demonstrates the change in diffusion coefficient of
benzene as a function of weight percentage of filler. The
diffusion coefficient decreases dramatically upon the addition of filler. The XSBR system exhibits lower diffusivity
value that indicates higher polymer/filler interaction. It is
also due to the restricted chain mobility of XSBR because
of its high cohesive energy density. The NR chain segments
are more flexible and it exhibits higher diffusivity values as
compared to XSBR. But for 70/30 NR/XSBR blend system the diffusivity first decreases upon the addition of filler
while it shows remarkable increase at higher loading. The