Elucidating Ring Opening Metathesis Copolymerization Thermodynamics of Monomers with Dissimilar Ring Strain Energies

在化学系大分子、超分子和纳米化学项目的支持下，贾斯汀·G·佛罗里达州立大学的Kennemur正在研究开环易位聚合（ROMP）中环状单体的共聚热力学。 将两种或更多种单体共聚成一种大分子或聚合物提供了一种生产社会塑料的不同方法，这些塑料包含用于无数应用的分布式功能。具体地，ROMP通过使用公认的催化剂的应变环烯烃单体的链生长提供了多种工业相关的聚烯烃基材料。该Kennemur团队将进行系统的合成，动力学和机理研究，以了解基本热力学原理沿着关键条件（如催化剂和溶剂）如何最终决定各种环烯烃共聚单体的竞聚率及其在生长的大分子链中的排序。该项目还将引入新的基于生物质的萜烯环烯烃，以提供ROMP中常用的环烯烃单体所不能提供的中环应变的热力学谱。 该研究团队将继续与美国化学学会第一个高分子化学部和高分子材料科学与工程部的学生分会合作，该分会是佛罗里达农业和机械大学（FAMU）的历史黑人学院/大学和佛罗里达州立大学的R1研究型大学之间共同建立的。 本学生章将汇集高度多样化的学生和教师，旨在聚合物科学研究。 这个独特的平台将另外被用来促进研究生和本科生的成长，走向领导力的发展，无论是由外展和一个新的佛罗里达州的会议，以聚合物科学为中心的发展。这个项目将侧重于阐明开环易位共聚热力学的单体与不同的环应变能。在第一个目标中，低应变环戊烯单体的竞聚率是高度敏感的轻微变化，在他们的环应变能（RSE）将使用现代集成的方法来确定。 然后将确定的参数与聚合物微结构内的单体排序相关，作为热力学原理（单体浓度、化学计量和温度）的函数。 第二个目的将检查δ-蒎烯及其变体，异松油烯，其具有在ROMP中通常采用的高应变和低应变单体之间的RSE。基本的热力学研究和这些三元共聚物为基础的单体与对方和低/高RSE单体的共聚反应也将进行探讨。 最后，最后一个具体的目标将推动RSE之间的差距的限制，通过研究高应变和低应变单体的组合。这样的调查有可能交替和块状测序策略。总之，这些研究有可能提供指导原则的合理设计共聚物从容易获得的环烯烃单体;存在揭示将应用于开环聚合（ROMP）的基本原理的潜力，通常，因此，有一个重要的长期-该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Professor Justin G. Kennemur of Florida State University is studying copolymerization thermodynamics of cyclic monomers in ring opening metathesis polymerization (ROMP). Copolymerization of two or more individual monomers into one macromolecule or polymer offers a divergent means of producing societal plastics that contain distributed functionality for a myriad of applications. Specifically, ROMP affords a variety of industrially relevant polyolefin-based materials through chain growth of strained cycloolefin monomers using well-established catalysts. This Kennemur team will perform systematic synthetic, kinetic and mechanistic studies to gain understanding of how basic thermodynamic principles along with key conditions, such as catalyst and solvent, ultimately dictate the reactivity ratios of various cycloolefin comonomers and their sequencing within the macromolecular chains that are grown. The project will also introduce new biomass-based terpene cycloolefins to provide a thermodynamic spectrum of medium ring-strain not afforded by the commonly employed cycloolefin monomers in ROMP. The research team will continue engagement with the first ever American Chemical Society Division of Polymer Chemistry and Division of Polymer Materials Science and Engineering student chapter that is co-established between a historically black college/university of Florida Agricultural and Mechanical University (FAMU) and an R1 research university in Florida State University. This student chapter will bring together a highly diverse body of students and faculty aimed at polymer science research. This unique platform will additionally be utilized to promote the growth of graduate and undergraduate students towards the development of leadership, both governed by outreach and the development of a new Florida-based conference, centered on polymer science.This project will focus on elucidating ring opening metathesis copolymerization thermodynamics of monomers with dissimilar ring strain energies. In the first aim, reactivity ratios of low-strain cyclopentene monomers that are highly sensitive to slight variations in their ring strain energy (RSE) will be determined using modern integrated approaches. Determined parameters will then be correlated to monomer sequencing within the polymer microstructure as a function of thermodynamic principles (monomer concentration, stoichiometry, and temperature). The second aim will examine, delta-pinene, and its variant, apopinene , which have RSEs that are in-between the high strain and low strain monomers typically employed in ROMP. Fundamental thermodynamic investigations and copolymerizations of these terpene-based monomers with each other and with low/ high RSE monomers will also be explored. Finally, the last specific aim will push the limits of disparity between RSEs by investigating high strain and low strain monomers in combination. Such investigations have potential for both alternating and blocky sequencing strategies. Taken together, these studies have the potential to provide guiding principles for the rational design of copolymers from readily available cycloolefin monomers; there is the potential to uncover basic principles that will apply to ring-opening polymerization (ROMP), in general, and thereby have a significant long-term scientific impact on polymer chemistry.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.