Reorientational Dynamics of Dipolar Relaxations in Reactive Polymers

反应性聚合物中偶极弛豫的重新取向动力学

• 批准号: 9400716
• 负责人: Jovan Mijovic
• 金额: $ 19.29万
• 依托单位: Polytechnic University of New York
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-01 至 1997-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9400716&HistoricalAwards=false
• 关键词: Reorientational; Dynamics; Dipolar; Relaxations; Reactive

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.

Mijovic这项研究是在偶极弛豫过程的频域中反应系统的介电性质的分子和唯象方面。 这项工作涉及单官能（非聚合物形成反应物）和多官能或聚合物形成反应物。 该研究的独特之处在于，它将探测反应体系的确切分子组成，其中分子探针是偶极本身，并且在真实的时间内测量响应。 该分析是基于这样的前提下，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，以及它们的流动性的降低。 偶极子的再取向动力学将通过实验确定为反应时间和温度的函数，在很宽的频率范围内，将始终包括主要的弛豫过程。 将根据模型预测检查观察到的介电行为。 对于单官能反应配方，我们将寻求建立介电性能和已知的机械动力学之间的相关性。 多官能聚合物形成系统的建模将基于频率依赖性介电常数与其时间依赖性对应物之间的基本相关性，其将被适当地修改以解释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具有实用性，因为它将允许更好地控制其制造中的化学反应。