Anisotropic Thermal Conductivity in Shear Deformations of Polymer Melts

变形聚合物中的各向异性热传导聚合物分子的流动取向导致其力学、光学和热性能的各向异性，并对材料性能产生深远的影响。本研究的目的是获得定量的，随时间变化的热扩散张量在变形的聚合物液体。这些测量将使用一种称为强迫瑞利散射的非侵入性光学技术进行。实验将对几种聚合物熔体在阶梯剪切应变和稳定剪切速率流动停止下进行。热扩散张量的测量分量将与机械（应力）和光学（双折射）数据结合使用，以评估应力-热规律。了解聚合物加工过程中发生的流动诱导取向与其最终用途物理性质之间的联系至关重要。本研究中获得的热扩散张量测量结果将大大加强制定有物理意义的过程流模型的努力，这些模型可用于开发先进的加工技术和应用。

Abstract for Venerus' project0075789 Anisotropic Thermal Conduction in Deforming PolymersFlow-induced orientation of polymeric molecules results in anisotropic mechanical, optical and thermal properties and has profound effects on material properties. The objective of this study is to obtain quantitative, time-dependent measurements of the thermal diffusivity tensor in deforming polymer liquids. These measurements will be made using a non-invasive optical technique known as Forced Rayleigh Scattering. Experiments will be conducted on several polymer melts in step-shear strain and cessation of steady shear rate flows. Measured components of the thermal diffusivity tensor will used in conjunction with mechanical (stress) and optical (birefringence) data to evaluate the stress-thermal rule. Understanding the connection between the flow-induced orientation that occurs during processing of polymers and their end-use physical properties is essential. The thermal diffusivity tensor measurements obtained in this study will significantly enhance efforts to formulate physically-meaningful process flow models that can be used for the development of advanced processing technologies and applications.