Collaborative Research: Mechanochemistry of Metallocenes

有了这个奖项，化学系的大分子、超分子和纳米化学项目资助了南卡罗来纳州大学的唐传兵教授和斯蒂芬·L·杜克大学的克雷格开发了一类新的聚合物（塑料），对特定类型的压力作出反应。合成聚合物用途广泛，可加工，重量轻，并具有可调的机械性能，使其在日常生活中非常有用。这些由Tang集团制造的含金属聚合物用于制造对物理压力有反应但在高温下稳定的聚合物材料。 该团队的研究探索了机械化学控制塑料的设计和潜在用途。这种塑料可以通过物理操作而不是重新熔化来回收，最终在再利用过程中节省能源。 外联活动包括化学之星计划，提供研究资源，主要是在罗利达勒姆地区的本科院校。 经济上处于不利地位的学生和少数民族学生也通过南卡罗来纳州大学的美国化学学会项目种子夏季研究计划得到指导和接触尖端研究。 本项目的重点是开发合成方法，以主链含异戊二烯的聚合物和研究其机械化学反应性。 本研究计画利用开环复分解聚合法合成主链明确之茂金属聚合物及共聚物。 茂金属机械力化学的实验表征是通过聚合物声化学和单分子力谱的最新技术相结合进行的。 聚合物中的茂金属不稳定性进一步研究使用的计算模型，模拟在分子水平上施加的力。 进行机理研究，以阐明在分子尺度上剥离与剪切的相对贡献。 本工作的总体目标是了解高选择性机械化学断裂金属-氢键的机制和构效关系。这项工作有可能开发出机械响应和热稳定的合成聚合物，这两者对于大多数商品聚合物的可重复使用性和可回收性都很重要。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。

With this award, the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry is funding Professor Chuanbing Tang of the University of South Carolina and Professor Stephen L. Craig of Duke University to develop a new class of polymers (plastics) that respond to specific types of stress. Synthetic polymers are versatile, processable, light weight, and have tunable mechanical properties, making them useful in everyday life. These metal-containing polymers made by the Tang group are used to make polymer materials that respond to physical pressures but are stable at high temperatures. The team's research explores the design and potential uses of mechanochemically-controlled plastics. Such plastics may be recycled by physical manipulation rather than re-melting, ultimately resulting in energy-savings during reuse. Outreach activities include the Chem-STAR program that provides research resources to primarily undergraduate institutions in the Raleigh-Durham area. Economically disadvantaged and minority students are also mentored and exposed to cutting-edge research through American Chemical Society Project SEED summer research program at the University of South Carolina. This project is focused on developing synthetic approaches toward main-chain metallocene-containing polymers and studying their mechanochemical reactivity. The research plan utilizes ring-opening metathesis polymerization to synthesize well-defined main-chain metallocene polymers and copolymers. Experimental characterization of metallocene mechanochemistry is carried out through a combination of state-of-the-art techniques in polymer sonochemistry and single molecule force spectroscopy. Metallocene lability in polymers is further investigated using computational models that simulate forces applied at the molecular level. Mechanistic studies are conducted in order to elucidate the relative contribution of peeling versus shearing at the molecular scale. The overarching goal of this work is to understand the mechanisms and structure-activity relationship underlying the highly selective mechanochemical scission of metal-cyclopentadienyl bond. This work has the potential to develop synthetic polymers that are mechanically responsive and thermally stable, both of which are important for reusability and recyclability of most commodity 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.