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A series of sulfonated polystyrene-b-poly(ethylene-r-butylene)-b-polystyrene (S-SEBS) membranes with high water permeability and thermo-mechanical stability were prepared to estimate the membrane utility for heating/ ventilation/air conditioner (HVAC) system. The sulfonation degrees of membranes were controlled by the contents of sulfonating reagent (acetyl sulfate) added. Proton conductivity and water permeation properties of the membranes increased with increasing sulfonation degree. And gas permeation properties were measured to investigate effect of sulfonation of the membranes on permeation properties. Membrane stability with increasing sulfonation degree was also studied.

Currently, polyamide reverse osmosis membranes are highly effective for desalination, industrial process water, and home drinking water. However, they have poor resistance to strong oxidants especially chlorine due to chain cleavage of aromatic polyamide. In general, aromatic polyamide RO membranes are essentially random copolymers consisting of the linear and crosslinked structures. The amide ring is sensitive to attack by chlorine because it is an electron-rich region. Therefore, the activated carbon or sulfite addition processes are essential to remove the chlorine in the separation processes. Many research groups have studied to improve the chlorine-resistance RO membrane having hydrophilic groups (− SO 3 H and − COOH) or nitro groups (− NO 2 ) such as electron acceptors. In this study, thin film composite polyamide RO membranes were prepared by interfacial polymerization method including cross-linking agents having hydroxyl groups to improve the chlorine-resistance. The chlorine-resistance of polyamide RO membrane was influenced by the thermal cross-linking conditions (temperature and time) and cross-linking density of polyamide membranes.

Chang Hyun Lee, Chul Ho Jung, Young Moo Lee*, Ji Won Rhim, Sang Yong Nam School of Chemical Engineering, College of Engineering, Hanyang University, Seoul 133-791, South Korea email: ymlee@hanyang.ac.kr Department of Chemical Engineering, Hannam University, 133 Ojung, Daeduk, Daejon 306-791, South Korea Department of Polymer Science and Engineering, Engineering Research Institute, Gyeongsang National University, Jinju 660-701, South Korea