Copper-Polymer Systems

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

In case of copper some rheological experiments carried out at a given polymer concentration and increasing amoimt of cations indicates that copper/pectin systems in the one-phase domain behave as a viscoelastic liquid rather than a viscoelastic solid referred to as true gel (G (co) = G, when to—>0 with Gg the equilibrium shear modulus)[35]. Despite the lack of experimental data the range in cation and polymer concentration in which true gels may be observed seemed very limited. These results corroborate the strength of the binding of copper by pectins evidenced by the properties of the phase separation curves. 

They next studied the asymmetric oxidative polymerization of achiral 2,3-dihydroxynaphthalene (Scheme 42). The polymerization of this monomer with CuCl2-(-)-sparteine complex resulted in a low yield and gave a low molecular weight oligomer, whereas the polymerization with CuCl-(S)-Phbox quantitatively gave a polymer with Mn of 10 600-15 300. The enantioselectiv-ity attained in this polymerization, however, was estimated to be low, with 43% ee from the model reaction [169]. When vanadyl sulfate (VOSO -Phbox complex was used instead of the copper catalyst system, the enantioselectivity was improved up to 80% ee [170]. Asymmetric cross-coupling polymerization of two kinds of naphthol derivatives was also reported [171,172]. 

Some redox systems have been developed for certain polymers. The copper/iodine system is well established for polyamide thermal stabilization, and in spite of introducing a heavy metal ion into the polymer, works well in an oxygen-free environment.83 84... 

The main advantages of the photo-polymer system include safer operations that do not use hot metals, such as zinc or magnesium, or plating solutions for the deposition of copper. Processing involves the use of developers such as water, dilute sodium hydroxide, and dilute solutions of sodium carbonate. Because each plate is a copy of the original (not a duplicate from a mould that has been used many times) the print quality is consistent and more predictable. While some of the pressures for change were environmental a bonus is that the overall costs of producing photo-polymer plates are lower than those for the traditional metal plates. 

Methanol is a good solvent for HEMA and its polymer, and thus can be employed for its homogeneous living radical polymerization with Ru-3, which is also highly soluble in methanol.59 Copper-based systems also give homogeneous living radical polymerizations of HEMA in a mixture of methyl ethyl ketone and 1-propanol,243 of acrylamides in methanol,117172 and of 4-vinylpyridine (M-33) in 2-pro-panol.214... 

Amino- and amido-functionalized monomers can also be polymerized directly with metal catalysts. Living radical polymerization of 2-(dimethylamino)-ethyl methacrylate (FM-5) was achieved with 1-31 (X = Br)/CuBr/L-29 in dichlorobenzene at 50 °C.314 Its ammonium salt (FM-6) was polymerized from the surface of a cross-linked polystyrene latex with CuBr/ L-l in water at 80 °C to generate hydrophilic shells, although there were no data for polymer molecular weight.248 As described above (section II.C.6), (methacrylamides with at least their amido protons unprotected (FM-7, FM-8, and FM-9) can be polymerized with copper-based systems,117168,217,218 but a further optimization seems to be necessary. 

Miscellaneous Extrusion-Applied Polymers. As mentioned earlier, there is a tendency to develop solventless magnet wire enamel formulations, and extrudable polymer systems would fulfill that requirement. There have been reports about extrusion of thin coatings of polyesters over copper wire. At this point, the state of the art allows extrusion of thin insulating films only with thermoplastic materials. The reliable extrusion of uniform and concentric insulating films of approximately 0.001-0.002 in. wall thickness is already an improvement over the more traditional extrusions of polyethylene, poly(vinyl chloride), and several fluoropolymers in much greater wall thicknesses. Because cross-linked insulation is ultimately required for most magnet wire applications, further materials development needs to be done to provide polymer compositions that are both extrudable as thin films and can be cross-linked in an economical process suitable for large-scale industrial application. 

Morgan, L, W., Goodwin, K. V., Pennington, W. T, and Petersen, J. D., Synthesis and structure of infinite-chain copper(ll) polymer systems, Inorg. Chem., 31, 1103-1106 (1992). 

Cationic contaminants may emanate from many sources. Metals, such as iron and copper, in system components may ionize due to corrosion exchange with protons in the membrane. Metallic salts, such as sodium and calcium, may enter the fuel cell from coastal water or from deicing agents. The most likely source of cationic contaminants is from the fuel line. Hydrogen from reformed hydrocarbons usually contain parts per million (ppm) of ammonia. This ammonia can be oxidized to ammonium ions and enter the polymer electrolyte. 

Recently light-sensitive polymers were applied in two-phase polymer systems (Li et al, 2010). A light-sensitive polymer was synthesised by copolymerisation of A-isopropylacrylamide (a temperature-responsive monomer) with rV-vinyl-2-pyrrolidone and chlorophyUin sodium copper salt (light-sensitive monomers) (Wang et al., 2008). The polymer was used in a two-phase polymer system for the separation of protein (BSA) and amino acid (L-Tyr). The conformational change of the copolymer was induced by light applying laser radiation at 488 nm. About 98% of the copolymer was recovered after the separation. 

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