Polymers of Unusual Topology using Heterogeneous ROMP Catalysts

使用异质 ROMP 催化剂的异常拓扑聚合物

基本信息

批准号：
1807154
负责人：
Robert Grubbs
金额：
$ 64万
依托单位：
California Institute of Technology
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2022-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807154&HistoricalAwards=false
关键词：
Polymers Unusual Topology using Heterogeneous

项目摘要

Polymers are ubiquitous in our everyday lives. They are plastics, rubbers or gels, and in living systems they serve a structural role as proteins, and also the source of genetic information as DNA and RNA. Small chemical units (monomers) are linked together to produce a polymer with any number of desired functions. The characteristics of the polymer are determined both by the monomer, and how the monomer units are connected. Professor Grubbs at the California Institute of Technology in Pasadena, CA develops new methods for producing polymers, specifically on developing new types of polymers with complex structures which generate new materials for important commercial and academic uses. One important approach involves very long polymer chains where the ends are connected, so that the resulting cyclic polymer does not have a beginning or end. These polymers are challenging to produce. Many theories suggest cyclic polymers will have different properties than identical polymers where the ends are not connected. Polymers with enhanced properties are anticipated to result from this work. This project provides an excellent platform for research training of scientists and helps to prepare a skilled workforce for academia and industry.Ring-opening metathesis polymerization (ROMP) is a critical tool in polymer synthesis and is used to produce numerous model systems, as well as a number of commercial materials. Most of the work to date in Professor Grubbs' group utilizes homogeneous catalysts that are easy to control and are manipulated to produce well-defined polymeric structures. Although less common, heterogeneous catalysts are also used to provide new materials. In one case, the catalyst is covalently linked to a silica support in such a way that cyclic polymers are selectively produced. The heterogeneous system maintains the cyclic structure of the polymer throughout the reaction, and releases the cyclic polymer from the support, which provides a simple way to separate the product from the catalyst. The resulting high molecular weight hydrocarbon polymers provide model materials for verification of a variety of theoretical predictions. Additionally, large-scale synthesis of such material enables previously unrealized commercial applications. Another novel strategy uses a monomer which is introduced in the gas-phase to a heterogeneous system, which produces polymers with different properties than those formed in solution. This method provides hydrocarbon polymers which are not accessible using homogeneous catalysts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

聚合物在我们的日常生活中无处不在。它们是塑料、橡胶或凝胶，在生命系统中它们充当蛋白质的结构角色，也是 DNA 和 RNA 等遗传信息的来源。小化学单元（单体）连接在一起，产生具有任意数量所需功能的聚合物。聚合物的特性由单体以及单体单元的连接方式决定。加利福尼亚州帕萨迪纳市加州理工学院的格鲁布斯教授开发了生产聚合物的新方法，特别是开发具有复杂结构的新型聚合物，从而产生用于重要商业和学术用途的新材料。一种重要的方法涉及末端相连的非常长的聚合物链，使得所得环状聚合物没有起点或终点。这些聚合物的生产具有挑战性。许多理论表明，环状聚合物与末端未连接的相同聚合物具有不同的特性。预计这项工作将产生具有增强性能的聚合物。该项目为科学家的研究培训提供了一个优秀的平台，有助于为学术界和工业界培养一支熟练的劳动力队伍。开环复分解聚合（ROMP）是聚合物合成中的关键工具，用于生产众多模型系统，以及一些商业材料。迄今为止，格鲁布斯教授小组的大部分工作都利用均相催化剂，这些催化剂易于控制并可产生明确的聚合物结构。尽管不太常见，但多相催化剂也可用于提供新材料。在一种情况下，催化剂以选择性产生环状聚合物的方式共价连接至二氧化硅载体。该非均相体系在整个反应过程中保持了聚合物的环状结构，并将环状聚合物从载体上释放出来，这提供了一种将产物与催化剂分离的简单方法。由此产生的高分子量烃聚合物为验证各种理论预测提供了模型材料。此外，这种材料的大规模合成使得以前未实现的商业应用成为可能。另一种新颖的策略是使用一种单体，将其以气相引入非均相系统，产生的聚合物具有与溶液中形成的聚合物不同的性能。这种方法提供了使用均相催化剂无法获得的碳氢化合物。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。