Synthesis of PLGA using a C ₃-symmetric Zr (IV) amine tris(phenolate) alkoxide initiator and the effects of gamma radiation on its properties

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• 作者：Fernando dos Santos Peleias Junior ; Matthew David Jones…
• 关键词：PLGA ; Synthesis ; Zirconium ; Gamma irradiation ; Degradation
• 刊名：Polymer Bulletin
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：74
• 期：1
• 页码：91-105
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Polymer Sciences; Soft and Granular Matter, Complex Fluids and Microfluidics; Characterization and Evaluation of Materials; Physical Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：1436-2449
• 卷排序：74

文摘

In this paper, we report the preparation and characterisation of poly(lactic-co-glycolic) acid (PLGA) using a C₃-symmetric Zr (IV) amine tris(phenolate) alkoxide initiator. Although the zirconium alkoxide initiator is slower than the most commonly used Sn(Oct)₂, relatively high molecular weights were obtained at a temperature of 130 °C, for a monomer to initiator ratio of 1000/1 (24 h) and 5000/1 (48 h). The degree of racemisation also depends on the initiator used. The reactions performed with the zirconium initiator showed a higher degree of racemisation when compared to those performed with Sn(Oct)₂. A slight increase in the racemisation with time was also observed. The effects of gamma radiation on PLGA were also studied. Doses commonly applied to sterilise materials for biomedical applications were employed—10, 18, 25 and 50 kGy. The molecular weight of all samples irradiated decreased in a dose-dependent fashion—up to 56 % loss for 10 kGy and 72 % for 50 kGy—but were less pronounced for higher doses. Changes in thermal properties, such as melting point, glass transition temperature and enthalpy of crystallisation and fusion, were also observed after irradiation.