Membrane,synthetic preparation

Membranes can be prepared from both ceramic and polymeric materials. Ceramic materials have several advantages over polymeric materials, such as higher chemical and thermal stability. However, the market share of polymeric membranes is far greater than ceramic membranes as the polymeric materials are easier to process and less expensive. A handful of technical polymers are currently used as membrane materials for 95% of all practical applications [2]. Polymeric materials that are used to prepare separation membranes are mostly organic compounds. A number of different techniques are available to prepare synthetic membranes. 

A number of different techniques are available to prepare synthetic membranes, ome of these techniques can be used to prepare polymeric as well as inorganic cmbranes. The most important techniques are sintering, stretching, track-etching, phase... 

Enzyme membranes can be prepared by adsorbing the enzyme on the surface of a suitable native or synthetic membrane, or, in the case of membranes with large pores, by impregnating the whole membrane with enzyme. The resulting enzyme membrane can be stabilized by covalently cross-linking the adsorbed protein with a suitable bifunctional reagent (8 ). 

R. Katoh, Y. Asano, A. Furuya, K. Sotoyama, and M. Tomita Preparation of Food Emulsions Using Membrane Emulsification System. Proceedings of the 7th International Symposium on Synthetic Membranes in Science 407, Tubingen, Germany (1994). 

Yasuda, H. "Composite Reverse Osmosis Membranes Prepared by Plasma Polymerization," in "Reverse Osmosis and Synthetic Membranes," Sourirajan, S., Ed., National Research Council, Canada, Ottawa, 1977, p.263. 

Figure 3.16 Equipment to prepare microporous membranes by the polymer precipitation by cooling technique [37]. Reprinted with permission from W.C. Hiatt, G.H. Vitzthum, K.B. Wagener, K. Gerlach and C. Josefiak, Microporous Membranes via Upper Critical Temperature Phase Separation, in Materials Science of Synthetic Membranes, D.R. Lloyd (ed.), ACS Symposium Series Number 269, Washington, DC. Copyright 1985, American Chemical Society and American Pharmaceutical Association...

J.G. Wijmans and C.A. Smolders, Preparation of Anisotropic Membranes by the Phase Inversion Process, in Synthetic Membranes Science, Engineering, and Applications, P.M. Bungay, H.K. Lonsdale and M.N. de Pinho (eds), D. Reidel, Dordrecht, pp. 39-56 (1986). 

Such relationships can be useful in designing synthetic membranes having properties similar to natural systems. For example, Equation 4 correlates the change in resistance caused by alcohols on potassium ion permeability of black lipid membrane (BLM) prepared from the lipid of sheep erythrocytes. The rather large negative intercept of Equation 4 indicates that three times the concentration of isolipophilic alcohol is needed to change the resistance of the BLM as is needed to cause hemolysis. Although the two processes are quite different, the role of hydrophobic forces in each can be compared. 

Sample Preparation Using Synthetic Membranes for the Study of Biopolymers By Matrix Assisted Laser Desorption/Ionization Mass Spectrometry... 

In this paper, we report the use of several micro-porous synthetic membranes to prepare contaminated peptides and proteins for MALDl-TOF analysis. By spotting contaminated samples directly onto activated synthetic membranes, impurities such as salts, glycerol, and detergents can be washed from the sample, while biopolymers remain intact. Following addition of matrix, samples can be desorbed and ionized... 

Improvement in mass resolution by MALDI of samples loaded on synthetic membranes was particularly apparent in the MALDI of contaminated samples. We systematically examined the ability to remove measured amounts of contaminants from peptide and protein samples by doping previously pure samples with glycerol and salts. Samples doped with 5 % glycerol and 500 mM sodium were prepared for MALDI-MS analysis using the method described above. 

Strathmann, H. Synthetic membranes and their preparation. In Handbook of Industrial Membrane Technology, Porter, M.C., Ed. Noyes Publications Westwood, New Jersey, 1990 1 pp. 

The various chapters in this book address the topics of material selection, characterization and evaluation as well as membrane preparation, characterization and evaluation. At the expense of neglecting membranes for applications such as controlled release and impermeable barriers, this book focuses on synthetic membranes for separation processes as well as active membranes and conductive membranes. While many of the concepts developed herein can be extrapolated to other applications, the Interested reader is referred elsewhere for specific details (for example, controlled release (25-30), coating and packaging barriers (31-33), contact lenses (34,35), devolatilization (36), ion-selective membrane electrodes (37-42) and membranes in electrochemical power sources (43)). 

The literature describes numerous manufacturing methods for synthetic membranes. A recent review by Pusch and Walch (1) considers membranes from a number of techniques for manufacturing membranes and discusses applications ranging from microfiltration to desalination to gas separation. In this paper, a thermal phase-separation technique of preparing membranes Is presented. The method Is a development of an Invention described In US Patent 4,247,498 by Anthony J. Castro (,2). This technique Is similar In many respects to the classical phase-inversion methods however, the additional consideration of thermal solubility characteristics of the poly-mer/solvent pair offers new possibilities to membrane production. 

In addition to blocatalytlc, energy-transducing and Information transducing membranes, there are, of course, other types of blofunctlonal synthetic membranes. However, this review concentrates on these three Important blofunctlonal membranes. The historical background of their development, the molecular mechanism In biological membranes on which blofunctlonal synthetic membranes are modelled, the methodology of membrane preparation and current trends In the research and development are described. 

Matrices for Blocatalytlc Synthetic Membranes. Blocatalyst-bound synthetic membranes have been prepared by the following four methods ... 

Photo-responsive Synthetic Membranes. Although the visual Information transduction Is too complexed to be realized in vitro, the photoeffects of retinal-containing synthetic membranes have been investigated. Alzawa et al. (74) prepared a photo-responsive membrane from a solution of 11-cis retinal, phosphatidyl choline and trlacetyl cellulose. The retinal was assumed to be incorporated into the molecular assemblies of phosphatidyl choline, which were dispersed In the trlacetyl cellulose membrane matrix. The membrane responded to visible light by showing a transmembrane potential in association with the photoisomerization of membrane-bound 11-cis retinal. On the other hand, a membrane Incorporating 11-cls retinal without phosphatidyl choline exhibited little light-induced transmembrane potential (75). 

Pusch W, Walch A, Synthetic membranes - Preparation, structure and application. Angew. Chem. Int. Ed. Engl. 1982 21, 660-685. 

Belfort, 6. Sinai, N. Sterling, D., "The State of Water in Synthetic Membranes and Aqueous Solutions." Second Annual Report, Jan., 1977 - Sept. 1977, project no. 848092, prepared for the NCRD, Prime Ministers Office, Jerusalem, Israel and GKSS, Baudesministerium fur Forshung und Technologie, West Germany, (March 1978). 

DISCUSSION OF TECHNICAL RELEVANT SYNTHETIC MEMBRANES AND METHODS OF THEIR PREPARATION... 

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