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

在化学系的大分子，超分子和纳米化学项目的支持下，康奈尔大学的Erin Stache正在从商品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沿聚合物主链沿着引入可降解官能团。该聚合物链被设计为包含允许在光存在下链裂解的官能团，使得商品聚合物可光降解。研究小组还将研究所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广泛使用不可降解商品塑料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公众，使其了解回收行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。通过利用各种平台的社交媒体宣传，进一步将塑料知识普及到普通社会。该项目将重点开发异腈和乙烯基单体的可控聚合，将可降解功能安装到商品聚合物的主链中。在第一个目标中，钴介导的异腈和丙烯酸酯的自由基共聚反应的动力学和机理方面将进行系统的研究。重点将放在理解（a）活化的丙烯酸酯与异腈的交叉传播以形成亚氨酰基自由基和（B）亚氨酰基自由基在α-或β-断裂之前与丙烯酸酯的分子间加成，这可能导致链终止和/或转移。第二个目标将研究异腈/丙烯酸酯共聚物的性质，水解得到相应的聚（丙烯酸酯-共-酮），主链的细化，以及异腈和酮共聚物的降解行为。最后，将利用异腈在乙烯基单体的阳离子共聚中的两亲性来获得新的共聚物。异腈与乙烯基单体共聚反应机理的研究将有助于开发新的、更通用的可控自由基聚合方法。此外，本发明的目的是，这项研究有可能为一类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见解，这些百分比是在适当的暴露条件下允许光降解并保持所需的聚合物性能所必需的。该奖项反映了NSF的法定使命，并被认为值得通过利用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。

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.