The study of gamma irradiation effects on poly (glycolic acid) |
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| Authors: | Rajeswara Rao Nakka Venkatappa Rao Thumu Ramana Reddy SVS Sanjeeva Rao Buddhiraju |
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| Institution: | 1. Department of Physics, National Institute of Technology, Warangal-506004, Indiarajeshn9@gmail.com;3. Department of Physics, National Institute of Technology, Warangal-506004, India;4. Department of Physics, Government Degree College, Mulugu, Warangal, India |
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| Abstract: | We have investigated the effects of gamma irradiation on chemical structure, thermal and morphological properties of biodegradable semi-crystalline poly (glycolic acid) (PGA). PGA samples were subjected to irradiation treatment using a 60Co gamma source with a delivered dose of 30, 60 and 90?kGy, respectively. Gamma irradiation induces cleavage of PGA main chains forming ～O?H2 and ?H2COO～ radicals in both amorphous and crystalline regions. The free radicals formed in the amorphous region abstract atmospheric oxygen and convert them to peroxy radicals. The peroxy radical causes chain scission at the crystal interface through hydrogen abstraction from methylene groups forming the ～?HCOO～ (I) radical. Consequently, the observed electron spin resonance (ESR) doublet of irradiated PGA is assigned to (I). The disappearance of the ESR signal above 190°C indicates that free radicals are formed in the amorphous region and decay below the melting temperature of PGA. Fourier transform infrared and optical absorption studies confirm that the  | |
| Keywords: | gamma irradiation poly (glycolic acid) peroxy radicals degree of crystallinity micro-cracks |
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