• Macromolecular Research
• /
• v.17 no.2
• /
• pp.104-109
• /
• 2009

Solid-state facilitated, olefin transport membranes were prepared by complexation of poly(styrene-b-iso-prene-b-styrene) (SIS) block copolymer and silver salt. Facilitated olefin transport was not observed up to a silver mole fraction of 0.14, representing a threshold concentration, above which transport increased almost linearly with increasing silver salt concentration. This was because firstly the silver ions were selectively coordinated with the C=C bonds of PI blocks up to a silver mole fraction of 0.20, and secondly the coordinative interaction of the silver ions with the aliphatic C=C bond was stronger than that with the aromatic C=C bond, as confirmed by FT-Raman spectroscopy. Small angle X-ray scattering (SAXS) analysis showed that the cylindrical morphology of the neat SIS block copolymer was changed to a disordered structure at low silver concentrations ($0.01{\sim}0.02$). However, at intermediate silver concentrations ($0.15{\sim}0.20$), disordered-ordered structural changes occurred and finally returned to a disordered structure again at higher silver concentrations (>0.33). These results demonstrated that the facilitated olefin transport of SIS/silver salt complex membrancs was significantly affected by their coordinative interactions and nano-structural morphology.

• Macromolecular Research
• /
• v.10 no.2
• /
• pp.80-84
• /
• 2002

Silver species other than the silver ion were formed by UV irradiation on polymer electrolyte membranes containing silver salts and their effect on complexation behavior between the silver and olefin was investigated through the separation performance of olefin/paraffin mixtures. The ideal propylene/propane separation factor reached 350 and the separation coefficient was ca.15 due to the high loading amount of silver ions into poly(2-ethyl-2-oxazoline) (POZ) without UV irradiation. On UV irradiation either in air or under nitrogen, the silver-POZ membranes became yellow-brown initially due to the formation of colloidal silver particles, and finally black and metal-like luster. Even when Ag$^{+}$ was converted, to some extent, to Ag$^{\circ}$ by UV irradiation in air at the early stage, the separation coefficient of olefin/paraffin mixtures was maintained. This suggests that silver species other than the silver ion is active for olefin carrier for facilitated transport. Meanwhile the steady decrease of the separation coefficient was observed in the silver/POZ membranes irradiated under $N_2$. It is suggested that the reduction of silver ions in POZ goes through a different photoreduction mechanism with UV irradiation depending on the environment.t.

• Macromolecular Research
• /
• v.13 no.2
• /
• pp.162-166
• /
• 2005

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.11a
• /
• pp.156-159
• /
• 2004

• Proceedings of the Membrane Society of Korea Conference
• /
• 2002.11a
• /
• pp.69-72
• /
• 2002

No Abstract, See Full Text

• Proceedings of the Membrane Society of Korea Conference
• /
• 2003.11a
• /
• pp.64-67
• /
• 2003

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.152-154
• /
• 2004

A new model of selectively preferential sorption-facilitated transport with fixed site carriers was advanced in this paper. A number of experiments were arranged to demonstrate the ideal above. Preliminary results were obtained from the experiments, and shown the model was applicable for many membrane processes, such as RO, ED, gas separation and liquid membranes etc.

• Macromolecular Research
• /
• v.8 no.1
• /
• pp.1-5
• /
• 2000

The valiclity of the simple mathematical model for facilitated transport in a solid state membrane developed previously has been examined againsts the carrier concentration and membrane thick-ness. Membranes are prepared with copolymer of styrene and 4-vinylpyridine as a matrix and Co(salen) as a carrier. 4-Vinylpyridine is incorporated to provide the coordination site for Co(salen) carrier. Oxygen permeability through the facilitated transport membrane is linearly increased with the square of its thick-ness, as predicted by the mathematical model. However, the oxygen permeability does not increase linearly with the carrier concentration. This seems to be due to the deactivation of the carrier by dimerization at high carrier concentrations as well as the reduced chain mobility by coordination of bulky Co(salen) carrier.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.29-32
• /
• 2004

Reduction of methanol crossover in proton exchange membranes (PEMs) can be achieved by 1) the selection of materials, 2) the morphology control, and 3) the adequate crosslinking [1, 2]. The selection of polymer matrix of PEM for direct methanol fuel cells (DMFCs) is very important because the proton conductivity and methanol permeability are largely dependent upon the properties of polymers.(omitted)

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05a
• /
• pp.78-81
• /
• 2004

Here the effect of various amino acids on the separation performance for these two contrastive membranes is investigated. It was especially focused on the structures of amino acids, and their effects on the silver ion activity as well as the interaction between polymer electrolytes and amino acid. The amino acids studied include asparagine, valine, glutamic acid and lysine.(omitted)