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）和化学系的大分子，超分子和纳米化学（MSN）计划的支持下，马里兰州大学的Lawrence Sita教授正在开发新的聚合催化剂，该催化剂可以通过编程从单个引发剂中提供多种产品。这种“一种催化剂-多种材料”的范例正在研究中，以扩大新的聚烯烃材料的范围，这些材料具有对社会和经济有益的技术有用的物理特性，例如可回收性和作为环境友好性较差的传统塑料的替代品。第4类催化剂被调整为在通常被认为是非选择性的系统中进行选择性聚合。正在进行的活动也提供了一个很好的论坛，培训下一代科学家的科学和工程相关的职业教育，工业和科学政策，重要的是，那些谁是代表性不足的群体的成员。均相烯烃聚合催化剂传统上是优化的，从一个单一的单体生产一种类型的聚合物。相比之下，Sita教授和他的研究团队正在设计和制备由双胍基和脒基配体支持的第4族d（0）-络合物，这些络合物可以作为烯烃活性配位链转移聚合成多种新型聚烯烃产品的引发剂。通过对与链增长传播竞争的可逆动态反应的相对速率施加控制，高度通用的多状态聚合方法被编程为在其他相同的条件下从单一引发剂递送一系列不同的产物。 所探索的系统的不同控制元素包括：脒基配体的结构和手性，安装在脒基配体上的配位基团的影响，以及反应混合物对聚合物组合物的时间控制。这些研究致力于推进具有理想物理性能的聚烯烃材料的发展，同时在复杂系统中建立催化控制的新要素。该奖项反映了NSF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。