Polymer concentration had been identified as one of the important parameters tailoring the membrane properties. In this work, the effects of polymer concentration on the morphological and mechanical properties of membrane were investigated at three different polymer concentrations, i.e., 20, 25 and 30 wt%. The viscosity of dope solutions were determined to estimate the optimum polymer concentration.  The morphological properties of the fabricated membrane were determined using SEM whereas the mechanical properties of the membrane were investigated using tensile tester. Results show that an increase in the polymer concentration could lead to the improvement of the morphological and mechanical properties of the membrane. The tensile strength of the membrane determined for PSf-20, PSf-25 and PSf-30 are 5.73, 6.59 and 7.03 MPa, respectively whereas the elongation at break measured for the membranes are 46.99%, 69.18% and 36.27%, respectively. As shown in this work, the polymer concentration played a significant role to alter on membrane morphology and mechanical strength.

Asymmetric hybrid organic-inorganic clay mineral polyethersulfone (PES) flat sheet membranes were prepared from solution containing Cloisite15A® (C15A) in the mixture of solvent and polymer. Neat PES and MMM were prepared through dry/wet phase inversion method. The newly developed membranes were characterized by means of SEM. The effect of filler addition, evaporation time and coating protocol towards the performance of the membrane was investigated. The measurement was carried out at room temperature and the upstream pressure was 3 bar while the downstream pressure was atmospheric. Experimental results showed that selectivity for MMM fabricated with 0.25 wt% clay loading at evaporation time of 40 s is lower compared to those prepared at higher evaporation time. After coating with silicone rubber solution and heat treated, the resultant membranes exhibited selectivity enhancement of CO2/CH4 from 7.9 to 28.4 for pristine PES, while PES/C15A1 and PES/C15A2 showed a selectivity improvement of 2.29 to 18.72 and 10.24 to 33.49 each. Optimum evaporation time and appropriate coating and heat treatment have significant contribution in developing high performance MMM for gas CO2/CH4 separation.