CAREER: CAS: Copolymerization of Vinyl Monomers with Isocyanides for Degradable Polymers

在化学系大分子、超分子和纳米化学项目的支持下，康奈尔大学的Erin Stache正在从单体开发可降解聚合物，单体是商品塑料中常见的构建块。聚合工艺的设计将包括沿着主要聚合物主干的可降解官能团。这种聚合物链的设计包含了允许在光存在下裂解链的功能，从而使商品聚合物可光降解。研究小组还将研究开发的聚合反应的机理和动力学特征，以进一步了解和优化反应条件，并扩大可用于这些过程的单体类型。从可持续发展的角度来看，与该项目相关的设计原则有可能为与广泛使用不可降解商品塑料有关的当前挑战提供一个有希望和可行的解决方案。教育和外展活动将侧重于教育不同年龄人口的公众关于回收工业的性质以及聚合物及其结构背后的科学。此外，还将举办培训讲习班，鼓励公众在其家庭和社区中产生影响。通过使用各种平台的社交媒体推广，进一步将塑料知识带入普通社会的努力将得到加强。该项目将专注于开发异氰酸酯和乙烯基单体的受控聚合，以将可降解功能安装到商品聚合物的主干中。在第一个目标中，我们将系统地研究钴引发的异氰酸酯和丙烯酸酯自由基共聚合的动力学和机理。将着重了解(A)活化的丙烯酸酯与异氰酸酯交叉繁殖以形成亚胺基自由基，以及(B)亚胺基基在α-或β-断裂之前与丙烯酸酯的分子间加成，这可能导致链的终止和/或转移。第二个目标是研究异氰酸酯/丙烯酸酯共聚物的性质、制备相应的聚(丙烯酸酯-共酮)的水解、主链的精制以及异氰酸酯和酮共聚物的降解行为。最后，将利用异氰酸酯在乙烯基单体的阳离子共聚中的双亲性质来获得新的共聚物。研究异氰酸酯与乙烯基单体共聚的机理可以开发出一种新的、用途更广的可控自由基聚合方法。此外，这项研究有可能为一种新型的可降解聚合物提供一条简便的途径，并为亚胺或酮官能团的掺入百分比提供重要的洞察，以便在适当暴露时允许光降解，同时又以其他方式保持理想的聚合物性能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular, and Nanochemistry program in the Division of Chemistry, Erin Stache of Cornell University is developing degradable polymers from monomers that are building blocks commonly found in commodity plastics. Polymerization processes will be designed to incorporate degradable functionality along the main polymer backbone. This polymer chain is designed to incorporate functionalities that allow for chain cleavage in the presence of light, rendering the commodity polymers photodegradable. The research team will also investigate the mechanistic and kinetic features of the developed polymerizations to understand further and optimize the reaction conditions and expand the monomer types that can be used in these processes. From the sustainability point of view, the design principles associated with this project have the potential to provide a promising and viable solution to the current challenges related to the widespread usage of non-degradable commodity plastics. The education and outreach activities will focus on educating the public across age demographics on the nature of the recycling industry and the science behind polymers and their structure. Additionally, training workshops will be developed to encourage the public to make an impact in their household and community. The efforts to further bring plastics knowledge prowess to general society will be enhanced through social media outreach using various platforms.This project will focus on developing controlled polymerization of isocyanides and vinyl monomers to install degradable functionality into the backbone of commodity polymers. In the first objective, kinetic and mechanistic aspects of cobalt-mediated radical copolymerization of isocyanides and acrylates will be systematically investigated. Strong emphasis will be placed on understanding (a) cross-propagation of activated acrylates with isocyanides to form imidoyl radicals and (b) intermolecular addition of the imidoyl radical to acrylates prior to alpha- or beta-scission that could result in the chain termination and/or transfer. The second objective will study the properties of isocyanide/acrylate copolymers, hydrolysis to afford the corresponding poly(acrylates-co-ketones), backbone elaboration, and degradation behavior of isocyanide and ketone copolymers. Lastly, the ambiphilic nature of isocyanides in a cationic copolymerization of vinyl monomers to access new copolymers will be exploited. Investigation of the mechanistic aspects of copolymerization of isocyanides with vinyl monomers could lead to a development of new and more versatile controlled radical polymerization methods. Additionally, this research has the potential to offer a facile route to a novel class of degradable polymers and to provide important insight into the percentage of imine or ketone functionality incorporation needed to both allow for photodegradation upon appropriate exposure and yet otherwise maintain desirable polymer properties.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.