Experimental and Theoretical Studies of Concentrated PolymerSolutions in Strong Flows

迫切需要开发一种技术， 以更快的速度处理聚合物，这将导致 具有较高分子取向度的聚合物材料。 这些进步将使现有的工艺更具竞争力， 将增加制造有价值的新产品的前景， 产品. 这些目标有可能实现，如果 高应变率下研究聚合物的实验技术 并将由此产生的信息用于制定 聚合物液体如何流动的微观理解。 这 该项目旨在提供这些基本知识。 它 描述了分子和流体的实验研究工作 聚合物液体的力学受到流动类型， 剪切和延伸的混合物通常在商业中发现， 处理操作。 实验将使用 一系列的技术，最重要的参数影响 流变学响应：缠结密度和分子量 分布 这种类型的资料库， 良好表征的分子结构是研究 点 由此获得的分子理解将用于 继续开发项目中描述的模型。 的 最终目标是要有一个详细的了解高度 在这些条件下存在的非线性响应，并使用 设计新的处理程序， 优化聚合物的宏观性能。 这项研究是由聚合物计划联合支持， 材料研究与流体、颗粒和 化工与热工系液压系统项目 系统.

A critical need exists to develop the technology that will allow processing polymers at faster speeds and that will result in polymeric materials with higher degrees of molecular orientation. Such advances will make existing processes more competitive and will increase the prospects for manufacturing valuable new products. It is likely that these goals can be reached if experimental techniques for studying polymers at high strain rates are improved and the resulting information is used to develop a microscopic understanding of how polymer liquids flow. This project is intended to provide this fundamental knowledge. It describes experimental research work on the molecular and fluid mechanics of polymeric liquids subjected to flow types that contain a mixture of shear and extension typically found in commercial processing operations. The experiments will investigate, using a range of techniques, the most important parameters affecting the rheological response: entanglement density and molecular-weight distribution. A data base of this type on materials that have well-characterized molecular structures is the necessary starting point. The molecular understanding so obtained will be used to continue the development of models described in the project. The ultimate goal is to have a detailed understanding of the highly nonlinear response that exits under these conditions and to use this information to devise new processing procedures that will optimize the macroscopic properties of polymers. This research is jointly supported by the Polymers Program in the Division of Materials Research and the Fluid, Particulate and Hydraulic Systems Program of the Division of Chemical and Thermal Systems.