Microporous membranes Celgard

Figure 2. Scanning electron micrographs of surfaces of microporous membranes made by wet and dry processes. (a) Setela microporous membrane (net process) (b) Celgard microporous membrane (dry process).

Dasgupta and Jacobs [29] patented a concept of using a gel layer in combination with a microporous membrane. The gel layer acts as an adhesive bridge between separator and electrodes, just as in the flat pack Zn/MnC cell [30], The microporous membrane (for example, Celgard membrane) provides excellent mechanical... 

Table 3. Typical properties of some Celgard microporous membranes. ...

Figure 5. Thermal-mechanical analysis of Celgard microporous membranes.

The typical properties of some commercial microporous membranes are summarized in Table 4. Celgard 2730 and Celgard 2400 are single layer PE and PP separators, respectively, while Celgard 2320 and 2325 are trilayer separators of 20 and 25 fim thickness. Asahi and Tonen separators are single layer PE separators made by the wet process. Basic properties, such as thickness, gurley, porosity, melt temperature, and ionic resistivity are reported in Table 4. These properties are defined in section 6.1.3. 

This simple mass transfer model based on simplified film theory has been proposed to describe the process of facilitated transport of penicillin-G across a SLM system [53]. In the authors laboratory, CPC transport using Aliquat-336 as the carrier was studied [56] using microporous hydrophobic polypropylene membrane (Celgard 2400) support and the permeation rate was found to be controlled by diffusion across the membrane. 

Figure 2.29 Scanning electron micrographs at approximately the same magnification of four microporous membranes having approximately the same particle retention, (a) Nuclepore (polycarbonate) nucleation track membrane (b) Celgard (polyethylene) expanded film membrane (c) Millipore cellulose acetate/cellulose nitrate phase separation membrane made by water vapor imbibition (Courtesy of Millipore Corporation, Billerica, MA) (d) anisotropic polysulfone membrane made by the Loeb-Sourirajan phase separation process...

Hydrophobic or hydrophilic microporous membranes PDD-TFE hollow fibers Polypropylene Celgard X-10, X-30 Polypropylene Celgard X-10, X-30... 

Note. (1) Initial composicions feed (a) equimolar 0.005 M solution of o- NA and p-NA in 80% I-octanol and 20% heptane, and(b) equimolarO.Ol M solution of and frart5-stilbene in pure heptane strip (i) 80% I-octanoland20% heptane and (b) pure heptane. Membrane Celgard X-10 microporous hollow fibers. (2) Sour[Pg.319]

The typical properties of some commercial microporous membranes are summarized in Table 6.4. Celgard 2730 and Celgard 2400 are single-layer PE and PP separators, respectively, while Celgard 2320 and 2325 are Trilayer separators of... 

The second reactive inclusion method was developed [129] for microporous membranes. Stretched polypropylene, Celgard 2500 (trademark, Hoechst Celanese Corp.), shows little fine structure after ultrathin sectioning and examination in the TEM (Fig. 4.13A), although SEM study clearly reveals a surface pore structure. In order to enhance contrast, the membrane was treated with an unsaturated surfactant followed by osmium tetroxide staining and ultrathin sectioning. A 1-2% solution of polyoxyethylene allyl ether, Brij 97 (available from ICI Americas Inc.), in 50/50 methanol/water solution was used to... 

Fig. 4.32 FESEM of a Celgard microporous membrane shows (A) that the pores are filling in due to contamination, (B) fibrils are joining together and one pore region is filled, and (C) two fibrils are formed into an X pattern due to time in the electron beam. (From M. Jamieson, unpublished [341].)...

Fig. 5.32 Celgard 2400 microporous membrane surfaces are shown in SEM images taken using a LaBe gun (A), and at 5 kV accelerating voltage with a field emission gun (B). The fibrils, drawn in the machine direction define the pore boundaries. Rows of pores are seen across and into the membrane. (From M. Jamieson, unpublished [162].)...

A method using staining and ultramicrotomy (Section 4.4.2) has been demonstrated that shows the three dimensional structure of microporous membranes. such as Celgard 2500 membrane (trademark, Celanese Corp., New York [131]. Celgard is formed by film extrusion, annealing... 

---