Synthesis and purification of poly(L-lactic acid) using a one step benign process
Synthesis and purification of poly(L-lactic acid) using a one step benign process
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采用一步良性工艺合成和纯化聚（L-乳酸）
DOI：
10.1039/c2gc35074b
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发表时间：
2012
期刊：
影响因子：
9.8
通讯作者：
F. Dehghani
中科院分区：
文献类型：
--
作者：
Sherry Y. Lee;P. Valtchev;F. Dehghani
本研究以超临界二氧化碳(SCCO_2)为溶剂，控制相对分子质量，合成并纯化了聚L-乳酸(PLLA)。低分子量聚乳酸的合成在药物输送、可吸收植入物和可注射聚合物的共聚等方面具有重要的应用价值。聚合反应分别以2-乙基己酸锡(锡(OCT)2)和二甘醇(DEG)为催化剂和引发剂。用凝胶渗透色谱仪、核磁共振氢谱、红外光谱、热重分析和差示扫描量热法对产物进行了表征和分析。重点考察了反应温度、反应时间和压力对聚合物数均相对分子质量、产率和多分散指数的影响。统计分析表明，温度对锰、产率和PDI的影响最大，其次是时间，然后是压力。由于反应物在CO2中的溶解度增加，温度的升高导致了锰产率和PDI的显著增加。时间和压力对Mn和产量有较大影响，但对PDI影响不大。合成低相对分子质量聚乳酸的最佳工艺条件为：温度80℃，反应时间17h，反应时间160bar。类似的条件也进行了测试，发现对去除杂质是有效的。研究结果表明，采用一锅法合成和纯化聚乳酸是可行的。在所研究的范围内，我们获得了高产率、很低的pDI值和可调的Mn范围(1200~13 700g−1)。该工艺消除了有毒有机溶剂、稳定剂和酯化促进剂的使用。低分子量聚乳酸的合成在药物输送、可吸收植入物和可注射聚合物的共聚等方面具有重要的应用价值。
In this study, supercritical carbon dioxide (scCO2) was used as an alternative solvent for the synthesis and purification of poly(L-lactic acid) (PLLA) with a control on molecular weight. The synthesis of low molecular weight PLLA is desirable for applications such as drug delivery, resorbable implant applications and copolymerization of injectable polymer. Polymerizations were carried out in the presence of tin(II) 2-ethylhexanoate (Sn(Oct)2) and diethylene glycol (DEG) as catalyst and initiator, respectively. The resultant polymers were characterized and analysed by GPC, 1H NMR, ATR-FTIR, TGA and DSC. In particular, the effects of temperature, reaction time and pressure on polymer number average molecular weight (Mn), yield and polydispersity index (PDI) were investigated. Statistical analysis showed that temperature had the most significant effect on Mn, yield and PDI; this was followed by time and then pressure. An increase in temperature led to a significant increase in Mn, yield and PDI due to enhanced reactants solubility in CO2. Time and pressure had considerable effect on Mn and yield but not PDI. The optimum conditions for synthesising low molecular weight PLLA was 80 °C, 160 bar and 17 hours. Similar conditions were also tested and found to be efficient for removing the impurities. The results of this study demonstrated the feasibility of using a one pot process for the synthesis and purification of PLLA. We achieved high yield, very low PDI and tuneable Mn ranging from 1200 to 13 700 g mol−1 within the range examined. The process allowed eliminating the use of toxic organic solvent, stabilizer and esterification promoting agent. The synthesis of low molecular weight PLLA is desirable for applications such as drug delivery, resorbable implant applications and copolymerization of injectable polymer.
影响因子：
16.6
作者：
Jacobson, Gunilla B.;Shinde, Rajesh;Zare, Richard N.
通讯作者：
Zare, Richard N.