具有拓扑结构的离子液体齐聚物对聚乳酸/可生物降解聚酯界面诱导与调控机理的研究

The blends, poly(lactic acid) (PLA) and biodegradable polyester (Bio-polyester), as a completely biodegradable material with excellent performance, plays the role of guide for future development. However the difference of segment configuration and conformation between both components leads to the existence of weak-bonding force on the phase interface, affecting the final performance of the material to a large extent. The research involved interfacial inducing and controlling agent, such as block copolymer and phase interface cross-linking agents, mainly focuses on their impact on the performance, yet the mechanism about interfacial inducing and controlling should to be confirmed further. In this project, based on the luminescent properties of rare-earth element, a series of novel ionic liquid oligomers containing rare-earth element with topological structure (TOILs) for interfacial inducing and controlling agent should be designed and synthesized. And then, combining other methods, the effects of TOILs with various structures, i.e., topology configuration, structure of branched chains and the ionic cluster construction, on the interfacial inducing and controlling of PLA/Bio-polyester blends should be investigated via detecting luminescent properties of TOILs in PLA/Bio-polyester blends during the processes of heating and melt cooling, so the effects of TOILs on the interfacial bonding strength and stability of PLA/Bio-polyester blends were also studied. In addition, the regularities of transmission and dissipation of outside energy across the interfaces of blends should be investigated, so the development and evolution of the matrix structures, dispersion phase and the interface morphology under the external effects were also investigated. And then, the mechanism of interfacial inducing and controlling of PLA/Bio-polyester blends containing TOILs should be revealed. For further, a new theory models of interfacial inducing and controlling for polymer blends should be provided.

聚乳酸(PLA)与可生物降解聚酯(Bio-polyester)共混时，需应用相容剂对共混物进行增容和界面调控，而有关其界面调控机理的探讨需深入与明确。本项目借助稀土元素的发光特性，拟合成含稀土的拓扑结构离子液体齐聚物(TOILs)，通过TOILs在PLA/Bio-polyester共混物相界面的发光示踪，结合其它测试与表征方法，研究TOILs的拓扑结构、支链结构及离子团簇结构对PLA/Bio-polyester在受热熔融及熔体冷却过程中界面构筑及本体相凝聚态结构形成的作用，并考察其对共混物界面粘结强度及稳定性的影响。此外，认识外场能量在调控后的相界面中的传输及耗散规律，以及外场作用下共混物本体相、分散相及界面形态结构的发展演化过程，揭示TOILs对PLA/Bio-polyester共混物相界面调控的机理，并在此基础上发展新的聚合物界面调控理论。

聚乳酸（PLA）/可生物降解聚酯的共混改性因不改变化学分子链结构，保留原有高聚物的优点，是一种常用的高性能化方法，其中PLA/可生物降解聚酯共混体系的界面增容过程与机理的研究是共混改性中的基本科学问题。本课题设计合成了LIL、TSIL、PCL-b-PEG（IL）、PG34-b-PEG230-b-PG34等系列不同拓扑结构离子液体（TOILs），并将稀土发光元素引入到TOILs结构中，研究了TOILs分子链结构和离子液体基元对PLA聚集态结构的影响，并利用稀土示踪效应考察了上述因素对TOILs在PLA/可生物降解聚酯等共混物界面上的分散相容状态，对熔体冷却过程中聚合物大分子链缠结及链段的有序化过程的影响，对促进共混体系相界面构筑与多重强化增容的作用及机理等。.通过研究发现，在制备的TOILs中，LIL与TSIL可提高PLA的晶体生长速度，但其对PLA链段的有序化程度提高不明显。PCL-b-PEG（IL）中PEG链段及离子基元的协同塑化作用在提高PLA链段活性的基础上，由离子基元间非共价键形成的离子簇促进了PLA成核，将其引入PLA/PCL共混体系中发现，PCL-b-PEG（IL）对PLA/PCL体系具有较强的增容效果及界面乳化能力，并且PCL-b-PEG（IL）的强塑化及成核作用使PLA与PCL相的结晶度同时提高；嵌段聚电解质PG34-b-PEG230-b-PG34可在熔体中通过强静电相互作用，诱导PLA基体发生“多重成核”；同时，将含有稀土元素的杂化多酸（Eu-POM）引入到PLA/PG34-b-PEG230-b-PG34体系中，成功地对PLA的聚集体态演化过程进行了示踪；并在此基础上，将[COMIm][Br]引入PLA/EMA-GMA共混体系中，发现[COMIm][Br]可催化PLA/ EMA-GMA的界面增容，在界面处及基体内部形成三维化学交联网络及离子交联网络等强化增容结构，在[COMIm][Br]添加量为2%时样品的冲击强度提高了 23倍。本课题还拓展性地研究了TOILs对系列聚合物共混体系介电行为的影响，发现TOILs对多种聚合物共混体系的介电行为有良好的调控作用。.综上所述，本课题实现了TOILs对聚乳酸/可生物降解聚酯界面诱导与调控机理的研究，自课题实施以来，共计发表SCI论文22篇，EI论文1篇，取得了预期的研究成果，并为后续研究工作提供了基础。