Exploring Polymer Dynamics in Solutions and Blends

将进行系统的工作来阐明在可混溶的A/B共混物中A和B的组分动力学如何不同地依赖于温度和组成，即，以揭示与A和B相关的摩擦因子各自如何随温度和组成而变化，并确定A和B是否在显著不同的温度下经历玻璃化转变。 聚合物增塑的概念尚未被证明是在聚合物组分具有显著不同温度的溶液中观察到的负特性粘度的起源。 聚合物A在溶液或共混物中的动力学是否完全取决于链间（外在）相互作用或进一步受链内（内在）相互作用的影响，从而它们与B的动力学不同，以及A是否在与B经历其玻璃化转变的温度不同的温度下经历玻璃化转变，这仍然是一个基本问题。 一种新的溶液流变学方法（SRA）将被应用于探讨这些问题。 为了描述在可混溶共混物（例如，由物质A和B组成），相应的“目标”和“镜像”溶液（例如，由聚合物A在低聚物B中和聚合物B在低聚物A中组成）分别进行研究，以解决A和B的组分动力学。 研究溶液动力学的协议，以获得明确的信息，相应的共混物的组分动力学代表了一个新的有吸引力的方法的主题，很少有实验技术已成功和有效地应用。 该SRA的优点是能够以最小的浓度波动确定组分动态，以及探测不混溶共混物中的组分动态。%拟议的研究的目的是实现新的理解聚合物动力学的解决方案和共混物是有关流变学和加工的聚合物材料。 这项工作的主题是聚合物科学和工程的核心，是聚合物材料研究的一个非常活跃的领域。 一个中心问题是如何预测分子混合聚合物共混物的整体粘弹性和单个组分的动力学，知道每个组分的玻璃化转变和粘弹性。

Systematic work will be carried out to elucidate how the component dynamics of A and B in a miscible A/B blend depend differently on temperature and composition, i.e., to uncover how friction factors associated with A and B each vary with the temperature and composition, and to determine whether A and B experience glass transition at significantly different temperatures. The concept of polymer plasticization is yet to proven as the origin of the negative intrinsic viscosity observed in solutions where the polymer component has a significantly different temperatures. It remains a fundamental question whether dynamics of polymer A in a solution or blend depend are completely determined by inter-chain (extrinsic) interactions or are further influenced by intra-chain (intrinsic) interaction so that they are from those of B and whether A undergoes the glass transition at a different temperature from that where B experiences its glass transition.. A novel Solution Rheology Approach (SRA) will be applied to probe these topics. To depict the separate component dynamics operative in miscible blends (e.g., made of species A and B), corresponding "object" and "mirror" solutions (e.g., made of polymeric A in oligomeric B and polymeric B in oligomeric A) will be investigated respectively to resolve the component dynamics of A and B. The protocol studying solution dynamics to gain explicit information about the component dynamics of corresponding blends represents a new attractive approach to the subject, to which few experimental techniques have been successfully and effectively applied. This SRA has the advantage of being able to determine the component dynamics with minimal concentration fluctuations as well as to probe component dynamics in immiscible blends.%%%The objective of the proposed research is to achieve new understanding of polymer dynamics in solutions and blends that are pertinent to rheology and processing of polymeric materials. The subject of the proposed work is at the heart of polymer science and engineering and is a very active area of polymer materials research. One central question is how to predict the overall viscoelasticity and individual component dynamics of a molecularly mixed polymer blend knowing the glass transition and viscoelastic properties of each component.