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正在从普通塑料中常见的单体中开发可降解聚合物。聚合过程将被设计成包含沿主聚合物骨架的可降解功能。这种聚合物链被设计成允许在光的存在下链分裂的功能，使商品聚合物可光降解。研究小组还将研究已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当前与不可降解商品塑料的广泛使用相关的挑战提供一个有前途和可行的解决方案。教育和推广活动将侧重于教育不同年龄的公众，使他们了解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，鼓励公众对其家庭和社区产生影响。将通过使用各种平台的社交媒体外展，进一步努力将塑料知识能力带给普通社会。该项目将侧重于开发异氰化物和乙烯基单体的可控聚合，以将可降解功能安装到商品聚合物的骨架中。在第一个目标中，将系统地研究钴介导的异氰酸酯和丙烯酸酯自由基共聚的动力学和机理。重点将放在理解(a)活化的丙烯酸酯与异氰酸酯的交叉繁殖，形成酰基自由基和(b)在α -或β -断裂之前，酰基自由基在丙烯酸酯上的分子间加成，可能导致链终止和/或转移。第二个目标将研究异氰化物/丙烯酸酯共聚物的性质，水解得到相应的聚（丙烯酸酯-共酮），主链精化，以及异氰化物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阳离子共聚过程中的两亲性来获得新的共聚物。研究异氰酸酯与乙烯基单体共聚的机理有助于开发新的、更通用的可控自由基聚合方法。此外，这项研究有可能为新型可降解聚合物提供一条便捷的途径，并为亚胺或酮类功能结合所需的百分比提供重要见解，这些百分比既允许在适当暴露时进行光降解，又能保持理想的聚合物性能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.