Ring Nitrogen Compounds And Carbon Dioxide Copolymers And Temperature / Ph The Unika Sex Research

Carbon dioxide as a monomer to synthesis polymer materials is one of the important research topics in the fixation of carbon dioxide. Through the copolymerization of carbon dioxide with aziridine compounds, biodegradable aliphatic polyurethane can be generated. The competition between the homo-polymerization of aziridine and the copolymerization of aziridine with CO₂ leads to the copolymer containing both aliphatic urethanes and amine units. Because of the cleavage of the hydrogen-bonding network involving water and the polymer, as well as hydrophilic aggregation of the polymer, when their proportion reaches some extent, the polymer has a dissolution/precipitation transition in aqueous solution. The unique property of the polymer just like which of poly (N-isopropylacrylamide) containing hydrophobic isopropyl and hydrophilic amide moieties. That is to say, the polymer have a thermosensitive nature. On the other hand, the amine units in the polymer chains are organic base. Therefore, the polymer also behaves pH sensitive.In the first part of the thesis, three aziridine compoumds, unsubstituted aziridine, 2-methylaziridine and N-methylaziridine, as well as different salen metal complexes were synthesized. These compounds and metal complexes were characterized using FT-IR and NMR spectroscopies etc. The prepared salen metal complexes were used to catalyze the copolymerization of CO₂ with aziridine compounds. Results demonstrated that the catalyst was efficient. Several effects of reaction conditions on the copolymerization were discussed, such as the type of metal, the structure of catalyst, the type of aziridine, the reaction temperature and solvent etc.In the second part of the thesis, thermo- and pH- stimuli-responsive behaviours of the polymer were discussed, and the drug release behaviour were also examined.