Dielectric Relaxation of New Aniline Methyl Methacrylate Copolymer Synthesized by Gamma Irradiation Initiated Polymerization

Abstract

A new copolymer based on gamma radiation initiated polymerization of methyl methacrylate in the presence of aniline was prepared for potential applications in electric fields. The electrical properties of the new material, such as permittivity, relaxation time and ac conductivity, were compared to the properties of poly(methyl methacrylate). The frequency and irradiation dose dependency of the loss tangent factor and dielectric constant showed a Debye dielectric relaxation process. The main objective of the dielectric investigation in this study was to provide a better understanding for the correlated hopping electron process involved in the conduction. On the other hand, for the ac conductivity, at room temperature, there was a deviation in the conduction mechanism of the correlated barrier hopping of electrons between paired and random defects. This deviation showed a maximum value for aniline methyl methacrylate copolymer irradiated at a dose of 30 kGy. The analysis of the data of the dielectric loss showed a well-defined peak at a frequency assigned to dipole relaxations in the system. The results indicated that the gamma irradiation results in the formation of some traps in the energy gap, which reduce the movement of the charge carriers. Also it can be stated that aniline acts as an effective protection agent against structural damage caused by gamma radiation in the copolymer matrix.