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引用次数: 0
摘要
在超临界二氧化碳介质中演示了聚乳酸(PLA)的化学解聚。反应中未使用催化剂、有机溶剂或水。聚乳酸开环聚合反应中使用的主要原料--内酯异构体以高产率被生产出来。更具体地说,在 200 °C 和 310 巴条件下,120 分钟内生产出的内酯是唯一的非气态产物,产量为初始聚合物质量的 93%。研究了反应温度、时间和压力对聚乳酸解聚产物的影响。虽然内酯产量和分布受反应温度和时间的影响很大,但随着压力的增加,产量和分布得到了进一步改善。研究结果表明,超临界 CO2 可作为聚乳酸降解的理想反应介质,提供高产率的原料生产。该工艺可实现聚乳酸的绿色解聚,并通过闭环生产促进其循环经济。
High-yield production of lactide isomers from depolymerization of polylactic acid in supercritical carbon dioxide
Chemical depolymerization of polylactic acid (PLA) was demonstrated in supercritical carbon dioxide medium. No catalyst, organic solvent or water was employed in the reaction. The primary feedstocks used in ring opening polymerization of PLA, lactide isomers, were produced with high yield. More specifically, lactides were produced as the sole nongaseous products with a 93 % yield based on the initial polymer mass at 200 °C and 310 bar in 120 min. The influences of the reaction temperature, time, and pressure on PLA depolymerization products were investigated. While the lactide yield and distribution were highly influenced by the reaction temperature and time, further improvement was attained with an increase in the pressure. The results demonstrate that supercritical CO2 can be applied as a promising reaction medium for PLA degradation, providing a high-yield production of its feedstock. The process can enable green depolymerization of polylactic acid and promote its circular economy with a closed loop production.
期刊介绍:
The Journal of Supercritical Fluids is an international journal devoted to the fundamental and applied aspects of supercritical fluids and processes. Its aim is to provide a focused platform for academic and industrial researchers to report their findings and to have ready access to the advances in this rapidly growing field. Its coverage is multidisciplinary and includes both basic and applied topics.
Thermodynamics and phase equilibria, reaction kinetics and rate processes, thermal and transport properties, and all topics related to processing such as separations (extraction, fractionation, purification, chromatography) nucleation and impregnation are within the scope. Accounts of specific engineering applications such as those encountered in food, fuel, natural products, minerals, pharmaceuticals and polymer industries are included. Topics related to high pressure equipment design, analytical techniques, sensors, and process control methodologies are also within the scope of the journal.