Synthesis, characterization and properties of epoxide-containing block and alternating copolymers

The synthesis of epoxide containing block and alternating copolymers has been investigated in this research. Poly(ethylene oxide-2-ethyl-2-oxazoline) (PEO) copolymers have been synthesized with poly(ethylene oxide) macroinitiators ranging from 0.75K-40K. Monohydroxy functionalized PEO oligomers have been synthesized with potassium tert-butoxide as an initiator in tetrahydrofuran, and in the bulk. The PEO oligomers were reacted with 4-(chloromethyl) benzoyl chloride to yield a 4-(chloromethyl) benzoate functionalized PEO oligomer quantitatively. This oligomer was further reacted in the melt with sodium iodide to result in 4-(iodomethyl) benzoate functionalized PEO oligomers. The iodo adduct (macroinitiator) initiated the polymerization of 2-ethyl-2-oxazoline, the second block of the diblock copolymer. The formation of the poly(ethylene oxide-2-ethyl-2-oxazoline) copolymer resulted in materials ranging from 20-80 weight percent poly(2-ethyl-2-oxazoline) (PEOX). These materials were water soluble with PEOX as a strong hydrogen bonding block in the copolymer. The diblock copolymers may have potential uses in particle stabilization, and coating applications.; The synthesis of poly(ethylene oxide-b-2-ethyl-2-oxazoline) copolymers was accomplished in the melt. Melt polymerizations eliminate the use of solvents, and result in a more efficient synthesis of polymeric materials. The individual blocks of the diblock copolymer can be synthesized to a controlled molecular weight with narrow polydispersities due to the living anionic and cationic polymerization mechanisms for PEO and PEOX, respectively.; The diblock copolymers, poly(ethylene oxide-b-2-ethyl-2-oxazoline), were microphase separated with amorphous and crystalline domains. In the 0.75K-3K (PEO-b-PEOX) copolymer, the PEO crystalline domains were quenched as observed by DSC. The T{dollar}sb{lcub}rm m{rcub}{dollar} for the PEO block was not observed, and the T{dollar}sb{lcub}rm g{rcub}{dollar} for PEOX was slightly shifted to a lower temperature. These results suggest that phase mixing occurs in the amorphous domains of the block copolymer. A block copolymer, 0.75K-0.7K (PEO-b-PEOX) copolymer, containing 50 weight percent PEO showed a T{dollar}sb{lcub}rm m{rcub}{dollar} for the PEO block; however, the transition was broadened relative to the 0.75K PEO precursor.; Poly(propylene carbonate) alternating copolymers were synthesized with zinc glutarate with and without added initiators in an effort to control the molecular weight. The uninitiated copolymerization of propylene oxide and carbon dioxide with zinc glutarate yielded high molecular weight materials in several hours. These materials were amorphous with T{dollar}sb{lcub}rm g{rcub}{dollar} = 37{dollar}spcirc{dollar}C. During the copolymerization, propylene oxide segments and propylene carbonate, a cyclic byproduct, were observed, and quantified by {dollar}sp{lcub}13{rcub}{dollar}C NMR spectroscopy. At 2 weight percent zinc glutarate, the formation of approximately 3 mole percent cyclics, and 9 mole percent propylene oxide segments were observed after 13 hours. With the addition of 1-butanol as an initiator, the rate of the reaction increased. An increase in the yield of the copolymer, and a decrease in the intrinsic viscosity were also observed. However, the mole percent of propylene oxide segments was nearly doubled over the uninitiated system.; The synthesis of poly(ethylene oxide-b-propylene carbonate) copolymers was investigated. Monohydroxy functionalized PEO oligomers ranging from 0.75K-5K were used in this study. Zinc glutarate was used as the catalyst for the block copolymer formation. The 0.75K PEO oligomer yielded approximately 30 percent block copolymer formation. The higher molecular weight PEO oligomers were unsuccessful in initiating the poly(propylene carbonate) block.