Accessing Model, Functional Polyolefins and Polyolefin Copolymers with Ring-Opening Metathesis Polymerization

Abstract

Polyolefins are the most widely used commercial polymer available due to their low cost and excellent properties. Functionalized polyolefins with polar functional groups are desirable targets for more complex materials benefiting from the excellent properties of polyolefins, but these materials are challenging to synthesize using traditional polymerization methods. Ring-opening metathesis polymerization (ROMP) is a useful tool for achieving this goal as the catalysts are often tolerant to a wide range of functional groups, and the polymerizations are typically well-controlled making polymers with moderate dispersities. Chapter 2 describes the synthesis of epoxy-telechelic polyalkenamers and polyolefins made by ROMP of a cyclooctene-based monomer with difunctional chain-transfer agents. These polymers can then be rapidly photocured into model elastomers with few dangling-end defects and tunable properties based on the degree of saturation and the prepolymer molar mass. Appendix A shows the synthesis of similar elastomers made from polymers containing epoxide groups along the backbone of the polymer chain to explore the contributions of dangling-end defects to the mechanical properties of the final material. Chapters 3 and 4 describe the synthesis of a gas barrier polymer, an ethylene vinyl alcohol (EVOH) copolymer, made by ROMP of 3-functional cyclooctene. Chapter 3 explores the effect of regioregularity, given by ROMP of cyclooctenes with substituents in the 3 position, on the barrier properties of EVOH with the goal of decreasing the oxygen permeability of EVOH with high ethylene content while maintaining low water permeability. Chapter 4 discusses the additional effects of stereoregularity on the properties of a similar EVOH polymer. Appendix B describes the attempted synthesis of a disubstituted ROMP monomer for the synthesis of EVOH copolymers containing a higher vinyl alcohol copolymer content compared to the polymers made in Chapters 3 and 4. Finally, Appendix C presents the compilation and discussion of data from learning experience reports, an anonymous accident reporting system from the joint safety team.