Palladium(II) alpha-diimine catalysts for the living and block copolymerization of ethylene and alpha-olefins

Nickel and palladium α-diimine catalysts have both been developed for the polymerization of ethylene and α-olefins. The nickel α-diimines have high activities, can polymerize α-olefins in a living manner, and produce polyethylene with a branching number that varies with ethylene pressure. The palladium α-diimines can copolymerize ethylene with functionalized monomers such as acrylates, have been used to thoroughly study the mechanism of polymerization, and produce polyethylene with invariant branching number, but varying morphology with ethylene pressure. This dissertation describes the adaptation of the palladium α-diimines for polymerization of both ethylene and α-olefins under living conditions.; Chapter 2 describes the effects of solvent, quenching method, temperature, pressure, and catalyst diimine ligands on ethylene polymerizations. Chapter 3 describes the use of the conditions for living polymerization of ethylene to produce chain straightened polypropylene, poly(1-hexene), and poly(1-octadecene) in a living manner. The catalyst adduct is very influential in the polymerization of these α-olefins. The poly(1-hexene) systems are examined for the effect of catalyst and monomer concentrations as well as other trapping ligands on the polymerization process. The issue of isomerization of the α-olefin monomer by palladium is also addressed.; Chapters 4 and 5 describe some of the practical applications of living polymerization using the palladium α-diimines: block copolymerization and polymer end-capping. Chapter 4 presents the synthesis of block copolymers of (ethylene and 1-hexene) and (ethylene and 1-octadecene). The order in which the blocks are synthesized is important to the type of block copolymer (linear or core-shell) that is synthesized. Efforts to place a blocking group in the polymer chain in between the two blocks of the copolymer are also described. Finally, in Chapter 5, attempts to end-cap polyethylene at both the initial end and terminal end of the polymer chain are outlined. Success in initial end-capping with a methyl alkylacrylate functionality led to production of a macromonomer used in ATRP graft copolymerization with n-butyl acrylate.