Advantage, of polymers

Biospecific Chromatography Advantages of Polymer-Spacered Ligands 169... 

The advantages of polymer-supported reagents have been exploited for EGBs in the form of EGBs generated from polyacrylamides [74]. The effective base is in all cases an amide anion similar to (33) . 

The clean and efficient production of azo dyes is a classical chemistry problem. The manufacture of this industrially important family of compounds is traditionally associated with the additional formation of large quantities of hazardous and colored waste. A method for the construction of both phenolic and amino azodyes has been reported using a polymer-supported nitrite reagent to effect diazoti-zation of aromatic amines (Scheme 2.53) [80]. Waste minimization and operational simplicity, along with improved separation technologies, are key advantages of polymer-supported reagents in this area. 

Note 1 The easy separation of low-molar-mass reactants or products from the polymer-supported species is a great advantage of polymer-supported reactions. 

Amylose brushes (a layer consisting of polymer chains dangling in a solvent with one end attached to a surface is frequently referred to as a polymer brush) on spherical and planar surfaces can have several advantageous uses, such as detoxification of surfaces etc. The modification of surfaces with thin polymer films is widely used to tailor surface properties such as wettability, biocompatibility, corrosion resistance, and friction [142-144]. The advantage of polymer brushes over other surface modification methods like self-assembled monolayers is their mechanical and chemical robustness, coupled with a high degree of synthetic flexibility towards the introduction of a variety of functional groups. 

An advantage of polymer-based reagents is that both the excess and the spent reagent are easily separated from the product. Bruno Linclau of the University of Southampton has reported J. Org. Client. 2004, 69,5897) the preparation of a polymer-bound carbodiimide. Exposure of the polymer to alcohol gives a family of O-alkylisoureas that smoothly convert carboxylic acids to the corresponding esters. Methyl, benzyl, ally and p-nitrobenzyl transfer smoothly. The polymeric (-butyl reagent could not be prepared. 

Polymer bound Schiff s bases are receiving increasing attention, as these materials are expected to combine the selective properties of low molecular weight Schiff s base chelates with the advantage of polymer immobilization. Wohrle et al. [7] synthesized a copolymer of 2-butylimino-4-vinylphenol with S to prepare O-chelates [7]. 

Disadvantages. The discussion of the advantages of polymer adsorption was relative to solvent extraction. This same perspective will be used in the discussion of the disadvantages. Most analytical chemists are familiar with solvent extraction procedures using solvents that are readily available in the desired purity. When the solvents are not pure enough for direct use in trace analytical work, the purification procedures are usually ones that are familiar to most bench chemists and technicians. These advantages of solvent extraction are the disadvantages of polymer adsorption. 

Table n. Potential Advantages of Polymer Electro-optic Materials... 

An advantage of polymers is the well developed knowledge in polymer science. It is a mature technology and is compatible to other materials. Methods to produce various shapes and to structure elements are established. Specific procedures to change the mechanical or thermal properties are known. 

The advantage of polymer supports for organic synthesis may have different causes ... 

All the advantages of polymer supports are in principal fulfilled even if we use linear polymers (M — 104—10s). This enables working in a homogeneous phase but there... 

Doping unsublimed and sublimed stacked [Al(F)Pc] and [Ga(F)Pc] under various conditions with iodine leads to organic solids of high conductivity (Table 10) The Raman spectra show that (tojmg results in the reduction of iodii% to Jf. It is disadvantageous, that these polymers evolved iodine when stored at T = 300 K. Moreover, the iodine doped (67) is indefinitely stable in air J2 may be removed by heating above 373 K. Hie advantage of polymer (79) is the possibility to prepare thin films by sublimation. 

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