分子链缠结网络特性及其对结晶行为影响

Entanglement network in polymeric materials marks the main difference in the structures as compared with that of small molecular materials. Due to the existence of entanglement network, polymeric materials show much more complex structures of multi-layer or metastable state. It is widely known that almost all the properties of polymeric materials are, more or less, related to this complex entanglement network. Although this issue has been studied since the early stage of polymer science, the knowledge of entanglement network is still very limited until now. This situation, to a great degree, restrict our ability to understand many fundamental issues in polymer physics, such as crystallization behaviors, glass transition, rheological properties and so on. Therefore, this project is proposed to study the key issues about the entanglement network. It includes three aspects: Firstly, the establishment of a physical model of the entanglement network and the way to characterize its key properties; Secondly, how does the entanglement network develope from a less-entangled or disentangled state under different conditions (static or disturbed with controlled parameters); Lastly, the effects of entanglement state on the crystallization behaviors.

分子链缠结网络是高分子材料结构区别于小分子材料结构的关键所在。也正因为缠结网络的存在，高分子材料拥有比其它材料更加复杂的多层次结构或者亚稳态结构。众所周知，高分子材料几乎所有性能都或多或少与缠结网络结构有关。尽管聚合物缠结网络的研究几乎与聚合物科学同时进行，但时至今日，人们对于缠结网络的认识仍然非常有限。这也一定程度上限制了我们对聚合物结晶性能、玻璃化转变以及流变性能等基础高分子物理问题的认识。本项目针对分子链缠结网络的几个关键问题而展开。首先通过完善解缠结样品的制备方法，建立缠结网络结构发展的检测方法；其次是解缠结后的分子链如何再次形成缠结网络，即缠结网络的发展演变规律（分为静态和可控外界干扰条件下的演变规律）；最后讨论不同缠结状态对结晶聚合物结晶性能的影响。

分子链缠结网络是高分子材料结构区别于小分子材料结构的关键所在。也正因为缠结网络的存在，高分子材料拥有比其它材料更加复杂的多层次结构或者亚稳态结构。众所周知，高分子材料几乎所有性能都或多或少与缠结网络结构有关。尽管聚合物缠结网络的研究几乎与聚合物科学同时进行，但时至今日，人们对于缠结网络的认识仍然非常有限。这也一定程度上限制了我们对聚合物结晶性能、玻璃化转变以及流变性能等基础高分子物理问题的认识。本项目集中于讨论聚合物缠结网络结构发展的检测方法及聚合物缠结状态对其结晶行为的影响。项目执行过程中，以PLA为主要研究对象，建立了其缠结网络结构的检测方法，考察了分子量、测试参数等因素的影响规律；在此基础上，考察了缠结结构对PLA结晶动力学行为的影响，研究结果发表SCI收录论文1篇，EI收录3篇（含SCI收录1篇）；培养硕士研究生2名。