Dubey Satya P, Abhyankar Hrushikesh A, Marchante Veronica, Brighton James L, Blackburn Kim, Temple Clive, Bergmann Björn, Trinh Giang, David Chantal
Advanced Vehicle Engineering Centre (AVEC), School of Aerospace, Transport and Manufacturing (SATM), Cranfield University, MK43 0AL Cranfield, UK.
Polymer Engineering, Fraunhofer.-ICT, Joseph-von-Fraunhofer-Straße 7, 76327 Pfinztal, Germany.
Polymers (Basel). 2016 Apr 22;8(4):164. doi: 10.3390/polym8040164.
PLA is one of the most promising bio-compostable and bio-degradable thermoplastic polymers made from renewable sources. PLA is generally produced by ring opening polymerization (ROP) of lactide using the metallic/bimetallic catalyst (Sn, Zn, and Al) or other organic catalysts in a suitable solvent. In this work, reactive extrusion experiments using stannous octoate Sn(Oct)₂ and tri-phenyl phosphine (PPh)₃ were considered to perform ROP of lactide. Ultrasound energy source was used for activating and/or boosting the polymerization as an alternative energy (AE) source. Ludovic software, designed for simulation of the extrusion process, had to be modified in order to simulate the reactive extrusion of lactide and for the application of an AE source in an extruder. A mathematical model for the ROP of lactide reaction was developed to estimate the kinetics of the polymerization process. The isothermal curves generated through this model were then used by Ludovic software to simulate the "reactive" extrusion process of ROP of lactide. Results from the experiments and simulations were compared to validate the simulation methodology. It was observed that the application of an AE source boosts the polymerization of lactide monomers. However, it was also observed that the predicted residence time was shorter than the experimental one. There is potentially a case for reducing the residence time distribution (RTD) in Ludovic due to the 'liquid' monomer flow in the extruder. Although this change in parameters resulted in validation of the simulation, it was concluded that further research is needed to validate this assumption.
聚乳酸（PLA）是最有前景的可生物堆肥和可生物降解的热塑性聚合物之一，由可再生资源制成。聚乳酸通常是通过在合适的溶剂中使用金属/双金属催化剂（锡、锌和铝）或其他有机催化剂对丙交酯进行开环聚合（ROP）来生产的。在这项工作中，考虑使用辛酸亚锡Sn(Oct)₂和三苯基膦（PPh）₃进行反应挤出实验，以实现丙交酯的开环聚合。超声能源被用作替代能源（AE）来激活和/或促进聚合反应。为模拟挤出过程而设计的Ludovic软件必须进行修改，以便模拟丙交酯 的反应挤出以及在挤出机中应用替代能源。建立了丙交酯反应开环聚合的数学模型，以估计聚合过程的动力学。然后，Ludovic软件使用通过该模型生成的等温曲线来模拟丙交酯开环聚合的“反应性”挤出过程。将实验结果和模拟结果进行比较，以验证模拟方法。观察到替代能源的应用促进了丙交酯单体的聚合。然而，还观察到预测的停留时间比实验停留时间短。由于挤出机中“液体”单体的流动，在Ludovic中可能存在减少停留时间分布（RTD）的情况。尽管参数的这种变化导致了模拟的验证，但得出的结论是，需要进一步研究来验证这一假设。
