Reorientational Dynamics of Dipolar Relaxations in Reactive Polymers

这项研究是在偶极子弛豫过程的频域上反应体系介电特性的分子和现象学方面。这项工作涉及单功能（非聚合物形成反应物）和多功能或聚合物形成反应物。该研究的独特之处在于它将探测反应系统的确切分子组成，其中分子探针是偶极子本身，并且实时测量响应。分析的前提是，反应过程中的介电响应必须反映偶极子类型和浓度的变化及其迁移率的降低。偶极子的重定向动力学将被实验确定为反应时间和温度的函数，在一个很宽的频率范围内，将始终包括主要的弛豫过程。观察到的介电行为将与模型预测相核对。对于单功能反应式，我们将寻求建立介电性质和已知力学动力学之间的相关性。多功能聚合物形成系统的建模将基于频率相关的介电常数与其时间相关的对应物之间的基本相关性，并将适当修改以考虑反应性聚合物中弛豫时间的分布。这项基础研究在聚合物基复合材料的制备中很有用，因为它可以更好地控制制造过程中的化学反应。

Mijovic This research is on molecular and phenomenological aspects of dielectric properties of reactive systems in the frequency domain of the dipole relaxation process. The work concerns both monofunctional (non-polymer forming reactants) and multifunctional or polymer forming reactants. The unique feature of the investigation is that it will probe the exact molecular make-up of the reactive system, where the molecular probe is the dipole itself and the response is measured in real time. The analysis is based upon the premise that the dielectric response in the course of reaction must reflect a change in the type and concentration of dipoles and a decrease in their mobility. Reorientational dynamics of dipoles will be experimentally determined as a function of reaction time and temperature over a wide frequency range that will always include the major relaxation process. The observed dielectric behavior will be checked against model predictions. For the monofunctional reactive formulation, we shall seek to establish correlations between the dielectric properties and the known mechanistic kinetics. Modelling of the multifunctional polymer forming system will be based upon the fundamental correlation between the frequency-dependent dielectric constant and its time- dependent counterpart, which will be appropriately modified to account for the distribution of relaxation times in reactive polymers. %%% This fundamental research is of utility in the preparation of polymer-matrix composites in that it will allow a better control of the chemical reactions in their manufacture.