Macromolecular Engineering by Controlled/Living Radical Polymerization

技术综述受控/活性自由基聚合(CRP)是化学中发展最快的领域之一。CRP是一种强大的合成技术，可用于制备许多定义明确的大分子结构，并可用于生产新的特种材料。这项建议的主要目的是探索几个分子结构参数对一系列新材料的形态和性能的影响，这些新材料是专门设计、制备和表征的，以扩大对材料性能如何发展的了解。主要的智力挑战是精确控制分子结构，并确定链一致性、组成或拓扑方面的缺陷将如何影响某些宏观性质。两个或两个以上不相容的单体将以统计、梯度、多嵌段和嵌段的方式进行共聚；得到的共聚物将被表征；它们的形态以及它们的热机械和其他物理性能将被研究。将使用可产生高和低玻璃化转变温度的无定形聚合物，但也可结晶的单体和将形成两亲性体系的单体。将测定星形嵌段共聚物的支化效应和臂数对共聚物光谱性质的影响。将制备新的miktoarm星形聚合物，并详细分析合成过程中的变化如何影响它们的结构和一些性能。(2)合成具有较低临界溶解温度(LCST)的聚合物，研究单体在共聚物中的序列分布和分子结构对LCST行为的影响。将评估具有各种可降解连接物的模型聚合物的降解速率，并建立它们的结构与依赖于pH的降解速率之间的关联。这些可降解单元将以受控的方式结合到聚合物片段中，以制备可降解的乙烯基聚合物。非技术性总结这项提议的结果将产生更广泛的影响，通过教育研究生、本科生和博士后研究员，通过及时的出版物(包括《J.Chem.Ed.》)、互联网和在(国际)国家研讨会和CMU推广计划上的演讲来传播在该项目中产生的信息。将继续与受益于NSF支持的活动产生的所有知识的约10家公司组成CRP联盟。这项拟议研究的影响将超越合成聚合物化学。它可能会影响材料科学的基本概念，并导致一些有商业价值的材料的开发。

TECHNICAL SUMMARYControlled/Living Radical Polymerization (CRP) is among the most rapidly developing areas of chemistry. CRP is a powerful synthetic technique for preparation of many well-defined macromolecular structures and can be used to produce new specialty materials. The main objective of this proposal is to explore the effect of several molecular structural parameters on the morphology and properties of a range of new materials that were specifically designed, prepared and characterized to expand the knowledge of how the properties of material develop. The main intellectual challenge is to precisely control the molecular structure and also to determine how imperfections in chain uniformity, composition or topology will affect some macroscopic properties. Two or more incompatible monomers will be copolymerized in statistical, gradient, multisegmented and blocky ways; the resulting copolymers will be characterized; their morphology as well as their thermomechanical and other physical properties will be studied. Monomers which yield amorphous polymers with high and low glass transition temperature but also monomers which can crystallize and those which will form amphiphilic systems will be used. The effect of branching and the effect of the number of arms in star-block copolymers on the properties of a spectrum of copolymers will be cdetermined. New miktoarm star polymers will be prepared and analyzed in detail how variations in the synthetic procedure can affect their structure and some of their properties. (Co)polymers which exhibit lower critical solution temperature (LCST) will be synthesized and the effect of sequence distribution of monomers in the copolymer and molecular architecture on LCST behavior will be studied. The degradation rate of model polymers, with various degradable linkers, will be evaluated and a correlation between their structure and pH dependent degradation rate will be devloped. These degradable units will be incorporated into polymer segments in a controlled fashion to prepare degradable vinyl polymers. NON-TECHNICAL SUMMARYThe results from this proposal will generate broader impact by educating graduate, undergraduate students and postdoctoral fellows, by dissemination information generated in this project via timely publications (including "J. Chem. Ed."), internet and presentations at (inter)national symposia and CMU outreach programs. CRP Consortium with ~ 10 companies which benefit from all knowledge generated by NSF supported activities will be continued. The impact of the proposed research will extend beyond synthetic polymer chemistry. It could affect basic concepts in materials science and lead to the development of some commercially valuable materials.