کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10734121 | 1043982 | 2005 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Degradation of chitosan and sodium alginate by gamma radiation, sonochemical and ultraviolet methods
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
تشعشع
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Three degradation methods: ultrasonic, ultraviolet and gamma irradiation were applied to sodium alginate and chitosan in aqueous solutions. The changes in molecular weight were monitored by GPC measurements. It has been found that from the energetic point of view the most effective method for both polymers is gamma radiation method with a yield of scission Gs=0.55Ã10-7mol/J for 1% alginate and Gs=3.53Ã10-7mol/J for 1% chitosan. However, considering the reaction time, the ultraviolet method is the most effective, with reaction rate constant k=0.52h-1 for alginate and 1.6Â hâ1 for chitosan. Based on FTIR spectra, taken before and after degradation it was revealed, that degradation undergoes by the breakage of the glycosidic bonds of polymers. UV spectroscopy showed absorption peak at 265Â nm for alginate, and two peaks at the range of 250-280Â nm for chitosan. UV spectroscopy for ultrasonic is not revealed and any peak suggesting ultrasonic degradation undergoes different mechanism than ultraviolet and gamma degradations, probably mechanical one.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Radiation Physics and Chemistry - Volume 73, Issue 5, August 2005, Pages 287-295
Journal: Radiation Physics and Chemistry - Volume 73, Issue 5, August 2005, Pages 287-295
نویسندگان
Jaroslaw M. Wasikiewicz, Fumio Yoshii, Naotsugu Nagasawa, Radoslaw A. Wach, Hiroshi Mitomo,