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

提出了一个实验和理论相结合的计划，其目标是在自由基聚合（FRP）和聚合物反应动力学的密切耦合领域的基础性进展。物理学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）和在聚合物反应系统方面拥有丰富经验的理论聚合物物理学家（BOS）的努力。在上一个资助期内完成的研究中，进行实验。理论、化学和物理学是密不可分的。FRP中的复杂工艺涉及聚合物科学和自由基化学的许多基本方面。一个关键的作用是由携带自由基端基的聚合物之间的反应，称为“活链”或“大自由基”。因此，FRP和聚合物反应动力学领域紧密相连。由于FRP中的活性链寿命短，因此从未测量过它们的分子量分布（MWD）。在上一个供资期间，首次开发了一种测量FRP活MWD的方法。激光光解用于将短暂的活种群“影印”成荧光标记的死链种群，可以通过标准方法进行分析。在拟议的研究中，线性玻璃钢的活MWD将在预先准备的已知长度和浓度的死链背景中进行复印。将对稳态玻璃钢和从闪光光解产生的高度新颖的初始条件发展而来的非稳态玻璃钢进行影印和其他光谱测量。理论将试图预测这些实验的结果，扩展在第一个资助期内开发的理论，处理非常稀释的死亡背景。这些实验使人们能够以一种直到现在还不可能的方式直接研究根本的未解决问题。例如，在纠缠和未纠缠的死矩阵，分别影印，将提供一个独特的审查的作用，纠缠在玻璃钢和著名的凝胶效应的性质。第二个系列的项目将解决聚合物反应动力学的基本原理。如果成功的话，这些测量将对反应聚合物系统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。有了这个奖项，有机和大分子化学计划将支持哥伦比亚大学化学系的Nicholas J. Turro和Ben O'Shaughnessy教授的研究。这项研究是独特的，因为它提供了一个机会，应用理论和实验的努力，以了解自由基聚合的机制。FRP在聚合物工业中具有巨大的技术重要性，用于合成大量聚合物材料。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结合联合收割机，以提供一个跨学科的环境，参与的学生将在研究的两个方面进行培训。

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.