An Integrated Theoretical and Experimental Study of a Free Radical Polymerization and Polymer Reaction Kinetics

提出了一个实验与理论相结合的方案，其目标是在密切耦合的自由基聚合（FRP）和聚合物反应动力学领域取得根本性进展。物理和化学在这些现象中起着同样重要的作用。相应地，该计划联合并协调了实验光化学家（NJT）和理论聚合物物理学家（BOS）的努力，他们在反应聚合物系统方面具有丰富的经验。在前期资助期内已完成的研究中，进行实验。理论、化学和物理一直分不开。FRP的复杂工艺涉及到聚合物科学和自由基化学的许多基本方面。生长中的聚合物之间的反应起着至关重要的作用，这些聚合物携带着被称为“活链”或“自由基”的末端基团。因此，FRP与一般聚合物反应动力学领域是紧密交织在一起的。由于FRP中的活链寿命较短，其分子量分布（MWD）从未被测量过。在上一个资助期内，首次开发了一种测量FRP活mwd的方法。激光光解用于“影印”瞬时活种群到荧光标记的死链种群，这可以通过标准方法进行分析。在拟议的研究中，线性FRP的活mwd将在已知长度和浓度的预先准备的死链背景中进行复印。将对稳态FRP和非稳态FRP进行影印和其他光谱测量，这些FRP是由闪光光解产生的高度新颖的初始条件演变而来的。理论将试图预测这些实验的结果，扩展在第一个资助时期发展起来的理论，处理非常稀的死背景。在某种程度上，这些实验使我们能够直接研究尚未解决的基本问题，这在以前是不可能的。例如，分别在纠缠和未纠缠的死矩阵中进行复印，将提供对缠绕在FRP中的作用和著名的凝胶效应性质的独特研究。第二个家族的项目将解决基本的聚合物反应动力学。如果成功，这些测量将对反应聚合物体系和聚合物物理学领域产生重大影响，因为几乎所有关于k和k(t)的理论预测都从未被测试过。有机和大分子化学项目通过这个奖项来支持哥伦比亚大学化学系Nicholas J. Turro教授和Ben O’shaughnessy教授的研究。这项研究的独特之处在于它提供了一个应用理论和实验努力来理解自由基聚合机制的机会。玻璃钢在聚合物工业中具有巨大的技术重要性，用于合成大量的聚合物材料。实验光化学家的专业知识将与理论聚合物物理学家的专业知识相结合，提供一个跨学科的环境，让参与的学生在研究的两个方面都得到培训。

An integrated program of experiment and theory is proposed whose objective is fundamental progress in the closely coupled fields of Free Radical Polymerization (FRP) and Polymer Reactions Kinetics. Physics and chemistry play equally central roles in these phenomena. Correspondingly, the program unites and coordinates the efforts of an experimental photochemist (NJT) and a theoretical polymer physicist (BOS) with extensive experience in reacting polymer systems. In the accomplished research during the previous funding period, experiment. theory, chemistry and physics have been inseparable. The complex processes in FRP involve many fundamental aspects of polymer science and radical chemistry. A crucial role is played by reactions between growing polymers carrying radical end groups, known as "living chains" or "macroradicals." For this reason, FRP and the general field of polymer reaction kinetics are deeply intertwined.Since the living chains in a FRP have short lifetimes, their molecular weight distributions (MWD) have never been measured. In the previous funding period a method was developed to measure FRP living MWDs for the first time. Laser photolysis is used to "photocopy" the transient living population into a fluorescence-labeled dead chain population, which can be analyzed by standard methods. In the proposed research, living MWDs of linear FRP will be photocopied in pre-prepared dead chain backgrounds of known length and concentration. Photocopies and other spectroscopic measurements will be made of steady state FRP, and of non-steady state FRPs evolving from highly novel initial conditions created by flash photolysis. Theory will attempt to predict the outcome of these experiments, extending the theory developed in the first funding period dealing with very dilute dead backgrounds. The experiments enable direct examination of fundamental unresolved issues in a way, which has not been possible until now. For example, photocopying in entangled and unentangled dead matrices, respectively, will provide a unique examination of the role of entanglements in FRP and the nature of the celebrated gel effect. A second family of projects will address fundamentals of polymer reaction kinetics. If successful, these measurements will have significant impact on the field of reacting polymer systems and polymer physics in general since virtually all theoretical predictions on k and k(t) have never been tested.With this award the Organic and Macromolecular Chemistry Program is supporting the research of Professors Nicholas J. Turro and Ben O'Shaughnessy of the Department of Chemistry at Columbia University. This research is unique in that it provides an opportunity to apply theoretical and experimental efforts to understanding the mechanism of free radical polymerizations. FRP is of enormous technological importance in the polymer industry, used to synthesize a great number of polymeric materials. The expertise of an experimental photochemist will combine with that of a theoretical polymer physicist to provide an interdisciplinary environment where the students involved will be trained in both aspects of the research.