Sulfonated polyphenylene oxide membranes

Plummer, C.W. Kimura, G. and LaConti, A.B. "Development of Sulfonated Polyphenylene Oxide Membranes for Reverse Osmosis",... 

After the initial work on asymmetric sulfonated polyphenylene oxide membranes, sulfonated polysulfone was subsequently examined by several research groups. However, the appearance of patents in 1973 and 1977 by Rhone-PoulencM 8S covering asymmetric membranes of sulfonated polysulfones appeared to dampen such research efforts. Also, a basic problem with sulfonated polysulfone was the fact that salt rejections fell rapidly when a critical level of sulfonation was exceeded, but water fluxes were too low until this sulfonation level was exceeded. 

Kruczek B, Matsuura T. Effect of metal substitution of high molecular weight sulfonated polyphenylene oxide membranes on their gas separation performance. J, Membrane Sci. 2000 167 203-216. 

C.W. Plummer, G. Kimura and A.B. LaConti, Development of Sulfonated Polyphenylene Oxide Membrane for Reverse Osmosis. In Research and Development Progress Report 557, Office of Saline Water, United States Department of Interior, (1970). 

Plummer C. W., Kimura G., and La Conti A. B., Development of Sulfonated Polyphenylene Oxide Membranes for Reverse Osmosis, Office of Saline Water Research and Development Progress Report No. 551, General Electric Company, Lynn, Massachusetts, 1970. 

Another method of preparing NF membranes is to dip-coat a thin layer of sulfonated polyphenylene oxide (SPPO), sulfonated polysulfone (SPS), or carboxylated polysulfone on a porous substrate membrane. 

Sulfonated poly(2,6- dimethyl-1,4-phenylene oxide) (SPPO) Cross-Unked bromomethylated sulfonated polyphenylene oxide (BPPO) The composite membranes had lower conductivity of 0.03-0.07 S/cm compared with SPPO of 0.09-0.15 S/cm but much lower water swelling ratio and improved fuel cell performance [79, 80]... 

Salemme RM. Sulfonated polyphenylene oxide as a permselective membrane for water vapor transport. USA patent 3,735,559 (1973). 

The most widely used chemically modified PPO in the development of thin film composite membranes is sulfonated polyphenylene oxide (SPPO). The polymer in the acid form as well as salt form has been used by Bikson to produce multilayer composite membranes. These types of membranes have been described to have at least two chemically distinct layers deposited on a porous substrate in a single coating step process. The outer layer forms a protective defect-sealing surface whereas the inner layer is the selective SPPO layer. This layer is adjacent to the porous support membrane. The two top layers are formed simultaneously on top of porous polysulfone support hollow fibers. A coating solution of SPPO in the lithium salt form (SPPO-Li ) and amine functional silicone fluid was coated on top of the polysulfone fibers. These coated fibers were used to construct a hollow fiber separator permeator. 

Kruczek B. and Matsuura T., Development and Characterization of Homogeneous Membranes from High Molecular Weight Sulfonated Polyphenylene Oxide, J. Membrane Sci., 1998,146, 263-275. 

Sulfonation of aromatic polymers has been explored as a method to produce hydrophilic polymers with water permeability and salt rejection characteristics. These have been of interest because of their potentially high degree of chlorine resistance. The use of sulfonated aromatic polymers for reverse osmosis membranes began in the late 1960 s with the work of Plummer, Kimura and LaConti of General Electric Company.82 Polyphenylene oxide [poly(2,6-di-... 

Fu H, Jia L, Xu J. Studies on the sulfonation of polyphenylene oxide (PPO) and permeation behavior of gases and water vapor through sulfonated PPO membranes. I. Sulfonation of PPO and characterization of the products. J. Appl. Polym. Sci., 1994 51 1399-404. 

The sulfonation of PPO was done using chlorosulfonic acid. SPPO with an lEC value of 1.3 to 2.5 was prepared by chlorosulfonation of 2,6-dimethyl polyphenylene oxide in chloroform solvent. Modified SPPO polymer (SP3O) (R.M. Dempsey and A.B. LaConti, USA/MERDC Contract No. DAAK02-73-C-0407, 1974) was also prepared by partial bromonation and subsequent sulfonation of 2,6 diphenyl polyphenylene oxide. The lEC values of the modified SPPO were in the range of 1.3 to 1.5. Polymers were vacuum dried for 72 hours and dissolved in solvent mixtures. The casting solution concentrations were 6 to 7 % polymer in CHCls/alcohol or CH3N02/alcohol mixtures when porous polypropylene and polysulfone membranes, respectively, were used as the substrate membranes. 

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