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.