The effects of ethereal chain extenders on the gas separation properties of the polyurethane membranes
Paper ID : 1216-MST2015-FULL
Ali Pournaghshband Isfahani1, Behnam Ghalei2, Morteza Sadeghi *3, Easan Sivaniah4
1Chemical Engineering Department, Isfahan University of Technology, Isfahan 84156-8311
2Institute for Integrated Cell-Material Science (iCeMS), Kyoto University, Kyoto 606-8501
3isfahan university of technology
4Institute for Integrated Cell-Material Science (iCeMS), Kyoto University,
In this study, three chain extenders with the same length and different functionalities (i.e. diol and diamine) and ethereal groups were used to investigate the effects of mobility of the hard segments and the extent of hydrogen bonding interaction on the gas permeability of the polyether based polyurethane membranes. Fourier transform infrared (ATR-FTIR) and wide angle X-Ray diffraction (WAXD) were used to study the phase separation and crystallinity of the prepared polyurethanes. FTIR results indicate more phase mixing in the presence of ethereal groups in the chain extenders, which might be due to more compatibility of the chain extender with the used polyether as the soft segment. Also, more phase separation was observed in the polyurethane synthesized by diamine chain extender compared to diol one. Gas transport properties of pure gases including CO2, CH4, O2, N2 for all synthesized polyurethanes were explored at 25oC and 4 bar. 1,8-Diaminooctane based-PU shows the highest permeability (up to 160 Barrerfor CO2) compared to other chain extenders (3,6-dioxa-1,8-octanediol and 3,6-dioxa-1,8-octanediamine), which is in good agreement with the phase separation results. Also, the polyurethane-urea shows better gas separation performance than polyurethane membrane. The phase separation has a remarkable effect on the gas permeability of the polyurethane membranes. Higher phase separation usually invokes to make a high permeable polyurethane membrane.
Polyurethane membrane, gas separation, chain extender, phase separation
Status : Paper Accepted (Poster Presentation)