Casting polymeric

Water Permeation and Solute Separation through the Membrane. The measurements of water permeability of the 67 membranes prepared under different conditions were carried out by using an Amicon Diaflo Cell (effective membrane area, 13.9 cm2) under a pressure of 3 kg/cm2 at 25 °C. Some results are listed in Table 1067. It is apparent that much higher water absorption and permeability than the cellulosic membrane are characteristic of the 67 membranes prepared by both the casting polymerization and conventional casting. 

The permeability tests for alkali metal ions in the aqueous solution were also conducted. When an aqueous salt solution moves to cell 2 through the membrane from cell 1, the apparent diffusion coefficient of the salt D can be deduced from a relationship among the cell volumes Vj and V2, the solution concentration cx and c2, the thickness of membrane, and time t6 . In Table 12, permeabilities of potassium chloride and sodium chloride through the 67 membrane prepared by the casting polymerization technique from the monomer solution in THF or DMSO are compared with each other and with that the permeability through Visking dialyzer tubing. The... 

Schildknecht, C. E. Cast Polymerizations, Chap. 2 and Other Bulk Polymerizations, Chap. 4 in Polymerization Processes, C. E. Schildknecht, ed. (with I. Skeist), Wiley-Interscience, New York, 1977. 

The most common type of uniaxial extension can take place during simple tensile drawing of cast polymeric sheets. In this case, the two ends are gripped and the material is pulled to extend, and then chain extension and crystallite rearrangement takes place. 

Phase inversion refers to the controlled transformation of a cast polymeric solution from a Hquid into a soHd state. During the phase-inversion process, a thermodynamically stable polymer solution is usually subjected to controlled Hquid-H-quid derabdng. This phase separation of the cast polymer solution into a polymer-rich and a polymer-lean phase can be induced by immersion in a non-solvent bath ( immersion precipitation ), by evaporating the volatile solvent from a polymer that was dissolved in a solvent/non-solvent mixture ( controlled evaporation ), by lowering the temperature ( thermal precipitation ) or by placing the cast film in a vapor phase that consists of a non-solvent saturated with a solvent ( precipitation from vapor phase ) [1]. 

Diethylene glycol bis(allyl carbonate). This liquid mouomer can be polymerized by peroxide and heat (Fig. 3.19). When carefully cast, polymerized, and cured, it gives transparent, colorless castings of high refractive index, high hardness, and therefore scratch resistance. It is used for spectacle lenses. 

The work used samples obtained by means of casting polymerization in the shape of disks with diameter 20-40 mm and thickness mm Fixation of samples under study was affected by radiation of mercury lamp at 436 nm or that of "blue" LED with maximum of radiation band at 470 nm. Schematic diagram of information recording in such medium is shown on Fig. 7b by the example of constructing a hologram-grating. 

CE. Schildknecht, Cast polymerization, other bulk polymerizations , in Polymerization Processes , CE. Schildknecht, I. Skeist, eds, WUey Interscience, New York, Chs 2, 4,1977... 

F.G. Paulsen, S.S. Shojaie, and W.B. Krantz, Effect of evaporation step on macro- void formation in wet-cast polymeric membranes. Journal of Membrane Science 91 (1994) 265-282. 

A review of literature on factors affecting physical properties of solution-cast polymeric films points to the solvent in casting solution as the most important factor [47]. This is because the nature of solvent affects chain conformation, size and asymmetry of the polymer coil in dense films [16]. In many cases, however, the effect of solvent might simply be related to the effect of residual solvent in polymeric films, because the removal of residual solvent from glassy polymers is very difficult. 

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