MORPHOLOGICAL ANALYSIS OF PVP COMPOSITE MEMBRANES FOR FACILITATED TRANSPORT PROCESS

فاقد چكيده

Facilitated transport of olefins in the solid state polymeric membranes is based on the concentration fluctuations caused by the reversible interaction of olefins with some transition metals dissolved in a polymer matrix forming metal cation–alkenes complexes. The reversible complexations directly depend on the interactions of the metal cation with its counter anion and with polymer. Also, these interactions can be influenced from type and concentration of polymer and salt. Another membrane structural parameter that changes with salt addition to the polymeric matrix is the crystallinity and glass transition temperature. Crystallinity variation can affect the transportation of olefin molecule against other gas molecules and change the membrane selectivity. The structural effects caused by the formation of carbonyl group-silver ion complexes in systems of poly (N-vinyl pyrrolidone)-water-AgNO3 or Cu(NO3)2 were investigated in this research. First goal of presented study was evaluation of chemical bond energy between oxygen and carbon in the carbonyl groups of PVP. Weakening the interaction between oxygen and carbon could facilitate the complex formation between olefin and oxygen molecules. The second goal was monitoring the crystallinity and glass transition temperature changes of PVP as a result of salt addition. These aims were followed by FTIR-ATR and DSC analysis. Results depicted that increasing the salt concentration could decrease the carbonyl bond (C=O) strength or dependence of oxygen and carbon. Also, addition of salts influences the crystallinity and glass transition temperature.