Living Polyisonitrile Polymerization Catalysts

活性聚异腈聚合催化剂

• 批准号: 9023253
• 负责人: Bruce Novak
• 金额: $ 17.2万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9023253&HistoricalAwards=false
• 关键词: Living; Polyisonitrile; Polymerization; Catalysts

With support from the Organic Dynamics Program, Dr. Novak will investigate the design, preparation, and implementation of organometallic catalysts for the "living" polymerization of monomers known to yield stable, helical polymers. Specifically, new Ni(I) and Ni(II) catalysts for the polymerization of isonitriles will be investigated. Detailed mechanistic studies will be performed in an effort to provide the information necessary to modify these new catalysts for specific applications. The basic premise of Dr. Novak's study is that organometallic complexes, which possess versatile coordination spheres and oxidation states, can be used to alter the reactivity of polymer endgoups in a predictable manner and with a high degree of precision. Depending upon the requirements of the particular reaction, the organometallic species may be called upon to either activate or deactivate the polymer endgroup. Dr. Novak's study is designed to provide a means by which endgroups can be rendered unreactive toward all processes other than the desired initiation and propagation steps that lead to polymer formation. %%% The ultimate polymerization catalysts for the controlled synthesis of well-defined macromolecules are "living". Living polymerizations can be used to synthesize macromolecules with pre-determined molecular weights, narrow chain-length distributions, and defined endgroups. In addition, living systems allow the precise synthesis of "block copolymers", which offer a combination of properties unobtainable from simple polymer blends or random copolymers. Dr. Novak will utilize this approach for controlled synthesis of polyiso- nitriles, an important class of soluble polymers. In addition, the living nature of his approach will be exploited in the preparation of novel di- and tri-block copolymers, which are of interest as a new class of thermoplastic elastomers.

在有机动力学计划的支持下，Novak博士将研究有机金属催化剂的设计，制备和实施，以实现已知可产生稳定的螺旋聚合物的单体的“活”聚合。具体而言，将研究新的Ni（I）和Ni（II）催化剂，用于聚合异构体的聚合。将进行详细的机械研究，以提供为特定应用修改这些新催化剂所需的信息。 Novak博士的研究的基本前提是，具有多功能配位球和氧化状态的有机金属配合物可用于以可预测的方式和高度的精度来改变聚合物最终目标的反应性。根据特定反应的要求，可以要求有机金属物种激活或停用聚合物端基。 Novak博士的研究旨在提供一种手段，除了导致聚合物形成的所需启动和传播步骤以外，端群可以对所有过程产生不反应。 %% %%，用于控制良好定义的大分子的控制合成的最终聚合催化剂是“活的”。活性聚合可用于与预定的分子量，狭窄的链长分布和定义的端群合成大分子。此外，生活系统允许精确合成“块共聚物”，从而提供了简单聚合物混合物或随机共聚物无法获得的特性组合。 Novak博士将利用这种方法来控制一类可溶性聚合物多硝基的合成。此外，他的方法的生命性将在制备新型二键和三块共聚物时被利用，这是一种新型的热塑性弹性体。