Reorientational Dynamics of Dipolar Relaxations in Reactive Polymers

米约维奇这项研究是关于偶极驰豫过程频域中反应体系介电性质的分子和唯象方面的研究。这项工作既涉及单官能团(非聚合物形成反应物)，也涉及多官能团或聚合物形成反应物。这项研究的独特之处在于，它将探测反应体系的确切分子组成，其中分子探测器是偶极本身，反应是实时测量的。分析的前提是，反应过程中的介电响应必须反映偶极子的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在一个始终包括主要弛豫过程的宽频率范围内的函数。观察到的介电行为将与模型预测进行核对。对于单官能团反应配方，我们将寻求在介电性质和已知的机理动力学之间建立关联。多功能聚合物形成体系的建模将基于频率相关的介电常数与其时间相关的介电常数之间的基本相关性，并将对其进行适当修改，以考虑反应聚合物中松弛时间的分布。这项基础研究在聚合物基复合材料的制备中是有用的，因为它将允许更好地控制其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.