CAS: Dithioacetal as a Highly Tunable and Versatile Bond for the Design of Chemically Recyclable and Dynamic Covalent Polymers

CAS：二硫缩醛作为高度可调和多功能的键，用于化学可回收和动态共价聚合物的设计

• 批准号: 2305045
• 负责人: Ying Yang
• 金额: $ 45.16万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305045&HistoricalAwards=false
• 关键词: CAS; Dithioacetal; Highly; Tunable; Versatile

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Ying Yang of the University of Nevada at Reno is using ring-opening and -closing polymerization strategies to prepare recyclable polydithioacetals. Polydithioacetals are long chain macromolecules in which the main polymer backbone contains chemical element sulfur in addition to carbon commonly seen in commodity plastics. This class of polymers is chemically stable and yet has highly modifiable backbones and side groups. As a result, polydithioacetals are promising candidates for recyclable polymers with tunable properties. Research associated with this project will develop an in-depth understanding of the polymerization mechanisms of dithioacetal polymerization, investigate how thermodynamics and kinetics of polymerization are affected by the rich structural variations, and explore using these chemistries to enable dynamic architectural transformations of thermoplastic and thermoset polydithioacetals controlled by stimuli. The results from these fundamental studies have the potential to lead to the development of novel recyclable polymers which can be reprocessed at high temperatures and depolymerized on-demand back into cyclic macrocycles. From the sustainability point of view, the design principle associated with this project provides a very promising and viable solution to the current challenges associated with the widespread usage of non-degradable vinyl plastics. Hence, the developed methodology could be utilized to build readily degradable and sustainable plastics that are amenable to a circular economy life cycle. The research team will be actively involved in disseminating the results via publications and presenting the work at conferences and local events. Furthermore, community outreach will be conducted by establishing close relationships with Hug High School which has a large Hispanic student population. The project will also facilitate the research and education of polymer science at the University of Nevada Reno by integrating polymer chemistry modules into the large general chemistry classes.This research will focus on studying polydithioacetals that are capable of reversible entropy-driven ring-opening polymerization (ED-ROP) and ring-closing depolymerization (RCD) as a versatile platform for the development of recyclable polymers, as well as dynamic covalent systems. The dynamics will be enabled by acid-catalyzed dithioacetal exchange reactions. Building on promising preliminary results, the project aims to develop a detailed understanding of the chemistry and thermodynamics of ED-ROP for dithioacetal macrocycles through three interconnected objectives: (1) understand the polymerization mechanism with different initiator/catalyst systems and obtain controlled “living” cationic polymerization, (2) vary the structures of polydithioacetal backbones and side groups/chains and study their effects on the monomer-polymer equilibrium, and (3) develop reprocessable and depolymerizable polydithioacetal thermosets with controlled degradation by light and mechanical force. These research activities have a strong sustainability component and the potential to generate fundamental chemistry knowledge of relevance to using ED-ROP for the development of inherently practical, recyclable and functional polymers.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.

在化学系中的大分子，超分子和纳米化学计划的支持下，内华达大学里诺大学的Ying Yang Ying Yang Ying Yang Ying Yang Ying Yang Ying Yang Ying Yang Ying Yang Ying Yang Yang Yang yang yang yang yang yang yang yang yang reno的Ying Yang Ying Yang Yang Yang Yang Yang Yang Yang Yang yang yang yang yang yang yang yang yang yang yang reno的Ying Yang正在使用开环和聚合策略来准备可回收可回收的多迪迪思太材料。聚二思齿是长链大分子，其中主要聚合物主链除了在商品塑料中常见的碳之外，还含有化学元素硫。这类聚合物在化学上是稳定的，但具有高度可修饰的骨干和侧面组。结果，多迪迪思齿是具有可调性特性的可回收聚合物的候选者。与该项目相关的研究将深入了解二硫乙乙化聚合的聚合机制，研究聚合的​​热力学和动力学如何受到丰富的结构变化的影响，并使用这些化学作用来探索这些化学作用以启用由stompoloset polydithiocactals对立的动态架构转化。这些基本研究的结果有可能导致新型可回收聚合物的发展，这些聚合物可以在高温下重新加工，并按需沉积回循环大环。从可持续性的角度来看，与该项目相关的设计原理为与不可降解的乙烯基塑料相关的当前挑战提供了一个非常有希望和可行的解决方案。因此，可以利用开发的方法来构建容易降解和可持续的塑料，这些塑料适合经济生命周期。研究团队将积极参与通过出版物来传播结果，并在会议和当地活动中介绍工作。此外，将通过与拥有大量西班牙裔学生人口的拥抱高中建立密切的关系来进行社区宣传。 The project will also facilitate the research and education of polymer science at the University of Nevada Reno by integrating polymer chemistry modules into the large general chemistry classes.This research will focus on studying polydithioacetals that are capable of reversible entropy-driven ring-opening polymerization (ED-ROP) and ring-closing deposition (RCD) as a versatile platform for the development of recyclable polymers, as well as动态共价系统。该动力学将通过酸催化的二硫乙乙化交换反应来启用。 Building on promised preliminary results, the project aims to develop a detailed understanding of the chemistry and thermodynamics of ED-ROP for dithioacetal macrocycles through three interconnected objectives: (1) Understand the polymerization mechanism with different initiator/catalyst systems and obtained controlled “living” cationic polymerization, (2) vary the structures of polydithioacetal backbones and side groups/chains and study它们对单体聚合物平衡的影响，（3）产生可通过光和机械力控制降解的可重新定位和可聚合的多迪迪乙乙乙乙乙化体。这些研究活动具有强大的可持续性组成部分，并具有与使用ED-ROP来开发固有的实用，可回收和功能性聚合物的基本化学知识的潜力。该奖项反映了NSF的法定任务，并通过使用基金会的智力和更广泛的影响来审查Criteria来诚实地通过评估来诚实地支持。