Journals Proceedings

Abstract

The backbone of Natural rubber (NR), polyisoprene, is derived from the polyacetylene backbone through the saturation of every other double bond. Polyisoprene is a potential candidate for materials used in various devices: solar cells, LEDs, and FETs. It is also used in electrically energized line services as electrical energy utilities without any energy breakdown. Therefore, analysis of dielectric property becomes inevitable since they determine the end electrical applications, per se, insulation. Present work is aimed at the determination of dielectric constant of natural rubber by using the method proposed by Robert and Von- Hippel. The effect of microwave frequency, namely 9.6 GHz and 26 GHz, as well as chemical modification brought about by vulcanization and reinforcement on dielectric constant values was probed. Impedance spectroscopy can be used to monitor the progress of reactions in polymer forming systems for insitu real time process control. Dielectric constant and dielectric loss have also been evaluated to substantiate the insulating nature of cured and uncured polyisoprene over a range of temperature and frequency using impedance analyzer in the frequency region 50 Hz to 5 MHz. Density functional Coloumb attenuating method CAM-B3LYP/6-311++G(d,p) and Hartree- Fock HF/6-311++G(d,p) calculations were performed to obtain the total static dipole moment (μtot), polarizability (α), first hyperpolarizability (β0) and natural bonding orbital (NBO) analysis of this isoprene molecule. The NBO calculation was performed using the NBO program as implemented in GAUSSIAN 09W package in order to understand the magnitude of atomic charges in the molecule. The present investigation intends to look into accurate electrical properties of natural rubber composites for practical uses as electrically insulating material and also to help one better understand electrical conduction mechanisms which eventually leads the material to dielectric breakdown.