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

这个学术界与工业界联系的资助机会（GOALI）项目涉及聚合物加工中的两个重要问题。研究的重点是通过开发一种新的间接测量聚合物材料拉伸粘度的方法来加强对加工过程的控制。此外，努力优化聚合物挤出模具通道的几何形状将在拉伸粘度对聚合物在模具中流动的影响方面进行研究。 在该项目中，拉伸粘度的应变率依赖性将通过寻找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毛细管或狭缝流变仪的相应实验数据之间的差异最小化。预计将提供比使用目前可用的软件包获得的设计更好的模具设计，该软件包不考虑聚合物的拉伸粘度。即使这一建议涉及挤出模头的优化，所提出的研究的成功完成将开辟的途径，包括拉伸粘度对设备的设计，涉及拉伸为主的流动，如吹塑和纤维纺丝的其他聚合物加工技术的影响。 本计画所开发之软体将应用于高年级课程中，以教育学生拉伸黏度在聚合物加工中之重要性。 在接下来的三年里，一名研究生将每年在陶氏化学公司花一个月的时间进行各种实验，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.