Abstract The influence of curcumin on the thermal stability and degradation kinetics of poly(glycolic acid) (PGA), poly-e-caprolactone (PCL) and their blend has been investigated in detail using thermogravimetric analysis. A 50/50 ratio was chosen for the blend and the effect caused by the addition of different percentages of curcumin (CUR) was evaluated. The thermogravimetric analysis was carried out under an atmosphere of inert nitrogen, operating in a dynamic regime at six different heating rates between 3 and 30 °C/min. The results obtained from the degradation on a blend of PCL and PGA concluded that CUR hardly affects to the decomposition of PCL but instead, it significantly influences the stability of PGA. To observe this effect in detail, a more complete degradation study was carried out for the system formed by PGA incorporating 5% of the drug. The activation energy could be determined accurately using Kissinger and isoconversional methods like KAS and Friedman, without previously assuming a reaction model. Coats-Redfern method and generalized master curves were adopted to determine the optimal mechanism of degradation. Results showed a F1 model as suitable mechanism able to describe the degradation process of PGA with curcumin in a range of conversions between 20 and 60 %. Incorporation of CUR did not change the degradation mechanism of PGA but had a dramatic effect on the activation energy that was significantly lowered.

中文翻译：

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姜黄素对聚（乙醇酸）和聚（ε-己内酯）混合物热降解的影响

摘要 姜黄素对聚乙醇酸 (PGA)、聚己内酯 (PCL) 及其混合物的热稳定性和降解动力学的影响已使用热重分析进行了详细研究。为混合物选择了 50/50 的比例，并评估了添加不同百分比的姜黄素 (CUR) 引起的效果。热重分析是在惰性氮气氛下进行的，在动态状态下以 3 到 30 °C/min 之间的六种不同加热速率运行。从 PCL 和 PGA 混合物的降解中获得的结果得出结论，CUR 几乎不影响 PCL 的分解，而是显着影响 PGA 的稳定性。为了详细观察这种效果，对由 PGA 掺入 5% 药物形成的系统进行了更完整的降解研究。可以使用 Kissinger 和等转化方法（如 KAS 和 Friedman）准确确定活化能，而无需事先假设反应模型。采用 Coats-Redfern 方法和广义主曲线来确定最佳降解机制。结果表明，F1 模型是一种合适的机制，能够描述 PGA 与姜黄素在 20% 和 60% 之间的转化率范围内的降解过程。CUR 的加入并未改变 PGA 的降解机制，但对活化能有显着降低的显着影响。无需事先假设反应模型。采用 Coats-Redfern 方法和广义主曲线来确定最佳降解机制。结果表明，F1 模型是一种合适的机制，能够描述 PGA 与姜黄素在 20% 和 60% 之间的转化率范围内的降解过程。CUR 的加入并未改变 PGA 的降解机制，但对活化能有显着降低的显着影响。无需事先假设反应模型。采用 Coats-Redfern 方法和广义主曲线来确定最佳降解机制。结果表明，F1 模型是一种合适的机制，能够描述 PGA 与姜黄素在 20% 和 60% 之间的转化率范围内的降解过程。CUR 的加入并未改变 PGA 的降解机制，但对活化能有显着降低的显着影响。