Membranes shrinkage

Water Content. Figure 4 shows the relation between the water content of perfluorocarboxylic acid membrane prepared by chemical treatment and the ion exchange capacity with varying external solution concentration. As the concentration of the external solution increases, the membrane shrinkage increases and the water content is therefore decreased. The influence of... 

Cell morphology of foamed PVC depends on concentration of a plasticizer, surface treatment of filler and foaming time and temperature. High concentrations of plasticizers produced poly disperse cell structure. Polyester plasticizer blends are useful for production of heat-shrinkable film. Plasticizer migration from geomembranes causes membrane shrinkage. ... 

For example, more and more manufacturers, contractors, consultants, and building owners are turning to these techniques to solve in-service roofing membrane problems as well as to evaluate new roofing membrane materials. A typical example is the paper on the problem of EPDM membrane shrinkage The study was conducted in 1995 to investigate the causes of... 

Whereas the above studies have attempted to identify the Na /H exchanger in renal brush border membranes (a resistant-type), at least one study has reported possible identification of a sensitive-type transport protein [49]. The Na /H exchanger in lymphocytes (a sensitive-type) can be activated by either 12-0-tetradeca-noylphorbol 13-acetate (TPA) or osmotic shrinkage. TPA or osmotic shrinkage... 

During the process, the solute diffuses into the intercellular space and, depending on the characteristics of the solute, it may pass through the membrane and enter the intracellular space. Differences in chemical potentials of water and solutes in the system result in fluxes of several components of the material and solution water drain and solute uptake are the two main simultaneous flows. Together with the changes in chemical composition of the food material, structural changes such as shrinkage, porosity reduction, and cell collapse take place and influence mass transfer behavior in the tissue. 

The hollow-fiber systems for gas separation or the tubular microfiltration systems have to be pyrolyzed before mounting in the membrane housing, because of the large shrinkage during pyrolysis. That is the most critical step in the fabrication of a separation system. 

If the pH is lowered to about 6.0 the SFV particle undergoes a dramatic decrease in diameter of about 70 A which is due to the contraction of the nucleocapsid (Sfiderlund et al, 1972 von Bonsdorff, 1973). The viral membrane apparently adheres to the nucleocapsid during the contraction, and excess membrane is extruded in the form of blebs. Interestingly, few spike proteins are seen on these blebs suggesting that they contain only lipid and that the spike proteins remain bound to the nucleocapsid during shrinkage. 

Other MFl-type zeolite-sorbate systems are known to exhibit similar behavior. In a recent study, Yu et al. [34] reported that at saturated loadings of -hexane a single MFl-type zeolite unit cell has an overall volume expansion of 2.3%, which can correlate to shrinkage in non-zeoUtic pores up to 7 nm for a 1 tm crystal when isotropic expansion is assumed. It was demonstrated that, even in membranes with large number of defects, the crystallite swelling caused the membrane to achieve significant separation between n-hexane and trimethylbenzene, iso-octane and 2,2-dimethylbutane using pervaporation [34]. 

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