Infrared spectra of γ-irradiated poly(acrylic acid)-polyacrylamide complex

Samples of polyacrylamide (PAAm), poly(acrylic acid) (PAA), and their complex were T-irradiated at different doses, namely 48, 96, and 144 KGy. The examination of the infrared spectra of these samples showed that there are no significant observable changes in their spectral features apart from slight changes in the intensities of the absorption bands. The analysis of the absorbances ratios (A 1700 cm(-1)/A 1450 cm(-1)) and (A 1650 cm(-1)/A 1450 cm(-1)), denoted as R-1 and R-2, respectively, showed that these ratios depend on -doses. It was found that in the case of PAA, R-2 assumed linear increase with increasing the dose to 96 KGy and then showed marked decrease. For the complex, R-2 increased slightly by increasing the dose to 96 KGy and then decreased. For PAAm, although irradiation with 48 KGy increases the values of R-2, irradiation with 96 and 144 KGy decreases its value. On the other hand, for the complex, R-2 suggested slight decrease on irradiation with 48 KGy followed by continued increases with increasing the dose up to 144 KGy. The increase in R, and R, may be due to crosslinking as a result of the formation of free radicals. The decrease in these ratios after irradiation with 96 KGy may be due to degradation. It was concluded that gamma-irradiation has a lower effect on the complex (i.e., the complex has a structure which is different from those of PAA and PAAm). (C) 2002 Wiley Periodicals, Inc.