We developed a novel aluminum-based initiator for epoxide polymerization which facilitated polymerization of various epoxides (epichlorohydrin, propylene oxide, etc.) and episulfide up to molecular weights of 100 kg/mol while maintaining relatively narrow polydispersity (Ð < 1.3). The initiator was simply synthesized through the reaction of a thiol ligand and trialkyl aluminum, with the thiol ligand choice enabling polymer end group control. Copolymerization of epichlorohydrin and propylene oxide and copolymerization of different epoxides with episulfide demonstrated the ability of this method to control polymer architecture. We further investigated the effect of catalyst concentration and initiator structure on the kinetics of epoxide polymerizations through 1H NMR spectroscopy. Finally, we combined our method of polymerization with another facile method, reversible addition fragmentation with chain transfer (RAFT) polymerization, to synthesize block-co-polymers made from vinyl and epoxide monomers. To do this, we made a macroinitiator from polystyrene (PS) and poly(methyl methacrylate) (PMMA), synthesized by RAFT polymerization, and further polymerized epoxide from it. Therefore, this new synthetic tool allows for the facile and controlled polymerization of epoxides into well-defined, functional, polyether materials. Furthermore, the introduced innovative and reliable methodology for the synthesis of SAl initiators enabled us to tune the polymer architecture to readily access more complex structure of polyepisulifides. We synthesized di-functional (d-H) and tetra-functional (t-H) SAl initiators to produce ABA and star-(co)polymers consisting of propylene sulfide and PO or ECH. Finally, polyethylene glycol (PEG) was used as a macroinitiator to create PEG-b-PPS block copolymers and characterized by 1H, 13C NMR spectroscopy, DOSY, DSC, and SEC. Motivated by the result, we prepared the star shape cross linked membrane from t-H initiator. The composition was controlled through the monomer feed ratio of propylene oxide (PO) and epichlorohydrin (ECH) for synthesis of PPO-PECH membrane in the presence of poly(ethylene oxide)-diglycidyl ether as a cross linker and the most optimized PPO-PECH with the ratio of 90:10 resulted optically clear and flexible film. We further modified the membrane with a range of amines like trimethylamine (TEA), dimethylamine (DMA), triethylamine (TEA), and diethylamine (DEA) by membrane dipping method. The chemical, physical, and mechanical properties of resultant secondary amine grafted and quartenized membranes were characterized as a candidate for CO2 transport. Moreover, we designed the facilitated transport membranes of crosslinked ether-based PPO-PECH membranes with the range of hindered and unhindered primary amines using previously reported mono(μ-alkoxo)- bis(alkylaluminum) (MOB). The physical and chemical properties of the membranes investigated by FT-IR spectroscopy, DSC, TGA, and rheology. This method demonstrated a simple and robust strategy to prepare copolymers cross linked membranes containing amines for CO2 transport. This enables us to compare the effect of different amines in the structure of facilitated transport membranes. In this thesis research we seek to develop a SAl initiator as a platform that is both simple to use and can synthesize new polymeric materials. This methodology is simple and tunable to produce robust crosslinked membranes for molecu
Read
