Ether polymers polyethylene oxide

Surfactants based on block copolymers of dimethylsiloxane with poly(ethylene oxide) are unique in regulating the cell size in polyurethane foams. One route to such polymers uses reaction I.E in Table 17.6 between a polysiloxane and an allyl ether of polyethylene oxide [11], Increasing the silicone content makes the surfactant more lipophilic (oil-loving), whereas increasing the poly(ethylene oxide) content makes it more hydrophilic (water-loving). 

Fluidized aqueous suspensions of 15% by weight or more of hydroxyethyl-cellulose, hydrophobically modified cellulose ether, hydrophobically modified hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, and polyethylene oxide are prepared by adding the polymer to a concentrated sodium formate solution containing xanthan gum as a stabilizer [278]. The xanthan gum is dissolved in water before sodium formate is added. Then the polymer is added to the solution to form a fluid suspension of the polymers. The polymer suspension can serve as an aqueous concentrate for further use. 

Nair and Chien [44] compared patches and tablets of different polymers (sodium carboxymethylcellulose, carbopol, polyethylene oxide, polymethyl vinyl ether-maleic anhydride, tragacanth) regarding their release characteristics of four drugs (chlorheximide, clotrimazole, benzocaine, and hydrocortisone). They observed sus-... 

Polymer phase-transfer catalysts (also referred to as triphase catalysts) are useful in bringing about reaction between a water-soluble reactant and a water-insoluble reactant [Akelah and Sherrington, 1983 Ford and Tomoi, 1984 Regen, 1979 Tomoi and Ford, 1988], Polymer phase transfer catalysts (usually insoluble) act as the meeting place for two immiscible reactants. For example, the reaction between sodium cyanide (aqueous phase) and 1-bromooctane (organic phase) proceeds at an accelerated rate in the presence of polymeric quaternary ammonium salts such as XXXIX [Regen, 1975, 1976]. Besides the ammonium salts, polymeric phosphonium salts, crown ethers and cryptates, polyethylene oxide), and quaternized polyethylenimine have been studied as phase-transfer catalysts [Hirao et al., 1978 Ishiwatari et al., 1980 Molinari et al., 1977 Tundo, 1978]. 

A. water. They include cellulose ethers, pregelatinized starches, polyethylene oxides, alginates, carrageenans, polyacrylamide, carboxyvinyl polymers and polyvinyl alcohol. 

Polymer Blends. The miscibility of polyethylene oxide) with a number of other polymers has been studied, eg, with poly(methyl methacrylate) (18—23), poly(vinyl acetate) (24—27), polyvinylpyrrolidinone (28), nylon (29), poly (vinyl alcohol) (30), phenoxy resins (31), cellulose (32), cellulose ethers (33), poly(vinyl chloride) (34), poly(lactic acid) (35), poly(hydroxybutyrate) (36), poly(acrylic acid) (37), polypropylene (38), and polyethylene (39). 

When equal amounts of solutions of polyethylene oxide) and poly(acrylic acid) are mixed, a precipitate, which appears to be an association product of the two polymers, forms immediately. This association reaction is influenced by hydrogen-ion concentration. Below ca pH 4, the complex precipitates from solution. Above ca pH 12, precipitation also occurs, but probably only poly (ethylene oxide) precipitates. If solution viscosity is used as an indication of the degree of association, it appears that association becomes more pronounced as the pH is reduced toward a lower limit of about four. The highest yield of insoluble complex usually occurs at an equimolar ratio of ether and carboxyl groups. Studies of the poly(ethylene oxide)—poly(methacrylic acid) complexes indicate a stoichiometric ratio of three monomeric units of ethylene oxide for each methacrylic acid unit. 

The polymers had molecular weights of several million, but were completely soluble in water and some organic solvents such as chloroform, acetonitrile, ethylene dichloride and acetic acid. The water solubility results apparently from strong hydrogen bonding between solvent and ether groups but appears to be peculiar to the polyethylene oxides for it is not observed with polyformaldehyde, polyacetaldehyde or poly-... 

Poly(methyl vinyl ether) [34465-52-6], because of its water solubility, continues to generate commercial interest. It is soluble in all proportions and exhibits a well-defined doud point of 33°C. Like other polybases, ie, polymers capable of accepting acidic protons, such as polyethylene oxide) and poly(vinyl pyrrolidone), each monomer unit can accept a proton in the presence of large anions, such as anionic surfactants, HI3, or polyacids, to form a wide variety of complexes. 

Polyethylene oxide). This ether-rich polymer (PEO) apparently forms hydrogen bonds with silanol groups, with concomitant adsorption of a PEO layer at silica surfaces. In the case of CZE, the fused silica capillaries are pretreated with 0.1 M NaOH and 0.1 M SDS at the beginning of each day. The typical coating protocol is to flush the capillary with 1.0 M HC1, followed by a solution of 0.2% PEO, then washing with an electrophoretic buffer. The coating process has to be repeated before each run. The EOF is reduced by 60-70%, and the columns thus treated work well for basic proteins. 

The most well-known member of this class is the polyether, polyethylene oxide, whose complexes with lithium perchlorate have been used commercially in lithium batteries.60-62 The good solvating power of polyethylene oxide is attributed to an optimal spacing of the electron-donating ether oxygens along a flexible backbone that allows multiple contacts between the polymer backbone and cations. When this distance is decreased, as in polymethylene oxide, chain flexibility is greatly reduced when it is increased, as in 1,3-polypropylene oxide, the distance between... 

The interfaces formed by evaporating copper, nickel and chromium layers on polystyrene, polyvinyl alcohol, polyethylene oxide, polyvinyl methyl ether, polyvinyl acetate and polymethyl methacrylate have been studied with X-ray photoemission spectroscopy (XPS). At submonolayer coverages of the metals, the peak positions and widths of the metallic electron core levels vary significantly from one polymer substrate to another. Most of... 

Nonionic ethoxylated surfactants and polyethylene oxide polymers have been found to adsorb on silica. The driving force for the adsorption of these reagents in considered to be hydrogen bonding between the ether... 

Two water-soluble polyethers, polyethylene oxide and polymethyl vinyl ether, were UV irradiated in hydrogen peroxide solutions. It was shown that hydroxy and hydroperoxy radicals accelerate oxidative degradation of these polymers. Hydroxy and probably hydroperoxy radicals can abstract hydrogen from methylene groups in both polymers. As a result of further oxidative reactions, different carbonyl, hydroxy and hydroperoxy groups are formed. A mechanism for the formation of these groups is proposed. 8 refs. 

Polar polymers require careful observation of their elution behaviour before the application of the hydrodynamic volume concept. Polyacrylonitrile (PAN) in a dimethylformamide (DMF)/lithium bromide (LiBr) solution at 60°C showed different elution behaviour to that of polyethylene oxide (PEO) and polyvinyl pyrrolidone, which means that for PAN the universal calibration method cannot be applied with PEO as standards [22]. On the other hand, copolymers of acrylonitrile and vinyl ether could be measured in a DMF/LiBr solution at 55°C [23]. Thus these SEC conditions were suitable for these copolymers using the universal calibration method. The Mark-Houwink equations were as follows ... 

Water retention Cellulose ethers, polyethylene oxide, vinyl polymers, and copolymers... 

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