Effect of radiation dose with low dose rate on degradation of propylene-ethylene copolymer

Medical grade propylene-ethylene (P-E) copolymer was irradiated by gamma rays. The radicals generated in the irradiated P-E copolymer were identified by using electron spin resonance (ESR) technique and the structural changes in the polymer were monitored with Fourier transform infrared spectroscopy (FTIR). The ESR spectra were analysed with computer simulations. The ESR studies show the formation of macro (similar toCH(2)-(C) over dot H-CH2 similar to), peroxy (PO(O) over dot), methyl and acyl (R-(C) over dot=O) radicals and the asymmetric doublet, characteristic of peroxy radicals in the case of the sample irradiated at low dose (1 Mrad) and high doses (30 and 40 Mrad), respectively. The FTIR spectra of irradiated P-E copolymer indicate an increase in the concentration of peroxide groups. The absorption bands of -C=O and -OH groups were increased and the decline in the intensity of -CH3 group absorption band is reported.