Dynamic Multi-state Living Coordination Polymerization for Next Generation Polyolefins

下一代聚烯烃的动态多态活性配位聚合

• 批准号: 2247554
• 负责人: Lawrence Sita
• 金额: $ 57.5万
• 依托单位: University of Maryland, College Park
• 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: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247554&HistoricalAwards=false
• 关键词: Dynamic; Multi; state; Living; Coordination

With the support of the Chemical Catalysis (CAT) and the Macromolecular, Supramolecular, and Nanochemistry (MSN) Programs in the Division of Chemistry, Professor Lawrence Sita of the University of Maryland, College Park is developing new polymerization catalysts that can be programmed to deliver multiple products from a single initiator. This ‘one catalyst – many materials’ paradigm is being investigated to expand the range of new polyolefin materials that possess technologically-useful physical properties that are of benefit to society and the economy, such as recyclability and serving as replacements for less environmentally benign legacy plastics. Group 4 catalysts are being tuned to undergo selective polymerization in systems that would typically be assumed to be unselective. The activities that are being pursued also provide an excellent forum for training the next generation of scientists for science- and engineering-related careers in education, industry, and science policy, and importantly, those who are members of underrepresented groups.Homogeneous olefin polymerization catalysts are traditionally optimized to produce a single type of polymer from a single monomer. In contrast, Professor Sita and his research team are designing and preparing Group 4 d(0)-complexes supported by cyclopentadienyl and amidinate ligands that can serve as initiators for the living coordinative chain transfer polymerization of olefins into multiple new classes of polyolefin products. By exerting control over the relative rates of reversible dynamic reactions that are competitive with chain-growth propagation, highly versatile multi-state polymerization processes are being programmed to deliver a spectrum of different products from a single initiator under otherwise identical conditions. Different controlling elements of the system being explored include: the structure and chirality of the amidinate ligands, the effect of coordinative groups installed on the amidinate ligands, as well as reaction mixture temporal control over polymer composition. These studies are working towards the advance of polyolefin materials with desirable physical properties while establishing new elements of catalytic control in complex systems.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.

在化学催化(CAT)和化学系大分子、超分子和纳米化学(MSN)计划的支持下，马里兰大学园区分校的劳伦斯·西塔教授正在开发新的聚合催化剂，这种催化剂可以编程为从单一引发剂提供多种产品。目前正在研究这种“一种催化剂-多种材料”的范例，以扩大新型聚烯烃材料的范围，这些材料具有对社会和经济有益的技术有用的物理性能，例如可回收利用，并可用作对环境不那么友好的传统塑料的替代品。第4族催化剂正在进行调整，以便在通常被认为是非选择性的体系中进行选择性聚合。正在进行的活动也为培养下一代科学家提供了一个极好的论坛，这些科学家在教育、工业和科学政策方面从事与科学和工程相关的职业，而重要的是，那些属于代表性不足的群体的科学家。均相烯烃聚合催化剂传统上是优化的，以从单一单体生产单一类型的聚合物。相反，Sita教授和他的研究团队正在设计和制备由环戊二烯和酰胺配体支撑的第4族d(0)-络合物，这些络合物可以作为活性配位链转移聚合的引发剂，使烯烃聚合成多种新的聚烯烃产品。通过对与链生长繁殖竞争的可逆动态反应的相对速度进行控制，高度通用的多态聚合过程正在被编程，以在其他相同的条件下从单一引发剂提供不同产品的光谱。该体系的不同控制因素包括：酰胺化配体的结构和手性、酰胺化配体上配位基团的影响以及反应混合物对聚合物组成的时间控制。这些研究致力于发展具有良好物理性能的聚烯烃材料，同时在复杂系统中建立新的催化控制元素。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。