GOALI: Using Tapered Copolymers to Understand Nanoscale Interfaces within Polymeric Materials and Their Influence on Macroscale Properties

非技术总结：为了满足汽车、医疗、电子和消费产品领域不断变化的需求，总是需要具有可控性能的新材料。例子包括更轻但更坚韧的材料，不含添加剂的材料，随着时间的推移可能会对健康或环境造成危害，或者成分简化但机械性能优越的材料。杰弗里·怀特教授和他的研究小组与雪佛龙菲利普斯化学公司合作，试图发现如何控制有用的新聚合物材料的产生，这些材料由非常简单的成分制成，即使材料的化学成分保持固定，其最终性能也可以定制以适应广泛的应用。这些新型聚合物材料被称为锥形共聚物，大分子结构中单个化学成分的空间排列有可能通过创造独特的纳米长度尺度的界面来赋予可变但可控的物理特性。通过选择使用哪两种聚合物起始材料来制造分子及其在分子结构中的排列顺序，可以获得不同的最终物理性质，包括软与硬、低温与高温稳定性、韧与脆。由于俄克拉何马州大学和工业科学家之间的这种合作的特殊方面，来自各个层次的学生将有机会参与研究，并观察学术和工业环境中科学技术实践的差异。此外，拟议的制造新材料的方案可能适合于消除在早期材料中造成问题的有毒添加剂的必要添加，从而为医疗应用创造新的机会。技术概述：可控活性聚合技术的最新进展导致了许多新聚合物材料的设计。由这些进展提供的新材料的一个令人兴奋的子集包括共聚物，其共聚单体的顺序在单个链的长度上以某种系统的方式变化。一种称为锥形共聚物合成的方法为共聚物的界面形态控制提供了重要的希望。在之前的一个项目中，PI证明了锥形共聚物中不同的界面类型会显著影响苯乙烯-丁二烯共聚物的分子和某些物理性质，即使共聚物的组成基本保持不变。利用在表征复杂非晶聚合物体系的广泛历史中开发的实验方法，PI将与GOALI合作伙伴雪佛龙菲利普斯公司的共同PI Joe Zhou博士合作，研究在锥形共聚物中创建受控纳米级界面的程度，以及这些界面对最终宏观性能的影响。co-PI将使用中试规模的阴离子聚合反应器制备广泛的锥形和反锥形共聚物材料，这提高了通过该计划得出的结论对大规模材料合成和应用具有实际意义的可能性。PI在使用先进表征方法理解复杂大分子共混物和复合材料方面的专业知识将用于在梯度和锥形共聚物领域开发广泛适用的结构/合成/性能关系，其影响应远远超出丁苯共聚物。

NON-TECHNICAL SUMMARY:New materials with controllable properties are always needed to meet constantly-evolving requirements in the automobile, medical, electronics, and consumer products areas. Examples include lighter but tougher materials, materials free from additives that can cause health or environmental hazards over time, or materials with simplified compositions but superior mechanical performance. Professor Jeffery White and his research group, in collaboration with Chevron Phillips Chemical Company, seek to discover how to control the creation of useful new polymeric materials, made from very simple components, with final properties that can be tailored to fit a wide range of applications even when the chemical composition of the material remains fixed. These new types of polymer materials are called tapered copolymers, and the spatial arrangement of the individual chemical components within the large molecule structure has the potential to impart variable, but controllable, physical properties through the creation of unique nanometer length-scale interfaces. By choosing which two types of polymer starting materials are used to make the molecule and their order of arrangement within the molecular structure, different final physical properties can be achieved, including soft versus hard, low versus high temperature stability, and tough versus brittle. Due to the special aspects of this collaboration between university and industrial scientists within the State of Oklahoma, students from all levels will have the opportunity to participate in research, and observe differences in the practice of science and technology in academic and industrial environments. Further, the proposed schemes for making new materials may be suitable for eliminating the necessary addition of toxic additives that have caused problems in earlier materials, thus creating new opportunities for use in medical applications.TECHNICAL SUMMARY:Recent advances in controlled living polymerization techniques have led to the design of many new polymeric materials. An exciting subset of the new materials afforded by these advances includes copolymers whose comonomer ordering varies in some systematic manner across the length of individual chains. One method, called tapered copolymer synthesis, offers significant promise for interfacial morphology control in copolymers. In a previous project, the PI demonstrated that different interfacial types in tapered copolymers significantly impacted molecular and some physical properties in styrene-butadiene copolymers, even when the comonomer composition was essentially held fixed. Using the experimental approaches developed during an extensive history of characterizing complex amorphous polymer systems, the PI in collaboration with the GOALI partner co-PI Dr. Joe Zhou of Chevron Phillips, will investigate the degree to which controlled nanoscale interfaces can be created in tapered copolymers, and the impact of those interfaces on final macroscopic properties. An extensive array of tapered and inverse-tapered copolymer materials will be prepared by the co-PI using a pilot-scale anionic polymerization reactor, which enhances the probability that the conclusions reached through the program can have practical implications for large-scale materials synthesis and applications. The PI's expertise in understanding complex macromolecular blends and composites using advanced characterization methods will be used to develop widely-applicable structure/synthesis/property relationships in the area of gradient and tapered copolymers, the impact of which should extend far beyond styrene-butadiene copolymers.