Reduction polymers

The addition of an electron-accepting material, such as iodine, to a polymer is known as oxidative doping because electrons are lost from the polymer. Reductive doping is the process by which an electron-donating material, such as sodium, is added to a polymer. In this case, the polymer gains an electron and becomes negatively charged. 

The deposition of metals such as Pd, Pt, Ni, and Cu renders the surface active towards further metal deposition from conventional electroless metal plating baths. Well-adhering metal films can be formed on polyimides by this method. The main process steps for blanket metallization of a polyimide film, illustrated in Scheme I, involve polymer reduction, metal seeding, and electroless metal plating. Specific details of each process step are provided in the discussion below. 

A polymer/monomer (polymer/repeat-unit or polymer/macrocycle) switch may become of practical importance where a polymer decorated with certain groups has specific size-dependent properties that the monomeric units do not have. The modulation of the conversion between polymeric and monomeric (or macrocyclic) states would also result in the modulation of these properties. Moreover, such size switches, represented by polymerization/depolymerization processes that operate under the control of external events, are examples of environmentally-friendly recyclable polymers (reduction of waste treatment). As well, if the polymer has low solubility and the polymer/monomer switch can work in spite of this, then it becomes possible to reversibly generate a precipitating (solid) polymeric material from a liquid solution of monomer. 

Condensations of pyrroles with aldehydes and ketones oceur easily by acid catalysis, but the resulting pyrrolyl-carbinols cannot usually be isolated, for under the reaction conditions proton-catalysed loss of water produces 2-alkylidene-pyrrolium cations that are themselves reactive electrophiles. Thus, in the case of pyrrole itself, reaction with aliphatic aldehydes in acid inevitably leads to resins, probably linear polymers. Reductive trapping of these cationic intermediates, producing alkylated pyrroles, can be synthetically useful, however all free positions react acyl and alkoxycarbonyl-substituents are unaffected. ... 

Polymer Reduction Due to HjO Comeminant PcHi Reduction Due to HjO Contaminant fV/PcH Reduction Due to HjO COntaminem... 

A reasonable interpretation is that when the concentration of a monomer or reactant is initially greater than 2wt% in an exempt polymer, the concentration may be lowered to less than or equal to 2 wt%, but not zero, to satisfy the exemption for the same polymer. Reduction of the concentration to 2wt% or less seems to be allowed because the guideline does not say otherwise. 

Quartz crystal microbalance studies have shown that the movement of the solvent molecules associated with ions can be considerable. Using PPy prepared in sodium dodecyl sulfate, a mix of both cation- and anion-driven processes was seen when cycled in NaCl, and the mass changes involved indicated that four water molecules moved per Cl and 15 water molecules per Na" " [11]. The role of solvent water molecules has also been examined for PPy in dodecyl benzene sulfonate (DBS), a very widely studied system, where the insertion of cations accounted for only 20% of the mass change upon polymer reduction, indicating that four water molecules were brought into the film with each Na+ [12]. As the electrolyte concentration was changed from 0.1 M to 6 M, the total inserted mass became smaller and the mechanism moved from pure cation transport to an equal amount of anion transport [13]. These results were said to support an osmotic expansion model, whereby the difference in osmotic pressure between the electrolyte and polymer bulk (greater with more dilute electrolyte solutions) drives solvent movement. 

The self-healing effect, described in this section, is in our opinion an extension of the ennobling mechanism in which the release of anions, concomitant to polymer reduction, is used in order to control to some extent the electrolytic medium around the scratch and thus facilitate its passivation. Studies in this direction are stiU scarce and further work is needed to explore this concept. Some of the work described in Section 16.2.2 probably concerns self-healing properties, but this concept was not highhghted by the authors. It should be reanalysed in the light of recent work more focused on self-healing effects. 

Polymer Reduction Due to H2O Contaminant PcKi Reduction Due to H2O Contaminant CH. Reduction Due to H2O Contaminant... 

Therefore, there is a considerable interest in replacing some or all of the synthetic plastics by natural or biodegradable materials in many applications. Since the food industry uses many plastics, even a small reduction in the amount of materials used for each package would result in a significant polymer reduction, and may improve solid waste problems [10]. It is clear that the use of biodegradable polymers for packaging offers an alternative and partial solution to the problem of gathering of solid waste composed of synthetic inert polymers [11]. 

Several examples of polymer-polymer incompatibility in aqueous solution are given in Reference 3, whereas de Hek and Vrij (4) recently described a phase separation in a solvent in which both polymer and colloidal spheres were dissolved. Ph se separation can be suppressed by reducing the molecular weight of the polymers. Reduction of the salinity reduces the size of the surfactant micelles and indeed also the polymer-surfactant incompatibilities (5,6). Actually, reduction of the salinity of the polymer drive, even without direct reference to polymer/surfactant incompatibilities, has recently become a favorable recipe for successful micellar floods (7-9). 

Polymer Reduction Due to H 0 Contaminant Pctu Reduction Due to H 0 Contaminant PttJPau Reduction Due to H 0 Contaminant... 

Different organic local modificatimi, e.g., diazonium attachment, polymer reduction, and thiol desorption, have been demonstrated and studied [82, 97-106]. Local oxidation or desorption of self-assembled mmiolayers was followed by local deposition or specific attachment onto the modified patterns [ 105,106]. The reduction of polymer, such as PTFE, made it possible to locally metalize or further polymerize the reducing sites [101-104]. More recently, a few approaches have been developed for the formation of either an anisotropic structure using a non-disk-shaped nricroelectrode and imprinting its structure [107] or by constructing... 

The spontaneous formation of Au particles at room temperature in air-saturated aqueous solutions of poly(ethylene glycol)s was investigated using optical, potentiometric and conductivity techniques. The kinetic information is consistent with a mechanism in which Au(III) complexes bind through ion-pairs to pseudocrown ether structures of the polymers. Reduction of the metal centers follows through their reactions with the oxyethylene groups that form these cavities. The particle size of the metal crystallites is controlled by the molar mass of the polymers. Agglomerates of small Au particles are formed as final products when polymers of low molar mass are used in the synthesis. 

Agrawal and Jenekhe [1102] reported the electrochemistry and UV-vis spectroscopy of a series of conjugated polyquinolines and polyanthrazolines with systematically varied substituents. The good agreement between the value of the bandgap energy as derived from UV-vis spectroscopy and as derived from electrochemical data (electrode potential of polymer reduction and oxidation) is noteworthy. Despite the fact that such a correlation is logical, experimental support is scant. 

In Example 5,8, the incremental oil recovered as a result of the irtjection of a polymer slug (0.424 PV) was found to be 27,658 STB at tp, =0.8079, corresponding to arrival of the polymer slug at the end of the system. When the polymer slug is reduced to 0.212 PV, as in Example 5.10, cumulative oil production is estimated to be 132,625 STB at =0.8079. Incremental oil above the waterflood is 15,739 STB for an oil/polymer ratio of 1.49 STB/lbm of polymer. Reduction of the size of the polymer slug reduces the cost of polymer and the incremental oil recovery. If economic parameters were known, it would be possible to determine an optimum slug size by conducting a series of these calculations. 

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