Abstract:
Staudinger taught us that macromolecules were made up of covalently bonded monomer repeat units chaining up as polymer chains. This paradigm is not challenged in this paper. The main question raised in polymer physics remains: how do these long chains interact and move as a group when submitted to shear deformation at high temperature when they are viscous liquids? The current consensus is that we need to distinguish two cases: the deformation of \"un-entangled chains\" for macromolecules with molecular weight, M, smaller than Me, \"the entanglement molecular weight\", and the deformation of \"entangled\" chains for M > Me. The current paradigm stipulates that the properties of polymers derive from the statistical characteristics of the macromolecule itself, the designated statistical system that defines the thermodynamic state of the polymer. The current paradigm claims that the viscoelasticity of un-entangled melts is well described by the Rouse model and that the entanglement issues raised when M > Me, are well understood by the reptation model introduced by de Gennes and colleagues. Both models can be classified in the category of \"chain dynamics statistics\". In this paper, we examine in detail the failures and the current challenges facing the current paradigm of polymer rheology: the Rouse model for un-entangled melts, the reptation model for entangled melts, the time-temperature superposition principle, the strain-induced time dependence of viscosity, shear-refinement and sustained-orientation. The basic failure of the current paradigm and its inherent inability to fully describe the experimental reality is documented in this paper. In the discussion and conclusion sections of the paper, we suggest that a different solution to explain the viscoelasticity of polymer chains and of their \"entanglement\" is needed. This requires a change in paradigm to describe the dynamics of the interactions within the chains and across the chains. A brief description of our currently proposed open dissipative statistical approach, \"the Grain-Field Statistics\", is presented.
摘要:
Staudinger告诉我们,大分子是由共价键合的单体重复单元组成的,这些单元链接为聚合物链。这种范式在本文中没有受到挑战。聚合物物理学中提出的主要问题仍然是:当它们是粘性液体时,当它们在高温下经受剪切变形时,这些长链如何相互作用和作为一个群体移动?目前的共识是我们需要区分两种情况:分子量大分子的“未缠结链”的变形,M,比我小,“纠缠分子量”,以及M>Me的“纠缠”链的变形。目前的范式规定,聚合物的性质来源于大分子本身的统计特征,定义聚合物热力学状态的指定统计系统。当前的范式声称,Rouse模型很好地描述了未缠结熔体的粘弹性,并且当M>Me时提出了缠结问题,由deGennes和他的同事们介绍的复制模型很好地理解了这一点。这两种模型都可以归类为“链动态统计”类别。在本文中,我们详细研究了当前聚合物流变学范式面临的失败和当前挑战:未缠结熔体的Rouse模型,纠缠熔体的复制模型,时间-温度叠加原理,应变引起的粘度的时间依赖性,剪切细化和持续取向。本文记录了当前范式的基本失败及其固有的无法完全描述实验现实。在本文的讨论和结论部分,我们建议需要一种不同的解决方案来解释聚合物链及其“缠结”的粘弹性。这需要改变范式来描述链内部和链之间的相互作用的动态。简要介绍了我们目前提出的开放耗散统计方法,“粮田统计”,是presented。