Preparation of butadiene-bridged polymethylsiloxane (BBPMS)/ethyl cellulose (EC) hybrid membranes for gas separation

Abstract

Hybrid membranes containing different loadings of butadiene-bridged polymethylsiloxane (BBPMS) in ethyl cellulose (EC) were prepared by an one-pot blending method from a non-isolated solution of polymethylhydrosiloxane (PMHS) reaction with butadiene, and a solution of EC in THF. The semi-crosslinked BBPMS and the BBPMS/EC hybrid membranes having good compatibility were characterized by Fourier transfer infrared (FTIR) and Scanning electron microscopy (SEM). The BBPMS/EC hybrid membranes exhibited good membrane forming ability, heat resistance and mechanical properties. It was worth mentioning that the BBPMS/EC blended membranes exhibit good selectivity for CO2/N2 and O2/N2. Specifically, the blended membrane (BBPMS/EC-5:5) showed the highest ideal selectivities for CO2/N2 and O2/N2 were 25.5 (at a CO2 permeability of 175 Barrer) and 4.85 (at a O2 permeability of 33.2 Barrer), respectively. Compared to the pure EC membrane, the ideal CO2/N4 selectivity and the ideal O2/N2 selectivity of the blended membrane (BBPMS/EC-5:5) were increased by 41.8% and 53.0%, respectively. The modification strategy using semi-crosslinked polysiloxanes to enhance gas transfer of EC is promising for fabrication of high performance CO2 and O2 separation membranes.