Sorption, Dilation, and Partial Molar Volumes of Carbon Dioxide and Ethane in Cross-Linked Poly(ethylene oxide)

Abstract

Experimental gas solubility and sorptive dilation data are reported for carbon dioxide and ethane in a cross-linked poly(ethylene oxide) rubber prepared by photopolymerization of poly(ethlyene glycol)diacrylate. Five different operating temperatures (253 e T (K) e 308) were considered, with a maximum gas pressure of 2.16 MPa (21.3 atm). The importance of taking sorptive dilation into account in the determination of gas solubility in polymers by the pressure-decay method was demonstrated. Sorption isotherms in terms of gas fugacity were described by the Flory-Huggins model. In the case of ethane, the Flory-Huggins interaction parameter was a decreasing function of temperature. In contrast, for carbon dioxide, a single parameter represented all isotherms. Dilation and sorption data were combined to calculate the partial molar volume (PMV) of the gases in the polymer, which was an increasing function of temperature. The PMV data were compared to the available literature data for other rubbery polymers and liquids. The chemical structure of the polymer influenced the PMV of the sorbed gas, and a correlation between matrix (i.e., solvent or polymer) solubility parameter and PMV was found.

Partial Molar Volumes and Thermal Expansion Coefficients as an Explanation for Co-Solvent Effect of Penetrants in Multicomponent Polymer Mixtures

“…This hydrogel is inert and therefore suitable for various applications such as diapers, female hygiene products, wound dressings, controlled release drug systems, and solid electrolytes for batteries. [ 6,12,[40][41][42][43] Riberio and Freeman [ 13 ] studied the dilation and sorption processes of carbon dioxide/ethane (CO 2 a concentration range of CO 2 in the gas phase from 10 to 70 mol%. In another study, Claudio and Riberio [ 6,12 ] estimated the PMV of CO 2 and C 2 H 6 in the XLPEO at different temperatures using the binary dilation-sorption data of CO 2 /XLPEO and ethane/XLPEO systems.…”

“…[ 6,12,[40][41][42][43] Riberio and Freeman [ 13 ] studied the dilation and sorption processes of carbon dioxide/ethane (CO 2 a concentration range of CO 2 in the gas phase from 10 to 70 mol%. In another study, Claudio and Riberio [ 6,12 ] estimated the PMV of CO 2 and C 2 H 6 in the XLPEO at different temperatures using the binary dilation-sorption data of CO 2 /XLPEO and ethane/XLPEO systems. The ternary CO 2 (1)/ C 2 H 6 (2)/XLPEO(3) dilation data of Riberio and Freeman [ 13 ] at two different temperatures (i.e., 25 and 35 °C) were used to validate the proposed methodology for the calculation of the PMVs of penetrating molecules in multicomponent systems.…”

“…Similarly, the α value for XLPEO was estimated to be 5.5 × 10 −4 per °C which is in very good agreement with the value of (6.11 ± 0.043) ×10 −4 per °C reported by Claudio and Riberio. [ 6 ] Based on the regression of PMV data of each gas presented in Figure 8 , Equations (12) and ( 13) can be employed to describe the dependence of average PMV of CO 2 and C 2 H 6 on the gas phase composition in XLPEO in the temperature range of 25 to 35 °C, respectively. …”

“…[ 1,[3][4][5][6][7][8][9][10][11][12][13] The PMVs of various gases (or penetrants) in binary gas(1)/polymer(2) mixtures have been estimated for different polymers using experimental dilation, sorption or densimetry data, and hyper-parallel tempering osmotic ensemble techniques. [ 1,2,[4][5][6][7][10][11][12][13][14][15][16] Ternary mixtures (i.e., gas(1)/gas(2)/polymer (3)) represent a simple case of realistic multicomponent systems and, despite of the fact that multicomponent gases/polymer mixtures are very common in polymerization reactors and in the downstream processing units, only few studies have been conducted to estimate or analyze the PMV of the individual species present in such systems. For example, the only known work related to the PMVs of two simultaneously sorbing gases in a single polymer phase was done by Freeman and co-workers, [ 17 ] in which the authors experimentally measured the solubility of pure methane (CH 4 ), pure n-butane (n-C 4 H 10 ), and their mixtures in poly(dimethylsiloxane) (PDMS) at different temperatures and pressures.…”

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

“…Solubility data for CO 2 and a few other gases at 35 °C are available for some materials,8, 9, 14–16 whereas systematic studies at other temperatures were reported by Lin and Freeman19 and Kelman et al18 However, all these data were obtained without considering the effect of polymer dilation, which can lead to errors in the reported solubility data, since experimental methods for measuring gas solubility in polymers are sensitive to the volume of the polymer sample 20, 21. It was only very recently that both sorption and dilation of two gases (carbon dioxide and ethane) in a XLPEO (prepared from PEGDA) were experimentally measured 22. These data confirmed that to obtain more accurate gas solubility values in XLPEOs by the pressure‐decay method, the changes in the volume of the polymer sample due to gas sorption and thermal expansion should be taken into account.…”