FRG: GOALI: Collaborative Research: The Role of Polymer Molecular Architecture in Controlling Morphology in Quiescent and Flow-Induced Crystallization

FRG：GOALI：协作研究：聚合物分子结构在控制静态和流动诱导结晶形态中的作用

• 批准号: 0706578
• 负责人: Geoffrey Coates
• 金额: $ 32万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-15 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706578&HistoricalAwards=false
• 关键词: FRG; GOALI; Collaborative; Research; Role

This proposal unites academic research groups at the University of Virginia, Cornell University, and Florida State University with a leading polyolefin industrial scientist at ExxonMobil Research and Engineering Corporation. The research focuses on the development of novel polypropylene synthetic chemistry and an exploration of the fundamental physical phenomena underlying nucleation and growth in quiescent and flow-induced crystallization of semicrystalline polymers. Specifically, the PIs will use branching architecture as a tool to control nucleation and thereby manipulate the final crystalline morphology and macroscopic material properties.The team assembled to achieve this goal is skilled in novel polyolefin synthesis, crystallization kinetics and structural characterization, rheology and flow-induced crystallization, and industrial polymer processing. Model isotactic polypropylene (iPP) materials, including narrow molecular weight distribution linear, star, H-, and comb polymers, will be synthesized with precisely controlled stereoregularity and location of branch points. Quiescent crystallization experiments will principally seek to ascertain: (1) the influence of increasing chain irregularity due to branching on the level of crystalline organization and relative content of the alpha and gamma phases in homopolymer samples; and (2) the type and conformation of branching architecture that enhances nucleation in blends with linear chains.Flow-induced crystallization of linear and branched iPP blends will seek to determine: (1) how crystallization kinetics, nucleation density, degree of crystallinity, and crystalline structure are influenced by branching for fixed longest relaxation time; (2) if molecular architecture alters the local segmental orientation to promote nucleation; and (3) how polymorphism and morphology depend upon the number of arms (stars), ratio of branch to main chain molecular weight (H-polymers), and number of branch points (combs). NON-TECHNICAL SUMMARYOver 43 million tons of thermoplastic resins are produced in the U.S. each year with an estimated market value of over $65 billion. Much processing is performed in an ad hoc manner without the benefit of modeling or coherent blending strategies. Since the raw materials are often not renewable, waste in processing has a significant environmental impact. Moreover, the ability to exert better control over crystallinity and crystalline morphology will lead to better films, lighter weight parts, and also inject inexpensive PP materials into novel applications due to extended material properties. By providing quiescent and flow-induced crystallization data on well-defined material systems, theoretical tools allowing quantitative predictions of semicrystalline morphology are expected to result from this work. Students in Chemistry and Chemical Engineering will be not only be exposed to modern polymer synthesis and characterization, rheology, and material characterization techniques (e.g., X-ray scattering, birefringence, optical and transmission electron microscopy), but they will also be able to participate in industrial research experiences at ExxonMobil. The PIs will also combine their diverse talents and perspectives to assemble a K12 educational program on "Plastics" to be adopted in their respective communities. The PIs also have a record of including underrepresented groups in their research efforts (e.g., undergraduates from Ghana and Panama and several female undergraduates, graduates, and postdocs). Additionally, the FAMU-FSU College of Engineering is a jointly managed program of FAMU, a historically black college and university, and FSU with 40% minority and 25% female enrollment, and numerous African-American undergraduates have conducted undergraduate research in the laboratory of the PI at that institution.

该建议将弗吉尼亚大学，康奈尔大学和佛罗里达州立大学的学术研究小组与埃克森美孚研究与工程公司的一位领先的聚苯乙烯工业科学家。 该研究的重点是新型聚丙烯合成化学的发展以及对静态和流动诱导的半晶体聚合物结晶的基本物理现象的探索。 具体而言，PI将使用分支结构作为控制成核的工具，从而操纵最终的结晶形态和宏观材料的特性。为实现这一目标而组装的团队熟练于新型聚烯烃的综合，结晶动力学和结构性特征和结构性特征，流变学和流动诱导的结晶性和工业性和工业性处理。 模型的同型聚丙烯（IPP）材料，包括狭窄的分子量分布线性，星，H-和梳子聚合物，将通过精确控制的立体质量和分支点的位置合成。 静态结晶实验将主要寻求确定：（1）由于分支对均聚物样品中链条组织水平以及α和伽马相的相对含量而增加的链不规则性的影响； （2）分支结构的类型和构象可以增强与线性链的混合物中的成核。流量诱导的线性和分支IPP混合物的结晶将寻求确定：（1）结晶动力学，成核，成核，结晶度和结构结构如何影响固定长期的固定时间固定时间； （2）如果分子结构改变了局部分段取向以促进成核； （3）多态性和形态如何取决于臂的数量（恒星），分支与主链分子量（H聚合物）的比率以及分支点的数量（梳）。 非技术性摘要每年在美国生产4,300万吨热塑性树脂，估计市场价值超过650亿美元。 在没有建模或连贯的融合策略的好处，以临时的方式进行了许多处理。 由于原材料通常无法续签，因此处理中的废物具有重大的环境影响。 此外，由于扩展的材料特性，对结晶度和结晶形态更好地控制的能力将导致更好的薄膜，更轻的重量零件以及将廉价的PP材料注入新的应用中。 通过在定义明确的材料系统上提供静止和流动诱导的结晶数据，可以预期这项工作可以导致对半稳定形态进行定量预测的理论工具。 化学和化学工程学的学生不仅将暴露于现代聚合物合成和表征，流变学和物质表征技术（例如X射线散射，双重散射，光学和传输电子显微镜），而且还将能够参与埃克森美孚的工业研究经验。 PI还将结合其多样化的才能和观点，以组建有关在各自社区中采用的“塑料”的K12教育计划。 PI在研究工作中还记录了将代表性不足的群体包括在内（例如，来自加纳和巴拿马的本科生以及几位女性本科生，毕业生和博士后）。 此外，FAMU-FSU工程学院是一项由历史悠久的黑人学院和大学共同管理的FAMU计划，其中有40％的少数族裔和25％的女性入学率，并且该机构的PI实验室在PI实验室进行了本科研究。