کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5203474 | 1381932 | 2008 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Degradation mechanism of poly(lactic-co-glycolic) acid block copolymer cast films in phosphate buffer solution
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آلی
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چکیده انگلیسی
We have investigated the degradation of poly(lactic-co-glycolic) acid copolymer with a lactic to glycolic ratio of 50:50. Solvent-cast films were incubated at 37 °C in phosphate buffered saline solution and their degradation was followed using potentiometry, light microscopy, gravimetry, size exclusion chromatography, differential scanning calorimetry and infrared spectroscopy. The degradation process was found to have two main steps. The first step was observed from 0 to 7 days of degradation. During the first few days a soft layer formed at the surface of the film. As degradation time increased this soft surface layer was found to swell and wrinkle. The polymer molecular weight in the bulk was found to decrease as soon as the film was placed in the medium while the polymer present in the surface layer was found to degrade at a much slower rate. The second step of degradation was found to occur after 8 days. At this stage of the degradation process the molecular weight of the polymer in the bulk of the films was so low that the materials became liquid resulting in the detachment of the film from the glass slide. At this stage the mass loss and amount of acid released in the media were found to increase significantly.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 93, Issue 10, October 2008, Pages 1869-1876
Journal: Polymer Degradation and Stability - Volume 93, Issue 10, October 2008, Pages 1869-1876
نویسندگان
Elisabeth Vey, Caroline Roger, Liz Meehan, Jonathan Booth, Mike Claybourn, Aline F. Miller, Alberto Saiani,