Experimental and Theoretical Studies of Polymeric Liquids in Extension-Dominated Fluids

小行星9700034 该GOALI奖的最终目标（由材料研究部和多学科活动办公室联合支持）是开发一种预测基础，以描述线性链柔性聚合物在拉伸或拉伸主导的流动中的行为。 主要的重点是解决方案，是充分进入角，reptation为基础的理论，预计将适用。 拟议的实验研究利用了一种新的组合的流动池，称为2-和4-辊米尔斯，旨在产生纯拉伸，或拉伸为主，二维流动，也可以是稳定的，或随时间变化的;和光学技术，可以探测链配置和实际的速度梯度在任何点内的流动池。 链配置推断从双色双折射测量的流体中的光学各向异性的程度。动态光散射的一个独特的实现提供了一个逐点测量的速度梯度，无论是稳定或瞬态流。 与理论模型进行比较，通过全场流体动力学模拟的稀释，博格型流体。对于单分散和双分散纠缠的解决方案，测量的生物分形数据与模型预测使用测量的速度梯度数据作为输入进行比较，基于爬行的模型。 %从技术的角度来看，预测聚合物液体在拉伸流动中的行为的能力将有助于了解材料特性和加工之间的关系。 从教育的角度来看，这个GOALI项目提供了增强正常的博士学位。程序. 研究生将在埃克森公司研究实验室居住长达一年的时间，在那里他们将直接与斯科特米尔纳合作，并参观埃克森研究实验室在贝敦，那里的工作正在进行的聚合物合成和聚合物加工问题，直接关系到这个项目的基本目标。 ***

9700034 Leal The ultimate objective of this GOALI award (supported jointly by the Division of Materials Research and the Office of Multidisciplinary Activities) is the development of a predictive basis to describe the behavior of solutions of linear-chain, flexible polymers in flows that are either extensional or extension-dominated. The primary emphasis is on solutions that are sufficiently ent angled that reptation-based theories are expected to apply. The proposed experimental studies utilize a novel combination of flow cells, known as 2- and 4- roll mills, that are designed to produce pure extensional, or extension-dominated, two-dimensional flows, that can also be either steady, or time-dependent; and optical techniques that can probe the chain configuration and the actual velocity gradient at any point within the flow cell. Chain configuration is inferred from two-color birefringence measurements of the degree of optical anisotropy in the fluid. A unique implementation of dynamic light scattering provides a pointwise measure of the velocity gradient for either steady or transient flows. Comparisons with theoretical models are made via full-field fluid dynamics simulations for the dilute, Boger-type fluids. For reptation-based models of monodisperse and bi-disperse entangled solutions, measured biorefringence data is compared with model predictions using the measured velocity gradient data as input. %%%% From a technological point of view, the ability to predict the behavior of polymeric liquids in extensional flows would allow an understanding of the relationship between material characteristics and processing. From an educational standpoint, this GOALI project offers enhancements to the normal Ph.D. program. Graduate students will spend up to a year in residence at the Exxon Corporate Research Laboratory, where they will work directly with Scott Milner, as well as visiting the Exxon Research Labs at Baytown where work is being carried out on both polymer synthesis and polymer processing issues that are directly related to the fundamental objectives of this project. ***