کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5204876 1381974 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effects of residual metal compounds and chain-end structure on thermal degradation of poly(3-hydroxybutyric acid)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Effects of residual metal compounds and chain-end structure on thermal degradation of poly(3-hydroxybutyric acid)
چکیده انگلیسی

Thermal degradation behaviours of poly(3-hydroxybutyric acid) (P(3HB); bacterial poly[(R)-3-hydroxybutyric acid] and synthetic poly[(R,S)-3-hydroxybutyric acid] samples, were examined under both isothermal and non-isothermal conditions. The inverse of number-average degree of polymerisation for all P(3HB) samples decreased linearly with degradation time during the initial stage of isothermal degradation at a temperature ranging from 170-190 °C. In addition, crotonyl unit was detected in the residual polymer samples as main ω-chain-end. These results indicate that the dominant thermal degradation reaction for P(3HB) is a random chain scission via cis-elimination reaction of P(3HB) molecules. It was found that the presence of either Ca or Mg ions enhances the depolymerisation of P(3HB) molecules, while that Zn ions hardly catalyse the reaction. As a result, a shift of thermogravimetric curves toward the lower temperature regions was observed for the P(3HB) samples containing high amounts of Ca and Mg compounds.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer Degradation and Stability - Volume 91, Issue 4, April 2006, Pages 769-777
نویسندگان
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