LEAPS-MPS: New Approaches to Achieve Ethylene and Polar Monomer Copolymerization

在这个由NSF化学部管理的项目中，Old自治领大学的Trandon Bender教授和他的学生将进行旨在了解基本有机金属过程的研究，这些过程允许有效合成用于开发新产品的聚合物，如食品储存包装，医疗器械和建筑材料。结合多种单体的反应导致塑料具有与含有单一单体的塑料不同的特性。然而，乙烯与极性共聚单体聚合可形成稳定的螯合物，限制极性单体的掺入并降低共聚速率。本德教授和他的学生将使用光催化剂和可见光来打破稳定的螯合物，并允许共聚继续进行。他们还将研究如何在催化剂中加入刘易斯酸来破坏这些螯合物的形成。他们的研究可能导致合成具有不同极性单体掺入和更高催化共聚反应性的新型乙烯共聚物。此外，本项目还将培养来自Old自治领大学（Old Dominion University）沿着的多元化学生，以及来自诺福克州立大学（Norfolk State University）的本科生。Bender教授和他的学生将研究能量转移和催化的结合，使用Pd-和Ni-二亚胺聚合催化剂裂解乙烯与丙烯酸甲酯等极性单体共聚时形成的稳定螯合物。这些螯合物阻碍反应性并导致低极性单体掺入。有人提出，从光催化剂到这些螯合物的三重态-三重态能量转移将产生以螯合物为中心的三重态激发态，其将促进螯合物的裂解以实现更好的掺入和反应性。通过二亚胺配体骨架的改性和光催化剂的变化，可以确定调节极性单体掺入、支化和聚合物尺寸的最佳条件。此外，还将对配体束缚的刘易斯酸进行研究，以了解近端刘易斯酸中心如何破坏螯合物的形成沿着其他限制掺入和反应性的有害极性单体相互作用。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。

In this project managed by the Chemistry Division at NSF, Professor Trandon Bender and his students at Old Dominion University will perform studies that aim to understand fundamental organometallic processes that allow for the efficient synthesis of polymers used for developing new products like the packaging for food storage, medical devices, and building materials. Reactions combining multiple monomers result in plastics with different characteristics than those containing a single monomer. However, polymerizing ethylene with polar comonomers can form a stable chelate, limiting the incorporation of the polar monomers and decreasing the copolymerization rate. Professor Bender and his students will use a photocatalyst and visible light to break open the stable chelates and allow copolymerization to continue. They will also investigate how adding a Lewis acid to the catalyst can be used to disrupt the formation of these chelates. Their studies could lead to the synthesis of new copolymers of ethylene with varied incorporation of polar monomers and higher catalytic copolymerization reactivity. Moreover, this project will train a diverse group student from Old Dominion University along with undergraduates from Norfolk State University.Professor Bender and his students will study the combination of energy transfer and catalysis using Pd- and Ni-diimine polymerization catalysts to cleave stable chelates that are formed during the copolymerization of ethylene with polar monomers such as methyl acrylate. These chelates hinder reactivity and result in low polar monomer incorporation. It is proposed that triplet-triplet energy transfer from a photocatalyst to these chelates will produce a chelate-centered triplet excited state that will promote cleavage of the chelate to achieve better incorporation and reactivity. Through modification of the diimine ligand backbones and variation of the photocatalysts, optimal conditions can be determined to modulate polar monomer incorporation, branching, and polymer size. Moreover, a ligand-tethered Lewis acid will be studied to understand how a proximal Lewis acidic center may disrupt chelate formation along with other detrimental polar monomer interactions that limit incorporation and reactivity.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.