In the case of blends the ρv has values in between that of natural
rubber and chitosan. As the concentration of chitosan increases in
the blend the ρv value decreases. The increase in resistivity may be
due to the enhancement in interfacial interaction between the two
phases and reduction in polarity in the blends during vulcanization
and MA treatment. The decrease in resistivity upon heating is
observed. chitosan exhibits high dielectric constant, especially at
lower frequencies. With increase in frequency at first the interfacial
contribution vanishes followed by orientation polarization, which in
turn reduces the dielectric constant at higher frequencies. The
orientation polarization requires more time compared to electronic
and atomic polarization to reach static field value. Therefore, at
lower frequency region, the orientation polarization decreases with
increase in frequency compared to electronic and atomic polarizations.
The interfacial polarization generally occurs at much lower
frequencies. The blend NR85CS15 shows the least frequency
dependent and more stable. Above 20% chitosan in the blend, the
dielectric constant increased, which can be attributed to the change
in overall polarity of the system with the addition of chitosan. The
cross-linked structure will avoid increase in free volume resulting in
stable dielectric properties. The dielectric constant decreases by
vulcanization and it is more stable than pure blend at lower
frequencies. The vulcanized NR90CS10 blend is more stable than MA
compatibilized NR90CS10 and the vulcanized blend is frequency
independent at lower frequencies. The dielectric loss increases with
chitosan content. The magnitude of dielectric loss is minimum for
natural rubber and maximum for chitosan. As the chitosan content
increases, more dipoles are incorporated into the system that leads
to a lag in the orientation of the dipoles upon the application of
electric field. The dielectric loss decreases by the vulcanization and
compatibilization of the blend. The AC conductivity study shows the
vulcanized material sample becomes more insulative compared to
pure and MA treated blends.