Poly(L-lactide). XI. Lactide formation by thermal depolymerisation of poly(L-lactide) in a closed system
Poly(L-lactide). XI. Lactide formation by thermal depolymerisation of poly(L-lactide) in a closed system
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DOI：
10.1016/s0141-3910(03)00150-2
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发表时间：
2003
影响因子：
5.9
通讯作者：
H. Tsuji;I. Fukui;H. Daimon;K. Fujie
中科院分区：
文献类型：
--
作者：
H. Tsuji;I. Fukui;H. Daimon;K. Fujie
聚（1-丙交酯）的热降解（解聚）[即，聚（1-乳酸）（PLLA）]的解聚在密封管中作为封闭系统在250-290 °C的温度范围内进行15小时，而不进一步添加解聚催化剂，并且使用X射线衍射法、凝胶渗透色谱法（GPC）和气相色谱法（GC）监测通过PLLA的解聚形成丙交酯。当在270和250 °C下进行热降解10 h时，丙交酯和l-丙交酯的最高产率分别低至14%和8%。L-丙交酯、d-丙交酯和内消旋丙交酯的组分分别随降解温度和时间的增加而减少和增加。在这项研究中的低产量的丙交酯可以解释由所形成的丙交酯的聚合和通过形成低分子量的化合物而不是丙交酯，而低产量的L-丙交酯是由于形成大量的内消旋和d-丙交酯，除了低产量的丙交酯。讨论了D-和内消旋丙交酯形成的可能途径。
Thermal degradation (depolymerisation) of poly(l-lactide) [i.e., poly(l-lactic acid) (PLLA)] was carried out in a sealed tube as a closed system in the temperature range of 250–290 °C for 15 h without further addition of depolymerisation catalyst, and lactide formation by depolymerisation of PLLA was monitored using X-ray diffractometry, gel permeation chromatography (GPC), and gas chromatography (GC). The highest yields of lactides and l-lactide were as low as 14 and 8%, when thermal degradation was performed for 10 h at 270 and 250 °C, respectively. The fractions of l-lactide and of d- and meso-lactides respectively decreased and increased with increasing degradation temperature and time. The low yield of lactides in this study can be explained by polymerization of the formed lactide and by formation of low molecular weight compounds other than lactides, while the low yield of l-lactide is attributable to the formation of high amounts of meso- and d-lactides, in addition to the low yield of lactides. The probable pathways for the formation of D- and meso-lactides are discussed.