The main function of an insulator is to insulate the current carrying
conductors from each other and from the ground, which requires
materials with very low dielectric constant. For rubber, the dielectric
constant increases with temperature due to change in intra and inter
molecular interactions. Therefore it is necessary to modify rubber to
thermally more stable by adding some ingredients or dynamic
vulcanization. The variation of dielectric constants of pure components
and the blends of NR/CS as a function of frequency is shown in
Fig. 5. It shows that the blend NR80CS20 exhibits the lower value; while
the chitosan exhibits the maximum value of dielectric constant. The
dielectric constant values of the blends decreased with increase in
frequency. The effect of blend composition on the dielectric constant
values is given in Table 2 for different frequencies. The table shows
that the dielectric constant of natural rubber is less at higher
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.