GOALI: Optimum Design of Extrusion Dies using the Estimated Elongational Viscosity of Polymers

这个学术与工业联系机会(GOALI)项目涉及聚合物加工中的两个重要问题。研究的重点将是通过开发一种间接测量聚合物材料拉伸粘度的新方法来加强对加工的控制。此外，还将根据拉伸粘度对口模中聚合物流动的影响来研究优化聚合物挤出口模通道几何形状的努力。在本项目中，拉伸粘度的应变率相关性将通过寻找Sarkar-Gupta拉伸粘度模型中四个参数的最佳值来确定，从而使有限元模拟预测的压力损失与来自毛细管或狭缝流变仪的相应实验数据之间的差异降至最小。优化模型将在本项目中开发，预计将提供比使用现有软件包获得的模具设计更好的模具设计，后者不考虑聚合物的拉伸粘度。尽管这项建议涉及挤出模具的优化，但建议研究的成功完成将为包括拉伸粘度对其他聚合物加工技术设备设计的影响开辟道路，其他聚合物加工技术涉及拉伸为主的流动，如吹塑和纤维纺丝。本项目开发的软件将用于一门高级课程，教育学生拉伸粘度在聚合物加工中的重要性。在接下来的三年里，一名研究生将每年花一个月的时间在陶氏化学公司进行各种实验，从而从该项目中获得额外的教育收益。

This Grant Opportunity for Academic Liaison with Industry (GOALI) project deals with two important issues in polymer processing. Research will be focused on enhancing the control of the processing through the development a new methods for indirect measurement of the elongational viscosity of the polymeric material. In addition, efforts to optimize die channel geometry for polymer extrusion will be investigated in terms of the effects of elongational viscosity on the polymer flow in the die. In this project, strain-rate dependence of elongational viscosity will be determined by finding the optimal values of the four parameters in the Sarkar-Gupta elongational viscosity model such that the difference between the pressure loss predicted by a finite element simulation and the corresponding experimental data from a capillary or slit rheometer is minimized.The optimization model, which will be developed in this project, is expected to provide much better die design than the design obtained by using currently available software packages, which do not account for the elongational viscosity of a polymer. Even though this proposal involves optimization of extrusion dies, a successful completion of the proposed research will open the avenues for including the effect of elongational viscosity on design of the equipment for other polymer processing techniques involving elongation-dominated flows such as blow molding and fiber spinning. The software developed in this project will be used in a senior-level course to educate the students on importance of elongational viscosity in polymer processing. For the next three years, a graduate student will spend one month per year at The Dow Chemical Co. to conduct various experiments resulting in additional educational benefit from the project.