Polymeric complexing agents

The complexation properties of PEI were investigated in the aqueous phase for Co, Ni, Zn, Cd, and Cu ions using membrane filtration [35, 39, 40]. According to the elution behavior, which was measured for each metal at different pH values, PEI is an effective polymeric complexing agent suitable for the retention and separation of metals in aqueous diluted solutions. 

TaUe 5. Some examples of soluble polymeric complexing agents... 

This chapter reviews the main results obtained in the fields of starch-filled plastics and thermoplastic starch with particular attention to the concept of gelatinisation, destructurisation, extrusion cooking, and the complexation of amylose by means of polymeric complexing agents with the formation of specific supra-molecular structures. The behaviours of products now in the market are considered in terms of processability, physical-chemical and physical-mechanical properties and biodegradation rates. 

Protein adsorption has been studied with a variety of techniques such as ellipsome-try [107,108], ESCA [109], surface forces measurements [102], total internal reflection fluorescence (TIRE) [103,110], electron microscopy [111], and electrokinetic measurement of latex particles [112,113] and capillaries [114], The TIRE technique has recently been adapted to observe surface diffusion [106] and orientation [IIS] in adsorbed layers. These experiments point toward the significant influence of the protein-surface interaction on the adsorption characteristics [105,108,110]. A very important interaction is due to the hydrophobic interaction between parts of the protein and polymeric surfaces [18], although often electrostatic interactions are also influential [ 116]. Protein desorption can be affected by altering the pH [117] or by the introduction of a complexing agent [118]. 

Polymerization and depolymerization of sihcate anions and their interactions with other ions and complexing agents are of great interest in sol—gel and catalyst manufacture, detergency, oil and gas production, waste management, and limnology (45—50). The complex silanol condensation process may be represented empirically by... 

Cosolvents ana Surfactants Many nonvolatile polar substances cannot be dissolved at moderate temperatures in nonpolar fluids such as CO9. Cosolvents (also called entrainers, modifiers, moderators) such as alcohols and acetone have been added to fluids to raise the solvent strength. The addition of only 2 mol % of the complexing agent tri-/i-butyl phosphate (TBP) to CO9 increases the solubility ofnydro-quinone by a factor of 250 due to Lewis acid-base interactions. Veiy recently, surfac tants have been used to form reverse micelles, microemulsions, and polymeric latexes in SCFs including CO9. These organized molecular assemblies can dissolve hydrophilic solutes and ionic species such as amino acids and even proteins. Examples of surfactant tails which interact favorably with CO9 include fluoroethers, fluoroacrylates, fluoroalkanes, propylene oxides, and siloxanes. 

The mid-block monomers are primarily isoprene and butadiene. These diolefins can polymerize in several ways. The isomeric structure of the final polymer has a strong impact on its properties and thermal stability. Isomeric composition is easily varied by changing the polymerization solvent or adding complexing agents. The typical isomeric structures for isoprene and butadiene mid-blocks are shown in Fig. 2. 

Solvent polymeric membranes, conventionally prepared from a polymer that is highly plasticized with lipophilic organic esters or ethers, are the scope of the present chapter. Such membranes commonly contain various constituents such as an ionophore (or ion carrier), a highly selective complexing agent, and ionic additives (ion exchangers and lipophilic salts). The variety and chemical versatility of the available membrane components allow one to tune the membrane properties, ensuring the desired analytical characteristics. 

As yet there have been no reports that the actinides in the biosphere become complexed in a chemical form which would facilitate their transport through the food chain to man. All the available evidence indicates that solutions of the actinides hydrolyze to give polymeric forms which exhibit limited mobility in cellular systems. There are, however, many complexing agents in the biosphere which could form stable complexes with the actinides, such complexes could alter the transport of the actinides in microenvironments but these microenvironments have yet to be identified. 

Wang GM, van Beylen M (2003) Influence of 7t-complexing agents on the anionic polymerization of styrene with lithium as counterion in cyclohexane. 1. Effect of durene. Polymer 44 6205-6210... 

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