Birefringence and Light-Scattering Studies of Concentrated Polymer Solutions in Strong Flows

本研究对浓聚聚合物溶液在强流动中的作用进行了实验和理论研究。目的是更好地理解由于流动而发生的聚合物构象的变化，反过来，由于聚合物而发生的流动的改变。提出的实验测量利用双色双折射系统来提供瞬态条件下聚合物构象的实时数据，并利用动态光散射来获得流动中速度梯度的局部瞬时数据。从基本观点来看，关注的是分子参数之间的关系，特别是分子量和分子量分布，在所谓的“粘弹性”状态下从平衡状态产生大变形的聚合物弛豫现象。从更广泛的意义上讲，该研究涉及各种流动对聚合物构象的影响，以及对聚合物加工的影响，包括通过流动诱导的构象修饰来操纵聚合物材料宏观性质的潜力。

This research deals with an experimental and theoretical study of concentrated polymer solutions in strong flows. The objective is a better understanding of the changes in polymer conformation which occur as a consequence of the flow, and conversely, the modifications of the flow which occur because of the polymer. The proposed experimental measurements utilize a two-color birefringence system to provide real-time data on polymer conformation in transient conditions, and dynamic light scattering to obtain local, instantaneous data on the velocity gradient in the flow. From a fundamental point of view, the concern is with the relationship between molecular parameters, particularly the molecular weight and molecular-weight distribution, on polymer relaxation phenomena in the so-called "viscoelastic" regime of large deformation from the equilibrium state. In a more general sense, the research deals with the effects of various kinds if flow on polymer conformation, and with the implications for polymer processing, including the potential for manipulation of macroscopic properties of polymeric materials through flow-induced modifications of conformation.