CAREER: Medium-Range Order in Polymeric Phosphate Glasses: Effects of Atomic-Scale Structures on Macroscopic Properties

这个学院早期职业发展项目将研究关于非晶材料性质的最基本和最普遍的问题之一：即无序材料的结构特征与用于生产非晶材料的各种物理过程之间的关系是什么。具体而言，该项目将研究由成分变化引起的聚合物磷酸盐玻璃结构的变化，并通过熔融加工演变。它将把这些结构变化与新型耐用聚合物磷酸盐玻璃的流变性、耐水性和抗结晶性联系起来。研究目标将采用跨学科的方法来完成，该方法整合了材料科学、流变学、固态化学和物理以及工艺工程等方面，以探索受控剪切流对所生产的玻璃的短程和中程有序结构的影响。宏观玻璃结构将通过各种光谱、显微镜、高效液相色谱和量热技术进行研究；然后通过x射线衍射实验将其与微观起源联系起来。这项工作将把熔融加工条件（如剪切变形、温度和剪切速率）与玻璃的最终流变行为联系起来。结果将与已报道的磷酸盐玻璃结构模型进行比较。该项目将发展成为爱荷华州立大学的主要教育和研究能力，并将通过与磷酸盐玻璃研究领域的国际领导者合作而得到促进。此外，材料科学与工程（MSE）系的学生将获得相关的、以实践为导向的教育，这对工业界很有吸引力。这一目标将通过以下方式实现：(a)为MSE的研究生和本科生提供研究经验；(b)向学生展示跨学科研究在利用创新的、以电脑为基础的教学模块解决基本问题方面的协同效应；(c)利用产业合作伙伴的人力和设备资源，发展研究生在业界实习的机会；(d)为高中理科学生编制简单实用的材料科学示范包和其他远程教育教学辅助工具；(e)发展学生合作学习小组，以及(f)将研究成果纳入首席研究员的课程。了解化学耐久性和抗结晶倾向对磷酸盐玻璃的组成和熔融加工条件的依赖关系，将增强磷酸盐玻璃在高膨胀金属应用的玻璃-金属密封、阻燃剂、生物材料、核废料储存材料、光学、磷光/荧光材料、闪烁体等应用中的应用。以及承重有机/无机复合材料。此外，爱荷华州立大学材料科学与工程（MSE）系的学生将获得相关的、以实践为导向的教育，这对工业界很有吸引力。＊＊＊

9733350 Otaigbe This Faculty Early Career Development project will investigate one of the most fundamental and general questions regarding the properties of amorphous materials: namely, what is the relationship between the structural characteristics of disordered materials and the various physical processes used to produce the amorphous material. Specifically, the project will examine the changes in polymeric phosphate glass structure caused by variations in composition and evolved by melt processing. It will correlate these structural changes in novel durable polymeric phosphate glasses with the rheology, durability to water, and resistance to crystallization. The research objectives will be accomplished using an interdisciplinary approach that integrates aspects of materials science, rheology, solid-state chemistry and physics, and process engineering to explore the effects of controlled shear flow on both the short-range and the intermediate-range order structure of the glasses produced. The macroscopic glass structure will be studied by various spectroscopy, microscopy, high performance liquid chromatography, and calorimetry techniques; it will then be linked to its microscopic origin through X-ray diffraction experiments. This work will correlate melt-processing conditions (such as shear distortion, temperature, and shear rate) with the ultimate rheological behavior of the glass. The results will be compared to reported structural models for phosphate glasses. This project will evolve into a major education and research capability at Iowa State University that will be facilitated through collaborations with international leaders in phosphate glass research. In addition, students in the Materials Science and Engineering (MSE) Department will be provided with a relevant, and practice-oriented education that is attractive to industry. This objective will be accomplished by (a) providing research experiences for graduate and undergraduate students in MSE; (b) demonstrating to students the synergistic effect of interdisciplinary research in solving fundamental problems using innovative, computer-based instructional modules; (c) developing graduate student internship opportunities with industry by leveraging both the human and the equipment resources of the industrial collaborators; (d) developing simple practical materials science demonstration kits for high school science students and other distant education teaching aids; (e) developing cooperative student learning groups, and (f) incorporating research findings into the principal investigator's courses. %%% Understanding the dependencies of chemical durability and resistance to crystallization tendencies on both the composition and the melt-processing conditions of phosphate glasses will enhance the use of phosphate glasses in applications such as glass-to-metal seals for high expansion metal applications, flame retardants, biomaterials, storage materials for nuclear wastes, optics, phosphorescent/fluorescent materials, scintillators, and load-bearing organic/inorganic composites. In addition, students in the Materials Science and Engineering (MSE) Department at Iowa State University will be provided with a relevant, and practice-oriented education that is attractive to industry. ***