• Polymer(Korea)
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• v.38 no.6
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• pp.687-693
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• 2014

Poly(ether-block-amide) 1657 (PEBAX 1657) blended membranes with molecular weight 400 poly(ethylene glycol) (PEG 400) were prepared and their permeability was tested for the gases $N_2$, $O_2$, $CH_4$, $CO_2$, and $SO_2$ by the time-lag method. The permeation characteristics were investigated in terms of diffusivity and solubility, which are dominant factors for gas transport. With the addition of PEG 400, the permeability of all the gases increased and also the ideal selectivity for several pair gases was enhanced. In particular, selectivity for $CO_2/N_2$ ranged from 53.2 (pristine PEBAX 1657 membrane) to 84.1 (50% PEG 400 added), for $SO_2/CO_2$ from 38.9 to 50.7, and for $CO_2/CH_4$ from 17.7 to 31.4. The increase of both permeability and selectivity is mainly because of the increase of solubility of the gases, especially $CO_2$ and $SO_2$. To obtain durability against water vapor, glutaraldehyde (GA) was added to the PEBAX 1657/PEG 400 blended membranes. As a result, permeability decreased owing to a reduction of the free volume and ether oxide units, which are the main factors in elevating the permeability for the blended membranes, and selectivity decrease however; we believe that the durability of the resulting membranes would be increased.