(646e) Influence of Surface-Treated SiO2 on the Transport Behavior of O2 and N2 through Polydimethylsiloxane Nanocomposite Membrane

Mixed matrix membranes were prepared with polydimethylsiloxane (PDMS) and different weight percent surface-treated fumed silica (SiO₂) to investigate the influence of SiO₂ on transport behaviour of O₂ and N₂ gases in the nanocomposite membranes. Fourier transform infrared spectroscopy (FTIR) showed that OH functional group on the surface of SiO₂ was consumed upon incorporation of the silica into the polymer matrix. Thermogravimetric analysis (TGA) results revealed that SiO₂-PDMS has improved thermal property over neat PDMS, supporting the argument that there is good interaction between the polymer and the fumed silica. Scanning electron microscopy (SEM) images of SiO₂-PDMS membranes showed uniform dispersion of SiO₂ nanoparticles in PDMS matrix. SiO₂ nanoparticles disrupted and altered the PDMS polymer chains packing arrangement resulting in different membrane transport behaviour of both O₂ and N₂ gases in SiO₂-PDMS compared to the neat PDMS membrane. While the O₂ flux through SiO₂-PDMS membranes was observed to increase with time, N₂ flux decreased with time before attaining steady state. The 10wt%SiO₂-PDMS membrane exhibited improved performance compared to neat PDMS membranes with O₂/N₂ selectivity and O₂ permeability increased from 2.43 to 3.46 and 520 Barrer to 640 Barrer, respectively, at 30 psig. This improvement is attributed to the influence of the well dispersed SiO₂ nanoparticles in the PDMS matrix.