Capacity swelling

This equation may be used for the estimation of the swelling capacity of the activated seed particles with the monomer. A typical graph sketched based on Eq. (11) is given in Fig. 18. This graph shows the variation of the swelling capacity of the seed polymer particles VmIVp) with the ratio of interfacial tension-initial particle radius... 

Cross-hnked polyacrylamides are a group of hydrophihc solid supports introduced primarily for preparation of biopolymers (Fig. 4). Unhke PS resins, polyacrylamides have excellent swelling capacity in both protic (water, alcohols) and aprotic (dichloromethane, dimethylformamide) solvents [88]. These beads are stable towards bases, acids, and weak reducing and oxidizing agents [89]. Predictably, conditions under which amide bonds are cleaved (i.e., sodium in liquid ammonia) [90] lead to rapid decomposition of the polymer. 

Seeligmann, Torrilhon, and Falconnet, in a treatise on rubber published in France in 1896, recorded interesting early observations on the sol and gel components now known to be present in most specimens of undegraded raw rubber. They referred to them as the two isomeric hydrocarbides of rubber, one being the adhesive principle and the other the nervous principle. It was observed that the latter refused to dissolve on repeated treatment with fresh portions of solvent and that the approximate percentage of this constituent was roughly the same when different solvents were used to extract the soluble portion. The authors called attention also to the enormous swelling capacity of the nervous hydrocarbide. Vulcanization was attributed to a reaction of sulfur with the adhesive principle whereby the adhesive characteristics are suppressed or eliminated. 

The general requirements for a support are mechanical stability and chemical inertness under the reaction conditions to be used. Mechanical stability is required to avoid the breaking down of the polymer into smaller particles, which could lead to the clogging of filters. Supports also need to be chemically functionalized, so that the synthetic intermediates can be covalently attached to the support via a suitable linker. Moreover, if the intermediates are located within the support (and not only on the surface), diffusion of reagents into the support particles will be necessary, and materials with sufficient permeability or swelling capacity need to be chosen. 

The membrane swelling capacity (or gel water content) is defined as the percentage ratio of the difference between the mass of a wet sample (mw), equilibrated in deionized water for 2 days, and that of the same sample (mD), dried at 75°C over phosphorous oxide (P2O5) under vacuum, by mD (Strathmann, 1992). 

The morphological structure of the fiber determines the pathway that dyes take during dyeing and is critical for the rate and extent of dye uptake. In some way, the dye has to penetrate the more or less hydrophobic layer on the fiber surface, formed by the epicuticle and the exocuticle. The strong swelling capacity of the intercellular cement is important for the penetration of dyes into the fiber. Only then are the sulfur-rich keratins also penetrated by the dye molecules. In general terms, Fick s law can be applied to the diffusion phenomena [46],... 

In addition to forming the chains of polyacrylate, the chains are cross-linked. This is a process in which two or more chains are held together by other compounds in a network. Typical cross-linkers for this polymer include di- and tri-acrylate esters. The swelling and elasticity of the polyacrylate polymer depends on the structure of this network and the number of cross-links. The swelling capacity of the polymer decreases with increased cross-link density. After formation, the polyacrylate is dried and formed into microparticles of irregular shape that can be stored for a long time. 

BPEI and LPEI were cross-linked with different dihalogen derivatives, formaldehyde, epichlorohydrin [55-73]. The cross-linking reaction allows to change the chemical and physical properties of the resins, e.g. the swelling capacity which is important for complex and adduct formation. Moreover, it is possible to vary the pore size which is also relevant in the ligand-metal complex formation. 

Shales. Shales are derivatives of clays, formed in slow diagenetic processes. Shales have little or negligible swelling capacity and have medium plasticity. They form effective aquicludes at thicknesses of at least a few meters to tens of meters. 

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