The Relation Between Atomic, Molecular Level and Macroscopic Descriptions of Stress in Dense Polymer Systems

致密聚合物体系中原子、分子水平和宏观应力描述之间的关系

• 批准号: 9908025
• 负责人: Catalin Picu
• 金额: $ 19.93万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-15 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9908025&HistoricalAwards=false
• 关键词: Relation; Between; Atomic; Molecular; Level

9908025The objective to develop a unified picture of stress production and relaxation in polymeric systems which will scale-link the atomic and molecular levels and will provide a framework in which the constitutive laws defined at larger scales will be based on atomic-scale processes. This effort is motivated by the challenges that the polymer industry faces when attempting to predict the processing behavior of a polymer melt from its molecular structure. The new physical picture to be developed will unify the description of the fast relaxation mode, which is related to local atomic rearrangements, and that of the slower short-time modes, which are related to bond and chain segment reorientation, will explicitly incorporate both intra-and inter-chain interactions accounting for excluded volume effects, and will lead to appropriate scaling laws. This formalism will be equally valid for short and long chain systems. Further, this description has to be in a format suitable for incorporation in continuum-like models in order to efficiently account for atomic-scale details within such macroscopic descriptions.

9908025的目标是开发一个统一的图片的应力产生和松弛的聚合物系统，这将规模链接的原子和分子水平，并将提供一个框架，在更大的尺度上定义的本构关系将基于原子尺度的过程。这一努力的动机是聚合物工业在试图从其分子结构预测聚合物熔体的加工行为时所面临的挑战。要开发的新的物理图像将统一描述的快速弛豫模式，这是有关本地原子重排，和较慢的短时间模式，这是有关键和链段的重定向，将明确纳入链内和链间的相互作用占排除体积效应，并会导致适当的标度律。这种形式主义对短链和长链系统同样有效。此外，这种描述必须采用适合于结合在连续体类模型中的格式，以便在这种宏观描述中有效地考虑原子尺度的细节。