کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1883194 | 1533544 | 2009 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: The mechanism of chitosan degradation by gamma and e-beam irradiation The mechanism of chitosan degradation by gamma and e-beam irradiation](/preview/png/1883194.png)
The mechanism of the radiolytic degradation of chitosan under vacuum and under air is investigated in the dose range 30–300 kGy by EPR spectroscopy coupled with FTIR and gel permeation chromatography (GPC) analysis. A decrease of the number average molecular weights by a factor of 3–4 was monitored in the dose range from 0 to 300 kGy. A deconvolution of the EPR spectra is proposed leading to the identification of intermediate radicals and to a radiolysis mechanism which validity is assessed with respect to free radical and radiation chemistry knowledge of carbohydrate systems. An important result is the EPR identification of stable nitroxyl radicals in the samples irradiated in presence of oxygen. This detection is a proof of the involvement of the amino group in the radiolysis mechanism and prompts the expectation of other related products as hydroxylamine ethers. A practical implication of such observation concerns possible toxicity effects. However, on the base of the low-concentration level of the nitroxyl detected, such risk is considered of negligible importance.
Journal: Radiation Physics and Chemistry - Volume 78, Issues 7–8, July–August 2009, Pages 543–548