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

点击翻译按钮获取中文摘要

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.