Polymers dual-function

Every water treatment service company has several dual-function or multifunction programs in their BW product range based on chelant, phosphate, or polymer. Which of these particular chemistries takes the lead position depends on the type of waterside problems likely to be encountered (in some ways this is related to the particular market sector) and the positioning of the company within the overall BW treatment marketplace. 

Peterson DS, Rohr T, Svec FK, Frechet JMJ (2003) Dual-function microanalyt-ical device by in situ photolithographic grafting of porous polymer monolith integrating solid-phase extraction and enzymatic digestion for peptide mass mapping. Anal Chem 75 5328... 

To improve chromatographic separation, another analytical column could be used in addition to the monolith (Xu et al. 2006). The monolith column served as an extraction column only. Hsieh et al. (2000, 2002) utilized a polymer-coated mixed function (PCMF) Capcell C8 column (4.6 x 50 mm, Phenomenex) to provide dual functions—online plasma extraction and analyte separation. The silica was coated with a polymer containing both hydrophilic polyoxythylene and hydrophobic groups. The diluted plasma samples (1 1 to 1 3) were injected directly. No column deterioration was observed after 200 injections. 

Dual-Function Polymer Device and Display Matrices. 18... 

G Yu, C Zhang, and AJ Heeger, Dual-function semiconducting polymer devices light-emitting and photodetecting diodes, Appl. Phys. Lett., 64 1540-1542, 1994. 

AJ Heeger and G Yu, Dual Function Conducting Polymer Diodes, U.S. Patent 5,504,323, 1996. 

Multifunctional monomers, such as acrylates (e.g., TMPTA), were found to have a dual function to enhance the copolymerization and to cross-link the grafted trunk polymer chains. An addition of an acid along with a polyfunctional monomer has synergistic effects on grafting. ... 

Binder. The binder of a composite solid propellant serves the dual function of providing a matrix to hold the oxidizer and the metal fuel, and of serving as a fuel itself—although its total makeup in modem formulations may only be 8-10 wt percent. The binder of the propellant usually is considered to consist of the polymer, the curing agent, and the plasticizer—and can arguably include soluble stabilizers, as well. 

The available data concerning the effect of metal compounds on the pyrolysis and combustion of polymeric materials show that there is a great potential in the control of these materials, This field is still in its embryonic stage. Much is yet unclear. In many cases the analysis is rendered difficult because of the dual function of metal compounds (especially of the d- and f-types) in redox reactions. Their ability not only to inhibit but also to promote polymer decomposition manifests itself most clearly in concentration effects The specific effects of certain metal compounds on the ignition and combustion rate of polymers indicate that heterogeneous oxidation... 

In contrast with the usually slow progress of condensation polymerization the second major classification, addition, or vinyl-type polymerizations, usually proceed very rapidly, so rapidly that they are referred to as chain reaction polymerizations. This method of producing synthetic polymers uses the potential dual functionality present in a carbon-carbon double bond. The process is initiated by the use of radical or charged initiator species to form new sigma bonds from the carbon-carbon double bonds of the monomer, to link the monomer units (Eq. 20.6). 

Pd complex-catalyzed copolymerization of alkene and CO affords the polyketones via alternating insertion of the two monomers [166, 167]. The polymer growth involves migratory insertion of CO into the metal-carbon bond as a crucial step, which is unique to the late transition metal complexes such as Ni, Pd, Rh, and Co. The copolymerization of allenes and methylenecydopropanes with CO has attracted much less attention than the alkene-CO copolymerization, although it would provide further functionalized polyketones due to the dual functionality of the dienes and the derivatives. 

Peterson, D.S. Rohr, T. Svec, F. Frechet, J.M.J. Dual-function Microanalyti-cal Device by In Situ Photolithographic Grafting of Porous Polymer Monolith Integrating Solid-Phase Extraction and Enzymatic Digestion for Peptide Mass Mapping, Anal. Chem. 75, 5328-5335 (2003). 

The PEM, which is a key component of the PEMFC, has dual functions of (i) conducting the protons and (ii) separating the anode and cathode chambers. The PEM is also critically important with regards to the performance and cost of a PEMFC. In this chapter, attention is focused on the main issues and progress in polymer and hybrid materials for PEMFC applications. 

It is concluded that the incorporation of a small amount of alkali or alkaline earth oxide, V20g, amphoteric oxide, or oxide of heavy metal into silica gel induces a marked increase in the activity. This finding suggests that the proton-abstraction from a methyl group of acetaldehyde can be promoted by active sites with a relatively weak base, arising from V2O5 and amphoteric oxides. On the other hand, the formation of acrolein is accompanied by two sides reactions (1) formation of CO2 and methanol by Equations (4) and (5) which is promoted mainly by acid-base dual functions, and (2) polymerization of acrolein to unidentified polymers, which is promoted by strongly acidic sites. 

A series of quantitative data for solvent effect on the aminolysis of nitrophenyl esters attached to polyacrylamides have also been reported [41b]. These data are in broad agreement with the above-mentioned observations. However, the apparent solvent effects in chemical transformation of polymers must be interpreted in terms of a dual function, i.e. polymer solvation and solvent catalysis . For example, DMSO is a poor solvent for copol3 AOTq)-styrene), but a good solvent for polymers carrying amide residues. It should also be noted that alcohols and water are not usually suitable as solvent for chemical transformation of activated esters, because they may them lves enter the reaction as nucleophiles. 

The balance of the many possible interactions in these MHAP produces unique rheological behavior (20-24, 27). Thus, the surfactant in the MHAP is an integral component of the polymer-surfactant system, serving a dual function of aiding the formation of the polymer architecture during polymerization as well as being reversible cross-link points in solution. 

Since the mediators should be mobile in order to provide the electron flow between the enzyme catalytic centre and electrode, they are usually soluble in the electrolytic medium, and therefore could be lost during the repetitive measurements. This, in combination with inactivation of enzyme, due to its denaturing leads to the loss of sensitivity of the biosensor with time. The possible solution to this problem is using an excess of enzyme and mediators in the measurement. Recendy, a new technique has been developed where redox polymers were used in dual function as immobilisation matrix and as materials facilitating electron-transfer. In materials such as these, the mediator redox... 

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