ABSTRACT

A method for predicting the optimal conditions for polymer extrusion, which relies only on gramscale laboratory experiments for two commercial polystyrene samples with two molecular weights is demonstrated by oscillatory rheology. These enable a shear viscosity map vs. temperature and shear rate to be constructed, together with the positions for the major molecular timescales. Alternative methods for characterising rheology, including melt flow index and capillary rheology measurements were also employed, but these do not give the same level of understanding of flow behaviour. The capillary tests generates die swell and this complex behaviour can be seen to collapse onto a single line regardless of temperature when plotted using the Rouse–Weissenberg number. The full shear viscosity map, together with the polymer timescales serves as a design tool to predict processing behaviour for melt processors. The work represents and builds on major academic-industry collaborative research programmes.

摘要

振荡流变学证明了一种预测聚合物挤出最佳条件的方法，该方法仅依赖于对两种具有两种分子量的商业聚苯乙烯样品的克级实验室实验。这些能够构建剪切粘度图与温度和剪切速率的关系，以及主要分子时间尺度的位置。还采用了表征流变学的替代方法，包括熔体流动指数和毛细管流变学测量，但这些方法对流动行为的理解程度不同。毛细管测试会产生模具膨胀，当使用 Rouse-Weissenberg 数绘制时，无论温度如何，都可以看到这种复杂的行为塌陷成一条线。完整的剪切粘度图，与聚合物时间尺度一起用作预测熔体处理器加工行为的设计工具。这项工作代表并建立在主要的学术与行业合作研究计划之上。