Degree of swelling

The degree of swelling and shrinking is important for design of ion-exchange columns, especiaUy for the location of the distributors used to disperse incoming fluids, and coUect outgoing ones, evenly over the cross-sectional area of the resin bed. Once placed, these distributors are not adjustable. The upper distributor should be above (the lower one below) the resin bed, even in the bed s swoUen form. 

Liquid Degree of swelling Liquid Degree of swelling... 

Table 12. Temperature-Dependence of Degree of Swelling in Four Liquids ...

Compatibility and Corrosion. Gas turbine fuels must be compatible with the elastomeric materials and metals used in fuel systems. Elastomers are used for O-rings, seals, and hoses as well as pump parts and tank coatings. Polymers tend to swell and to improve their sealing abiUty when in contact with aromatics, but degree of swell is a function of both elastomer-type and aromatic molecular weight. Rubbers can also be attacked by peroxides that form in fuels that are not properly inhibited (see Elastomers, synthetic Rubber, natural). 

For rubbeiy membranes (hydrophobic), the degree of swelling has less effect on selectivity. Thus the permeate pressure is less critical to the separation, but it is critical to the driving force, thus flux, since the vapor pressure of the organic will be high compared to that of water. 

The conventionally covalently cross-linked rubbers and plastics cannot dissolve without chemical change. They will, however, swell in solvents of similar solubility parameter, the degree of swelling decreasing with increase in cross-link density. The solution properties of the thermoelastomers which are two-phase materials are much more complex, depending on whether or not the rubber phase and the resin domains are dissolved by the solvent. 

The successful development of eye contact lenses led in turn to a demand for soft contact lenses. Such a demand was eventually met by the preparation of copolymers using a combination of an acrylic ester monomer such as methyl methacrylate, a cross-linkable monomer such as a dimethacrylate, and a monomer whose homopolymer is soluble or highly swollen in water such as N-vinyl pyrrolidone. Such copolymers swell in water (hence the term hydrophilic), the degree of swelling being controlled by the specific type and amount of the monomers used. In use the lens is swollen to equilibrium in water, a typical soft lens having a water content of about 75%. 

Quell-gas, n. gas from springs, -grad, m. degree of swelling, -kuppe,/. Geol.) volcanic plug. 

Figure 4 (a) Polymerization time versus degree of swelling (in toluene) curves for styrene-PEG crosslinked copolymers initiated by macroinimers ( ) MAIM-200, ( ) MAIM-400, (O) MAIM-600, (A) MAIM-1000, and ( ) MAIM-1500. (b) Polymerization time versus degree of swelling (in water) curves for styrene-PEG crosslinked copolymers initiated by ( ) MAIM-1500 and ( ) MAIM-400. Source Ref. 50. 

Fig. 28. Effect of degree of swelling on diffusion coefficient of streptomycin in carboxylic cation exchangers /) KB-4, 2) KFA, J) KB-2, 4) KMDM-6...

In one of these groups the polymer network consisting of synthetic and natural polymers is formed directly in the process of grafting. The degree of swelling is determined by the reaction condititions including the component ratio, initiation method, and ionogenic monomer content. 

In [191] it has been shown that the degree of swelling of the melt (d D-1)2 may be determined from ... 

As is common in most polymer reactor design problems, heat transfer is one of the major process concerns. For example, if the heat transfer is primarily through the wall of a jacketed reactor, the overall heat transfer coefficient is a function of both the agitator configuration and the degree of swelling of the particles. 

The results in Table 13.2 indicate that the degree of swell decreases in the order of products capped with ammonia, 2-aminoethanol, diisopropanolamine, and diethanolamine, which is in line... 

For the purpose of testing the validity of what we have called the deformation factor, it is convenient to plot rl a — l/a ) vs. a if rubbers swollen permanently (not merely for purposes of equilibration) are included, the quantity roV2 /(a — l/a ) is to be preferred, where To is the tension referred to the cross section when unswollen and unstretched, and V2 is the volume fraction of polymer in the swollen mixture (see Appendix B, Eq. B-5). According to theory, both of these quantities should be independent of the deformation, and the latter should be independent of the degree of swelling as well. On the basis... 

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