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

非技术概述：汽车、医疗、电子和消费品领域总是需要性能可控的新材料来满足不断变化的要求。例如，更轻但更坚韧的材料，不含可能随着时间的推移而导致健康或环境危害的添加剂的材料，或者成分简单但机械性能优异的材料。Jeffery White教授和他的研究小组与雪佛龙菲利普斯化工公司合作，试图发现如何控制有用的新型聚合物材料的创造，这些材料由非常简单的成分制成，即使在材料的化学成分保持不变的情况下，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建独特的纳米长度-尺度界面来赋予可变但可控的物理性能。通过选择使用哪两种类型的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能，包括软与硬、低温与高温稳定性以及韧性与脆性。由于俄克拉荷马州大学和工业科学家之间合作的特殊方面，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和技术实践的差异。此外，建议的制造新材料的方案可能适合于消除在早期材料中引起问题的有毒添加剂的必要添加，从而为在医疗应用中使用创造新的机会。技术概述：可控活性聚合技术的最新进展导致了许多新的聚合材料的设计。这些进展提供的新材料中一个令人兴奋的子集包括共聚物，其共聚单体的有序性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前景。在之前的一个项目中，PI表明，锥形共聚物中不同的界面类型对丁苯共聚物的分子和某些物理性质有显著影响，即使共聚单体组成基本上保持不变。利用在表征复杂无定形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、Chevron Phillips的Joe周博士合作，研究在锥形共聚物中可以创建可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。利用中试规模的阴离子聚合反应器，co-PI将制备一系列广泛的锥形和反锥形共聚材料，这增加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在使用先进的表征方法了解复杂的大分子混合物和复合材料方面的专业知识将被用来发展在梯度和锥形共聚物领域广泛适用的结构/合成/性能关系，其影响应该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.