Sulfonated polyphenylene oxide

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. 

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. 

Techniques for chloromethylating polyaiylether sulfones, polyphenylene oxide, phenolic resins, and model compounds were described recently. When the subsequent products are converted... 

Techniques for chloromethylating polyarylether sulfones, polyphenylene oxide, phenolic resins, and model compounds were described recently [191]. When the subsequent products are cmiverted to quaternary amines, there is a decrease in the quatemization rate with increase in degree of substitutimi. This may be due to steric effects imposed by restricted rotation of the polymeric chains [191]. This phenomenon was not observed in quatemization of poly(chloromethyl styrene). The chloromethylation reaction of a polysulfone with chloromethyl ether, catalyzed by stannic chloride, can be illustrated as follows ... 

Polyether sulfone Polyphenylene oxide Polysulfone Polyimide... 

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). 

Kruczek B, Matsuura T. Development and characterization of homogeneous membranes made from high molecular weight sulfonated polyphenylene oxide. J. Membrane Sci. 1998 146 263-275. 

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. 

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. 

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