聚合物体系拉伸流变行为的表征及研究进展

Extensional Rheology of Polymer Systems:Characterization and Progress

聚合物的拉伸流动在吹膜、纺丝、热成型等加工中扮演着支配的角色,因此掌握聚合物熔体在拉伸条件下的流动行为对于控制和预测其加工性能具有重要意义。相对于剪切流动,拉伸粘度对于大分子的结构、填充粒子的各向异性、共混物中两相的结构等更加敏感。本文简要介绍了当前用于拉伸流变研究的常用装置及其原理,并举例描述了单一组分聚合物、聚合物纳米复合材料和聚合物共混物等体系拉伸流变研究的现状和成果,最后指出了当前拉伸流变研究领域存在的一些不足之处并进行了展望。

Extensional flow of polymer melts play a dominant role in polymer processes such as film blowing, fiber spinning and thermoforming. Knowing the extensional flow properties of the polymer melts is very important to control and predict their ability to be shaped or processed into products. In many cases and compared to shear flow, transient extensional viscosity is more sensitive for characterizing polymer structures such as macromolecular structure, anisotropy of particles filling and phase morphology of polymer blends. In this paper, the extensional rheometers or fixtures commonly used and their principles are briefly introduced. Moreover, some recent investigations about the extensional flow properties of pure polymers, polymer nanocomposites and polymer blends are reviewed and discussed.