Controlling Ionomer Morphologies

控制离聚物形态

• 批准号: 0235106
• 负责人: Karen Winey
• 金额: $ 30.9万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-11-01 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0235106&HistoricalAwards=false
• 关键词: Controlling; Ionomer; Morphologies

The proposed research will investigate the morphology of ion-containing polymers, in particular ionomers, using model materials and a variety of analytical electron microscopy (AEM) methods. Ionomers are random copolymers with a majority of non-polar monomeric units and a minority (~5-10 mol%) of polar monomeric units, typically acids such as -COOH. The acid groups can be neutralized with cations to create ionic species such as -COO-Na+ in the case of a Na-neutralized carboxylic acid. Because these ionic species are considerably more polar that the surrounding matrix, there is a driving force for the ionic species to microphase separate and form ionic aggregates although the resulting morphologies of ionic aggregates are not well understood. Controlling the morphologies of ionomers is the primary goal of the proposed research and the first step to developing both a predictive theoretical model of these materials and a robust understanding of their structure-property relationships. These ionic aggregates act as physical crosslinks to toughen the polymer and lead to both current industrial applications (chemically resistant thermoplastics, tough coatings, permselective membranes for fuel cells, and food packaging materials) and a variety of potential technological applications (e.g. protection against chemical warfare). These complex polymeric materials spur scientific interest, because (1) these amphiphilic materials have ionic interactions that mimic biological macromolecules, (2) ionomers are readily available with a wealth of chemistries that includes amorphous and semicrystalline polymers and a range of cations, and (3) high-resolution analytical tools are now available to investigate the interdependencies of chemistry, processing, morphology and properties. Winey's scanning transmission electron microscopy (STEM) studies of ionomers since 1998 provide a valuable foundation to the proposed research in which Winey endeavors to identify the materials parameters and processing conditions that have the most substantial influence on the ionomer morphologies. The proposed work seeks to uncover reliable trends in the ionomer morphology in order to provide fundamental understanding of these complex materials. As Winey determines how the various materials and processing parameters influence the ionomer morphology they will be able to control the ionomer morphology. Two hallmarks of the proposed experimental plan are (1) the use of model materials, that is materials designed to address specific scientific questions, and (2) the use of multiple characterization tools including SAXS, FT-IR, and, in particular, a range of analytical electron microscopy (AEM) methods. Industrial, academic and military scientists have scientific interest in both the proposed research about ion-containing polymers and the development of AEM characterization tools for polymers. Winey will collaborate with the Lehigh Microscopy School to ensure that electron microscopists take full advantage of the AEM methods that are used within the proposed work to investigate complex, chemically heterogeneous polymeric materials. In addition, Winey will continue to both serve as a faculty co-advisor to the Society of Women Engineers on Penn's campus and hold an annual panel about opportunities for graduate studies and academic careers in engineering.

拟议的研究将使用模型材料和各种分析电子显微镜（AEM）方法研究含离子聚合物（特别是离聚物）的形态。 离聚物是无规共聚物，其中大部分是非极性单体单元和少数（~5-10 mol%）极性单体单元，通常是酸，例如-COOH。 酸基团可以用阳离子中和以产生离子物质，例如在Na中和的羧酸的情况下为-COO-Na+。 由于这些离子物质的极性比周围基质的极性大得多，因此存在使离子物质发生微相分离并形成离子聚集体的驱动力，尽管所产生的离子聚集体的形态尚不清楚。 控制离聚物的形态是本研究的主要目标，也是开发这些材料的预测理论模型和对其结构-性能关系有深入了解的第一步。 这些离子聚集体充当物理交联，使聚合物增韧，并导致当前的工业应用（耐化学性热塑性塑料、坚韧涂层、燃料电池的选择性渗透膜和食品包装材料）和各种潜在的技术应用（例如防化学战）。 这些复杂的聚合物材料激发了科学兴趣，因为（1）这些两亲性材料具有模拟生物大分子的离子相互作用，（2）离聚物很容易通过丰富的化学物质获得，包括无定形和半结晶聚合物以及一系列阳离子，以及（3）现在可以使用高分辨率分析工具来研究化学，加工，形态和化学之间的相互依赖性。 特性。 Winey 自 1998 年以来对离聚物的扫描透射电子显微镜 (STEM) 研究为拟议的研究提供了宝贵的基础，其中 Winey 致力于确定对离聚物形态影响最大的材料参数和加工条件。 拟议的工作旨在揭示离聚物形态的可靠趋势，以便提供对这些复杂材料的基本了解。 当 Winey 确定各种材料和加工参数如何影响离聚物形态时，他们将能够控制离聚物形态。 拟议实验计划的两个特点是（1）使用模型材料，即为解决特定科学问题而设计的材料，以及（2）使用多种表征工具，包括 SAXS、FT-IR，特别是一系列分析电子显微镜 (AEM) 方法。 工业、学术和军事科学家对含离子聚合物的拟议研究和聚合物 AEM 表征工具的开发都抱有科学兴趣。 Winey 将与 Lehigh 显微镜学院合作，确保电子显微镜学家充分利用拟议工作中使用的 AEM 方法来研究复杂的化学异质聚合物材料。 此外，怀尼将继续担任宾夕法尼亚大学校园女工程师协会的联合顾问，并每年举办一次关于工程学研究生学习和学术职业机会的小组讨论。