Gas transport and mechanical properties of PDMS-TFS/LDPE nanocomposite membranes

This study investigates the effect of trimethylsiloxy fumed silica (TFS) on the mechanical and gas permeation properties of polymer nano-composite membranes. The membranes were produced by coating TFS incorporated polydimethylsiloxane (PDMS) at different loadings (5, 10 and 15 wt.%) on a porous low density polyethylene (LDPE) substrate which was formed by a melt-extrusion/salt leaching technique. The PDMS-TFS/ LDPE membranes were characterized by SEM, TGA and DMTA. The results showed that good affinity between the PDMS treated TFS particles and PDMS matrix was obtained leading to improved mechanical and thermal properties. For gas permeation, CH4 and C3H8 at different upstream pressure (50 to 80 psig) and temperature (27 to 55 degrees C) were investigated. The results showed that the C3H8/CH4 ideal selectivity (17.6) and C3H8 permeability (1.89 x 10(4) Barrer) through 10 wt.% TFS loaded membranes (PDMS-TFS10%/ LDPE) were 41 and 14% higher than the neat membranes (PDMS-TFS0%/ LDPE), respectively. The permeation results also indicate that the performance stability under the conditions investigated makes PDMS-TFS/ LDPE membranes interesting for industrial applications.