Membrane laminate

Much more simply, the same result can be attained with bipolar membranes, membranes consisting of an anion- and cation-permeable (an anion- and cation-exchange) membrane laminated together. At such a membrane, when mounted between electrodes so that the cation-exchange layer faces the anode, water is split into and OH ions so that the acidic and alkaline solutions required for regeneration as above are produced at the respective surfaces of the bipolar membrane. When such membranes are suitably integrated into the sequence of membranes in the electrodialysis unit above, gas evolution at the electrodes is not needed the acid-base pair is produced with about half the power. 

In order to gain some understanding of the behavior of an asymmetric membrane, let s consider a composite membrane consisting of two homogeneous membranes laminated together as shown in Figure 3. The same model has been studied recently by Henkens et al. (10). The first layer solution is ... 

The pore size of the membrane could also be controlled independently of the porosity by altering the size of the salt particles (Fig. 5a). Membranes with high surface area/volume ratios were produced and the ratio was dependent on both salt weight fraction and particle size (Fig. 5b). In addition, the crystallinity of PLLA membranes can be tailored to that desired for each application. These characteristics are all desirable properties of a scaffold for organ regeneration. The major disadvantage of this technique is that it can only be used to produce thin wafers or membranes (up to 2 mm in thickness). A three-dimensional scaffold cannot be directly constructed. This problem may be circumvented however, by membrane lamination. 

Melt molding is an alternative method of constructing three-dimensional scaffolds which has many advantages over membrane lamination. PLGA scaffolds... 

Bipolar membranes consist of an anionic and a cationic membrane laminated together [13]. When placed between two electrodes, as shown in Figure 10.19, the interface between the anionic and cationic membranes becomes depleted of ions. The only way a current can then be carried is by the water splitting reaction, which liberates hydrogen ions that migrate to the cathode and hydroxyl ions that... 

Sano M, Sakamoto M, Hayashi Y, and Kanenori N, Polyurethane compositions with skin care properties, their membranes, laminates containing them, and their manufacture. Patent Japan JP 2005194401. A 2005, 07/21. 

Figure 9.23 The effect of membrane thickness on flux through a coupled transport membrane.20 (Membrane Laminated Celgard 2400/various reagents. Feed 0.2% copper, pH 2.5. Product 100 g/C H2SO4).

Figure 9.24 The effect of membrane thickness on the coupled transport flux of nickel through reaction rate limited membrane.73 (Membrane Laminated Celgard 2400/30% Kelex 100 dissolved in Kermac 470B. Feed 0.2% nickel, pH 6.0. Product 100 g/fi HjSO. ...

The industry trend toward thinner parts (membranes, laminated films) creates a need for a higher colorant loading to maintain color intensity and opacity (Table 13.2). This has driven demand for... 

Considerable research is devoted to high performance Sportswear and even the Ready-to-Wear segments of textiles. The desire is to maintain the body dry by wicking water away as the body generates heat and perspires. To illustrate the concept of diffusion, consider a semi-permeable membrane laminated to a fabric. Assume the sample was placed in a cell separating a column of air from a column of saturated water vapor. The membrane is permeable for water vapor but not air. At time t — 0, thanks to Brownian motion, the water molecules will traverse the membrane and then diffuse through the fabric sample to the air. (Evidently, the fabric sample is usually next to the skin—this example is for illustration purposes only.) The molecular transport through the fabric is referred to as diffusion. 

Gibson, P.W., 2000. Effect of temperature on water vapor transport through polymer membrane laminates. Polym. Test. 19, 673-691. 

From the water vapour permeability point of view, textile materials behave in two different ways first, materials in which moisture vapour transfer takes place predominately by diffusion through air spaces betweeu yams and fibres, following Pick s law. The measured water vapour permeability values are independent of the measuring conditions. Woven, nonwoven, and semipermeable membrane laminates fall into this category. Second are textile material composites that contain a layer of hydrophilic membranes and which behave quite differently. In particular the rate of diffusion through the hydrophilic manbrane is dependent on the test conditions, such as concentration of water vapour in the layer or relative humidity. ... 

Bipolar membrane The membrane consists of an anionic membrane and a cationic membrane laminated... 

Figure 5.9, Homogeneous membrane laminated on the top of a porous substrate membrane. (Two series resistances are connected in parallel.)...

Membrane lamination 3D matrix Lack mechanical strength... 

Figure 3.2 Cross sections of membrane laminates used variously for ion, CO2, O2 and H2O2 (for glucose) sensing, together with the reference electrode design, showing the repeat organisation of polymer, dry electrolyte and thin film-deposited metal conductor.

Effect of Membrane Thickness. Permeation rates were measured through a single membrane, a two-membrane laminate and a three-membrane laminate. HOlOA membranes were used as the support membrane. The effect of total membrane thickness on the permeation rate of CO2 is shown in Figure 4. It is seen that as anticipated, the permeation rate decreases with increasing Ae membrane thickness. 

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