Significantly enhanced CH4 permeability base on poly(styrene-b-butadiene-b-styrene)-poly(dimethylsiloxane-co-methylhydrosiloxane) crosslinked membranes

Poly(styrene-b-butadiene-b-styrene) triblock co polymer (SBS) crosslinked membranes containing poly(dimethylsiloxane- co -methylhydrosiloxane) (PDMS- co -PMHS) were prepared by hydrosilylation reaction toward CH 4 /N 2 separation. The effect of an additive amount of PDMS- co -PMHS on the structure, morphology, and thermodynamic stability of crosslinked membranes were investigated by using FT-IR, SEM and TGA . Soxhlet extraction experiments were also performed to explore the crosslinking degree of membranes. In this work, the single-gas permeability of CH 4 and N 2 was measured using the constant volume–variable pressure method. Our experimental results showed that crosslinked membranes can significantly enhance CH 4 permeability with increasing PDMS- co -PMHS content, whereas the CH 4 /N 2 selectivity remains unchanged. Among these crosslinked membranes, the SBS-c-PDMS- co -PMHS-70 membrane exhibited optimal CH 4 permeability at room temperature and the pressure of 1   bar. Specifically, the CH 4 permeability was >   10-folds higher than that of the SBS membranes (37.6 barrer versus 443.6 barrer). Moreover, investigation of the effect of test temperature on the gas permeation of crosslinked membranes revealed a preferable CH 4 permeability at 55   °C and 1   bar, at which the CH 4 permeability reaches 679.2 barrer without a substantial compromise in selectivity.