On the structural analysis of γ -ray induced primary free radicals in UHMWPE and Vitamin e stabilized UHMWPE by ESR spectroscopy

Authors

Malik Sajjad Mehmood, University of Engineering and Technology Taxila
Muhammad Shah Jahan, University of MemphisFollow
Tariq Yasin, Pakistan Institute of Engineering and Applied SciencesFollow
Muhammad Tariq, University of Engineering and Technology Taxila
Mohammad Ahmad Choudhry, University of Engineering and Technology Taxila
Masroor Ikram, Pakistan Institute of Engineering and Applied SciencesFollow

Abstract

Oriented allyl radicals are detected at room temperature in gamma irradiated UHMWPE. The effects of vitamin E and storage at room temperature on this oriented structure are also investigated during the study. While testing powder as well as compression-molded solids, with or without vitamin E, a typical ESR spectrum was recorded at room temperature following 100 kGy gamma dose and subsequent storage at -78.5°C for one year. The simulated results show that the relative abundance of 5% alkyl, 68% allyl, and 27% polyenyl produced a 98.7% best fit of experimental ones. Furthermore, the allyl radical signal gives approximately 20% of random orientations and 80% of oriented molecules. In oriented PE, measured at -196°C, Ohnishi et al. (1916) observed 25 lines within a total magnetic field width of approximately 133 G. Our spectra also show 25 lines spread over 136 G in UHMWPE powder samples and at room temperature after one year of storage.

Publication Title

Journal of Spectroscopy

Recommended Citation

Mehmood, M., Jahan, M., Yasin, T., Tariq, M., Choudhry, M., & Ikram, M. (2015). On the structural analysis of γ -ray induced primary free radicals in UHMWPE and Vitamin e stabilized UHMWPE by ESR spectroscopy. Journal of Spectroscopy, 2015 https://doi.org/10.1155/2015/653853