Phase polyvinylpyrrolidone - water

The purpose of this study is twofold to compare four linear aqueous SEC columns made by Tosoh and Showa Denko in terms of composition and performance and to evaluate the effect of commercial PEO standards on the accuracy and precision of the MW and MWD of polyvinylpyrrolidone (PVP) and NIST PEO standards. In terms of performance, emphasis will be placed on factors not commonly covered by column manufacturers. Successful SEC conditions for PVP in water, in water/methanol, and in dimethylformamide can be found in the literature (8,9,10). This study deals mainly with the effects of column, mobile phase, and PEO standards on the MW and MWD of PVP. 

It is surprising to note that for all four columns there is good agreement between the M determined in water and in water/methanol, despite the fact that PEO and polyvinylpyrrolidone have different hydrodynamic volumes in these two mobile phases and that the column packings may swell or shrink differently in these two mobile phases. 

Fig. 1.17.2. Phase diagram for polyvinylpyrrolidone (PVP)-water. For 80 exlanations, see Figure 1.17.1 (Figure 4 from [1.14])...

Dobry and Boyer-Kawenoki (1948) showed that phase separation occurs in mixed solutions of many water-soluble polymers such as gelatin, serum albumin, gum arabic, glycogen, polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, polyacrylic acid, and so on. They have shown that immiscibility or limited co-solubility is typical of all polymers. The theory of the thermodynamic incompatibility of polymers was devel-... 

After completion of phase inversion, the polymer solution is dispersed in a 2-4-fold amount of water. Suspension aids used are water-soluble organic polymers, such as poly(vinyl alcohol) or polyvinylpyrrolidone, or inorganic compounds, such as Pickering systems. In order to achieve a final conversion of 99.5 %, initiator combinations with different decomposition times are used, and the polymerization follows a defined temperature-time profile. The suspension is then centrifuged, dried and compounded. 

The Interaction of water soluble polymers with microemulsions and with surfactants will, when the components are sufficiently concentrated, often result in a phase separation or change in the phase boundaries of the mixture as a function of external variables, such as temperature or salinity. In order to arrive at a better understanding of this technologically Important phenomenon, a series of experimental studies was carried out using a variety of water soluble polymers in conjunction with model mlcroemulslon systems. The polymers used Included polyethylene oxide, polyvinylpyrrolidone, dextran, xanthan, polyacrylamide, and hydrolyzed... 

Typical stationary phases include the following polyvinylpyrrolidone (PVP) coated silica sorbents, monodisperse non-porous silica columns with surface bound amides or ethers and composite agarose and polyacrylamide gels. The eluent normally consists of salts at concentrations greater than 1.0 M. Typical salts include sodium phosphate, sodium sulfate and ammonium sulfate, and organic acid salts like monosodium glutamate. Protein retention is stronger with salts that increase surface tension like phosphates, sulfates, citrates, which are solvated in water than with salts such as perchlorates and thiocyanates and the like. 

Many methods are available for removal of organic material from aqueous samples by off-line SPE [7]. Hydrophobic organic material is best extracted by solid poly(sty-rene-DVB) polymers or reversed-phase silica extractants. Polyvinylpyrrolidone (PVP) is an appropriate choice for removal of humic acids, lignins and tannins from water samples. 

High-molecular mass surfactants such as butyl acrylate-butyl methacrylate-methacrylic acid copolymer sodium salts, starburst dendrimers, poly(amidoamines), and diaminobutane-based poly(propyleneimine) as well as cationic polyelectrolytes (ionenes) had all been presented as successful secondary phases for aromatic compounds. The determination of 10 nitrophenols in glycine buffers modified by 3-CD (0-10 mmolL" ) and polyvinylpyrrolidone (PVP) (0.5-2.5% w/v) is an example of application of polymer-based electrolytes to rain, tap, and process water. ... 

F01 Foroutan, M. and Khomami, M.H., Activities of polymer, salt and water in liqttid-liqttid eqttilibria of polyvinylpyrrolidone and K2HPOVKH2PO4 buffer using the Flory-Huggins model with Debye-Hueckel equation and the osmotic virial model Effects of pH and temperature. Fluid Phase Equil., 265, 17, 2008. 

It was therefore to be exacted that the antidpated thermolysis products would not be separable on silica gel using a single solvent system. In all, 4 mobile phases were used for the thermolysis products, which sometimes showed tare fluctuations in polarity (cf. Table 21). As expected, the fatty add components were formed in the TFG of polyvinyl esters (cf. Fig. 24 and Table 21). These can be separated relatively well using acetone-n-butanol-2S%ammonia-water (65 + 20 + 10 + S), at chamber saturation and in a run of 15 cm (cf. Fig. 24 and Table 21). Polyacrylates and polymethacrylates yield the corresponding monomers which can be separated satisfactorily with n-heptane-chloroform (50 + 50) (cf. Figs. 25 and 26). The fairly unpolar binary mixture of n-hexane-toluene (50 + 50) separates the breakdown products of polyvinylcarbazole (cf. Figs. 27 and 28, and Table 21). In contrast, the more polar fission products of polyvinylpyrrolidone need the more polar mobile phase of chloro-form-ethylacetate (70 + 30) to obtain adequate hRf-differences. Reference may be made to Table 21 below for information about detection of the various thermolysis products. 

Within this project aqueous solutions of Polyvinylpyrrolidone (PVP) were atomized using the C02-assisted atomization process. Phase equilibria data of these aqueous solutions and CO2 were not known at the beginning of this project. Hence, it was necessary to measure these data for selected temperatures and pressures. In Fig. 7.7, the trend of the solubility of CO2 in aqueous PVP (30 wt.% PVP) solutions compared to the solubility of CO2 in pure water is shown. The system of water, PVP, and CO2 is assumed as pseudo binary, where the aqueous PVP solution represents one component and CO2 is the second component. 

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