Fabrication and characterization of Poly(vinylidene fluoride)/Matrimid blend membrane for CO2/CH4 separation

Flat sheet membranes of polyvinylidene fluoride (PVDF)/Matrimid@5218 were fabricated by solution casting method. The effect of Matrimid content on physicochemical, morphological, and gas separation properties of PVDF membrane was investigated. The CO2 permeability and CO2/CH4 selectivity of the optimum blend membrane (PVDF/Matrimid (95/5)) increased about 117% (from 0.952 to 2.065 Barrer) and 48% (from 23.21 to 34.41) compared to pristine PVDF, respectively. For 10 wt% content of Matrimid, CO2 permeability increased from 0.952 to 3.117 Barrer, while CO2/CH4 selectivity decreases because of partial miscibility and phase separation of two polymers. The miscibility of blends with 5 wt% Matrimid was confirmed as illustration by differential scanning calorimetry (DSC). Chemical structure and morphology of prepared membranes were characterized using Fourrier transform infrared (FTIR) and scanning electron microscopy (SEM).