Gas permeation and sorption properties of non-ionic and cationic amino-hydroxy functionalized poly(dimethylsiloxane) membranes

In order to improve the permselectivity of poly(dimethylsiloxane) (PDMS) membrane without much reduction in permeability value, a new type of poly(dimethylsiloxane) membranes containing different concentrations of non-ionic and cationic amino-hydroxy functionalities has been prepared. IR, 1H NMR and 13C NMR, GPC, DSC, TGA and WAXD techniques were used to characterize the prepared membranes. The gas transport properties, viz., permeability, solubility and diffusivity of the prepared membranes were determined for N2, O2, CH4 and CO2 gases. The fractional free volume present in the PDMS membrane was found to decrease with increasing amino-hydroxy functionality. The permselectivity values for O2/N2 and CO2/CH4 gas pairs were found to increase with increasing concentrations of amino-hydroxy functionalized siloxane. The effect of temperature on gas permeabilities was studied and activation energy was determined for the studied gases.