CAREER: X-ray Absorption Spectroscopy of Thermal Behavior in Polymers

EPSCoR共同资助的CAREER奖将主要使用x射线吸收光谱（XAS）来检查玻璃化转变的动力学和结构响应。玻璃化转变是高分子材料中重要的现象之一。玻璃化转变中发生的基本微观结构变化还没有被很好地理解，也许更重要的是，Tg在每种聚合物的特定温度下发生的根本原因还没有被理解。其他技术，包括核磁共振波谱和中子散射，表明局部结构和动态变化发生在玻璃化转变。XAS将用于获得定量和精确的结构信息。初步数据表明，XAS可以用于检测玻璃化转变的局部变化。本提案描述了一个广泛的实验范围，该实验将检查在局部水平上发生的重要变化，因为聚合物通过其玻璃化转变。这些实验将能够评估林德曼式的玻璃化转变方法，这是一种由其他人提出并在本提案中探索的方法。这个项目的教育部分将涉及少数民族工程计划（MEP）。俄克拉荷马大学（University of Oklahoma）有近500名本科生是欧洲议会的成员，该委员会仅限于历史上代表性不足的黑人、西班牙裔和美洲印第安少数民族。教师和学生之间的一对一互动是招聘和留住这些学生的关键之一。PI与MEP项目的联系包括从招聘过程到毕业的本科经历的各个方面。它将包括前往主要是少数民族的高中，并进行旨在帮助招聘过程的讲座。＊＊＊

9733068 Grady This EPSCoR co-funded CAREER award will use primarily X-ray absorption spectroscopy (XAS) to examine responses in dynamics and structure at the glass transition. The glass transition is one of the most important phenomena in polymeric materials. The fundamental microscopic structural changes that occur with the glass transition are not well understood, and perhaps even more importantly, the fundamental reason that Tg occurs at the specific temperature it does for each polymer is not understood. Other techniques, including NMR spectroscopy and neutron scattering, show that local structural and dynamic changes occur at the glass transition. XAS will be used to obtain quantitative and precise structural information. Preliminary data show that XAS can be used to examine local changes at the glass transition. This proposal describes a broad range of experimentation which will examine the important changes occurring at the local level as a polymer progresses through its glass transition. These experiments will enable an evaluation of a Lindemann-type approach to the glass transition, an approach suggested by others and explored in this proposal. %%% The educational component of this project will involve the Minority Engineering Program (MEP). Almost 500 undergraduates at the University of Oklahoma are members of the MEP, which is limited to the historically underrepresented Black, Hispanic and American Indian ethnic minorities. One-on-one interactions between faculty and students are one of the keys to recruiting and retaining these students. The PI's association with the MEP program includes all facets of the undergraduate experience, from the recruiting process to graduation. It will involve travel to primarily minority high schools and talks designed to help with the recruiting process. ***