Gamma Irradiation Effect on the Thermal Stability, Optical and Electrical Properties of Acrylic Acid/ Methyl Methacrylate Copolymer Films

摘要

Copolymer films of Acrylic acid/ Methyl methacrylate AAc/MMA with comonomer composition of 60/40 was prepared and then irradiated by gamma irradiation. The effect of irradiation on some of the physical properties of the copolymer films was investigated. The dose level ranged from 5 to 200 kGy. The thermo gravimetric analysis (TGA) showed that the thermal stability of the films increased with irradiation dose up to 100 kGy then it started to decrease. The results of the UV-Visible spectroscopy of the films showed a decrease in the values of optical band gap and band tail width with doses starting from 100 kGy. The DC conductivity (?DC) of the films was found to decrease to about three orders of magnitude from its original value with irradiation dose up to 100 kGy then it started to increase with higher doses. Moreover, the dielectric constant and dielectric loss values were found to increase with dose up to 100 kGy which may be attributed to the increase in the number of dipoles in the films due to the irradiation of the copolymer films in air. The results indicated that crosslinking dominated over chain scission in the copolymer films with irradiation dose up to 100 kGy then at higher doses, chain scission dominated.