Sorption and partial molar volumes of gases in poly(ethylene‐co‐vinyl acetate)

Abstract

SYNOPSISSorption and dilation properties of polymer-gas systems involving poly (ethylene-co-vinyl acetate) and N2, CHI, or C 0 2 , have been investigated at pressures up to 50 atm at temperatures of 10-40"C. Sorption isotherms for low-solubility gases (i-e., CH, and N2) can be described by Henry's law, and those for high-solubility gas (i.e., C O P ) by Flory-Huggins dissolution equation. Dilation isotherms are similar in contour to the corresponding sorption isotherms. From the obtained sorption and dilation data, partial molar volumes of the gases in the polymer were determined as a function of temperature. Thermal expansivity of dissolved C 0 2 molecules was estimated at ca. 2.4 X O C -' from the temperature dependence of partial molar volume. The expansivity is smaller than that of liquid COz and larger than those of the polymer and organic liquids. 0 1994 John Wiley & Sons, Inc. Keywords: poly (ethylene-co-vinyl acetate), gas sorption in dilation of poly( ethyleneco-vinyl acetate) due to gas sorption * partial molar volume of dissolved gases * thermal expansivity of dissolved gas * On leave from Pechiney Emballage Alimentaire, 92115 Clichy, France. CCC 0887-6266f94 fO2028l-06 estimated. The result is discussed and compared with the expansivities of liquid C 0 2 , organic liquids, and C02 molecules dissolved in other polymers.

Carbon dioxide-poly(vinylidene fluoride) interactions at high pressure

“…Kamiya et al 31 have shown that for low pressure (up to 6 MPa) for gases which follow the Henry's law sorption model (linear relationship between the concentration of the gas and the pressure), the plot of (1 ϩ ᐉ s ) 3 (1 ϩ K t ⅐ P) as a function of C is a straight line. As is shown on Figure 4 and Figure 6, above 6 MPa, the Henry's law cannot be applied.…”

Solubility and partial molar volume of carbon dioxide and ethane in crosslinked poly(ethylene oxide) copolymer

“…Upon combining sorption and dilation data for a given polymer‐penetrant pair, one can estimate the partial molar volume (PMV) of the gas in the polymer, V . When polymer compression effects can be neglected, which is reasonable for XLPEO materials and the gases considered in this work under the adopted operating conditions,22 V is computed as follows:49 …”

“…To take this dependence into account, the PMV of a dissolved gas in different materials, either liquids or polymers, at a given temperature, ought to be compared as a function of the solubility parameter (δ) of the solvents. Therefore, in Figure 10 our values for the PMV of carbon dioxide and ethane in the XLPEO copolymer at 25 °C, computed from eq 15, are compared with literature data for different liquids53–65 and rubbery polymers,47–50, 66–72 all of which plotted as a function of the solubility parameter of the solvent. Solubility parameters were taken from the literature,37, 73, 74 apart from the value related to the XLPEO copolymer, which was estimated by the relation between the solubility parameters and the Flory‐Huggins interaction parameter for a given polymer‐penetrant pair:75 where δ p and δ g are the solubility parameters of the polymer and the gas, respectively.…”

“… Comparison of partial molar volumes of carbon dioxide and ethane in the XLPEO copolymer (PEGMEA70) at 25 °C with literature data for liquids and rubbery polymers as a function of the solubility parameter of the solvent. Data for CO 2 were taken from Horiuti53 (acetone, methyl acetate, benzene, chlorobenzene, carbon tetrachloride), Hildebrand and Scott54 (methanol), Weiss59 (water), Moore et al60 (water), Kamiya et al62 (PDMS), Xu et al63 (propylene carbonate, methyl cyanoacetate, n ‐formyl morpholine), Cibulka and Heintz64 ( n ‐hexane, n ‐heptane, n ‐octane, n ‐decane, n ‐hexadecane, ethanol, 1‐propanol, 1‐butanol, 1‐octanol, 1‐decanol), Ashcroft and Isa65 ( n ‐heptane, n ‐octane, n ‐nonane, n ‐decane, n ‐dodecane, n ‐tetradecane, n ‐hexadecane, cyclohexane, methylcyclohexane, toluene), Hirose et al47 (low‐density polyethylene), Kamiya et al48–50 [poly(1,2‐butadiene), poly(ethylene‐ co ‐vinyl acetate), poly(dimethyl siloxane)], and Wang et al70 [poly(benzyl methacrylate)]. Data for ethane were taken from Horiuti53 (acetone, chlorobenzene, methyl acetate), Gjaldbaek and Hildebrand55 (perfluoroheptane, carbon disulfide, carbon tetrachloride, n ‐hexane, benzene), Hildebrand and Scott54 (acetone, methyl acetate, carbon tetrachloride, benzene, chlorobenzene), Masterton56 (water), Ng and Walkley57 ( n ‐hexane, benzene), Tiepel and Gubbins58 (water), Handa et al61 ( n ‐octane, methanol, ethanol, 1‐butanol, 1‐hexanol, 1‐octanol, 1‐decanol), and Kamiya et al48, 50, 72 [low density polyethylene, poly(1,2‐butadiene), poly(ethylene‐ co ‐vinyl acetate), poly(dimethyl siloxane)].…”

Sorption of CO2 in Shales Using the Manometric Set-up

“…The partial molar volume describes the increase in volume of the sorbing medium when a mole of CO 2 is sorbed on it. The density ρ a = 264 kg/m 3 obtained for sorption on shale is very small with respect to equivalent densities when CO 2 dissolves in water or brine (Carrol and Mather, 1992;Enick and Klara, 2009;Parkinson and Nevers, 1969) or in ionic melts (Huang et al, 2005;Kumelan et al, 2009;Duncan and Agee, 2011;Jalili et al, 2010) or sorbs on polymers Kamiya et al, 1994). Therefore an explanation in terms of a sorbed phase density must be critically evaluated.…”