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

Oklahoma State University, Stillwater OK

Investigators

Abstract

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.