Recently, poly(dimethylsiloxane)(PDMS) membrane has become researchers' best choice for VOCs recovery especially higher hydrocarbons(C3+) recovery owing to its high gas permeability and vapor selectivity. However, the vapor selectivity and mechanical properties value remain to be improved. Fumed silica has been found to have a positive effect on the separation properties when combined with glassy polymer membranes like PTMSP, while few studies investigate its effects on rubbery polymers in terms of gas separation system.In this study, both neat PDMS membranes and hydrophobic fumed silica filled PDMS nanocomposite membranes over a spongy porous PVDF support were fabricated for the separation of propane/nitrogen mixed gases. the neat PDMS membranes prepared showed better separation performance than most literature reports. The separation factor for propane/nitrogen can reach up to 13.5 with a propane permeance of over 170 GPU. For PDMS/fumed silica composite membranes, effects of the loading amount of silica were examined. SEM showed that the surface modified hydrophobic fumed silica exhibited a good affinity with the PDMS polymer matrix. Moreover, fumed silica effectively enhanced the sorption of propane into the polymer matrix leading to improved vapor selectivity as expected. With the increase of silica loading content, the separation factor increased. However, over loading of silica caused selectivity decreases for possible particle aggregation. Lastly, the mechanical properties were greatly reinforced making it a robust membrane material for potential industrial applications.Acknowledgements The authors greatly appreciate the financial supports of the National High Technology Research and Development Program of China (No. 2012AA03A607), National Natural Science Foundation of China (21176135, 21206001), Beijing Foundation(PXM2013_178203_000004,2132010).

Poly(dimethylsiloxane)/fumed silica nanocomposite membranes with enhanced propane/nitrogen separation performance

247th National Meeting (2014)

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