An alternating copolymer of maleic anhydride and ethyl vinyl ether: synthesis in supercritical carbon dioxide, characterization, and properties

摘要

Alternative copolymers of maleic anhydride (MA) and ethyl vinyl ether (EVE) [P(MA-alt-EVE)] were prepared in supercritical carbon dioxide (scCO_(2)). The chemical structure of the obtained P(MA-alt-EVE)s was characterized by FT-IR and ~(13)C NMR spectroscopy and showed that the copolymers possess strictly alternating structure. The influences of MA/EVE feed ratio, reaction time, and solvent as well as the initial initiator concentration on the copolymerization were also studied. It was indicated that the increase rate of reaction pressure could be related with good accuracy to monomer conversion, providing a simple and efficient method for monitoring the reaction processes. Gel Permeation Chromatography examination of the alternative copolymers revealed that the molecular weights of P(MA-alt-EVE) synthesized in scCO_(2) at different pressures were all higher than those prepared in organic solvents. Thermal properties were investigated by TGA and showed P(MA-alt-EVE) has good thermal stability (T _(d)?=?251?°C). Comparison studies on the P(MA-alt-EVE) in scCO_(2) and that prepared in organic solvent exhibit scCO_(2) solvent and it plays an important role in the copolymerization of MA and EVE.