화학공학소재연구정보센터
Journal of Membrane Science, Vol.376, No.1-2, 188-195, 2011
Gas separation properties of polyether-based polyurethane-silica nanocomposite membranes
In this study, the effect of silica nanoparticles on the gas permeation properties of polyether-based polyurethane membrane was investigated. Polyether-based polyurethane was synthesized by bulk two-step polymerization of polypropylene glycol/hexamethylenediisocyanate (HMDI)/1,4-butanediol (BDO) in mole ratios of 1:3:2. Silica nanoparticles were prepared through the sol-gel method by hydrolysis of tetraethoxysilane (TEOS). Polyurethane and polyurethane-silica nanocomposite membranes were prepared by solution blending and casting method. The prepared polyurethane-silica membranes were characterized using Fourier transform infrared (FIR) spectroscopy, scanning electron microscope (SEM), thermal gravimetery analysis (TGA) and differential scanning calorimetry (DSC) analyses. These methods confirmed the homogenous and nano scale distribution of silica nanoparticles in prepared polymers. Gas permeation properties of polyurethane-silica nanocomposite membranes with silica content of 2.5, 5, 10 and 20 wt.% was studied for pure CO2, CH4, N-2 and O-2 gases. The obtained results indicated the reduction in permeability of all gases, but enhancement in CO2/N-2, CO2/CH4 and O-2/N-2 selectivities was observed by increasing the content of non-permeable silica nanoparticles in polyurethane-silica membranes. In the case of polyurethane-silica (20 wt.%) nanocomposite membrane, the obtained CO2/N-2 selectivity was 1.65 times of pure polyurethane, while the CO2 permeability reduction of polyurethane-silica membranes was 35.6% in comparison with pure polyurethane. Finally, the modified Higuchi model was applied to predict the permeability of polyurethane-silica membranes and fairly good agreement was observed between experimental and predicted gas permeabilities of these membranes. (C) 2011 Elsevier B.V. All rights reserved.