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

在这个由NSF化学系管理的项目中，老道明大学的Trandon Bender教授和他的学生将进行研究，旨在了解基本的有机金属工艺，这些工艺允许高效合成聚合物，用于开发新产品，如食品储存、医疗器械和建筑材料的包装。将多个单体组合在一起的反应产生的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以形成稳定的络合物，限制了极性单体的掺入，降低了共聚速率。本德尔教授和他的学生将使用光催化剂和可见光打破稳定的螯合物，并允许共聚继续进行。他们还将研究如何在催化剂中添加路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杂量和更高催化共聚反应活性的新型乙烯共聚物。此外，该项目将培训来自老道明大学的不同群体的学生和诺福克州立大学的本科生。本德尔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-二亚胺聚合催化剂来裂解乙烯与极性单体如丙烯酸甲酯共聚时形成的稳定的络合物。这些螯合物阻碍了反应活性，导致了低极性单体的掺入。研究表明，光催化剂中的三重态-三重态能量转移到这些络合物上会产生以络合物为中心的三重态激发态，从而促进络合物的裂解，从而达到更好的包合和反应活性。通过对二亚胺配体骨架的修饰和光催化剂的变化，可以确定调节极性单体的掺入、支化和聚合物大小的最佳条件。此外，还将研究配体连接的Lewis酸，以了解近端的Lewis酸中心如何扰乱络合物的形成以及限制结合和反应的其他有害的极性单体相互作用。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。

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.