TY - JOUR
T1 - Gas and vapor solubility in cross-linked polyethylene glycol diacrylate
AU - Lin, Haiqing
AU - Freeman, Benny D.
PY - 2005/10/4
Y1 - 2005/10/4
N2 - Polymers containing poly(ethylene glycol) (PEG) have been investigated for CO 2 removal from mixtures with light gases such as CH 4, N 2, and H 2 because of the good affinity of PEG for CO 2. In this study, the solubilities of CO 2 and several hydrocarbons (CH 4, C 2H 4, C 2H 6, C 3H 6, and C 3H 8) were determined as a function of gas fugacity (i.e., pressure) at temperatures ranging from - 20°C to 35°C in cross-linked amorphous poly(ethylene glycol) diacrylate (XLPEGDA), which was prepared by UV photopolymerization of poly(ethylene glycol) diacrylate and contains about 82 wt % PEG. Sorption isotherms were described using the Flory-Huggins model. Unlike Sorption in nonpolar rubbery polymers, solubility of gases such as CO 2 and olefins in polar XLPEGDA do not vary systematically based on parameters used conventionally to characterize gas condensability such as critical temperature (T c) or (T c/T) 2, so a new model is proposed to correlate the data. CO 2 exhibits the lowest Flory - Huggins interaction parameter (i.e., χ) values among all of the penetrants considered, indicating favorable interactions with XLPEGDA. Although gas solubility at a given pressure generally increases as temperature decreases, χ values increase with decreasing temperature for all penetrants except CO 2. These results reflect the interplay between increases in penetrant condensability as temperature decreases, which tend to increase solubility, and increases in the unfavorable interactions between the gas and polymer segments (reflected in the increased χ values) as temperature decreases, which tend to reduce solubility. χ values for CO 2 in XLPEGDA decrease with decreasing temperature, which is another indication of the affinity between CO 2 and XLPEGDA. The following example illustrates the effect of temperature on intermolecular interactions: CO 2/C 2H 6 solubility selectivity at infinite dilution increases from 2.7 to 6.6 as temperature decreases from 35°C to - 20°C, even though these two penetrants have almost the same condensability as characterized by T c. Furthermore, gas solubility values in XLPEGDA are very similar to those in amorphous PEG at infinite dilution and 35°C, suggesting that the PEG linkages in XLPEGDA dominate its sorption properties.
AB - Polymers containing poly(ethylene glycol) (PEG) have been investigated for CO 2 removal from mixtures with light gases such as CH 4, N 2, and H 2 because of the good affinity of PEG for CO 2. In this study, the solubilities of CO 2 and several hydrocarbons (CH 4, C 2H 4, C 2H 6, C 3H 6, and C 3H 8) were determined as a function of gas fugacity (i.e., pressure) at temperatures ranging from - 20°C to 35°C in cross-linked amorphous poly(ethylene glycol) diacrylate (XLPEGDA), which was prepared by UV photopolymerization of poly(ethylene glycol) diacrylate and contains about 82 wt % PEG. Sorption isotherms were described using the Flory-Huggins model. Unlike Sorption in nonpolar rubbery polymers, solubility of gases such as CO 2 and olefins in polar XLPEGDA do not vary systematically based on parameters used conventionally to characterize gas condensability such as critical temperature (T c) or (T c/T) 2, so a new model is proposed to correlate the data. CO 2 exhibits the lowest Flory - Huggins interaction parameter (i.e., χ) values among all of the penetrants considered, indicating favorable interactions with XLPEGDA. Although gas solubility at a given pressure generally increases as temperature decreases, χ values increase with decreasing temperature for all penetrants except CO 2. These results reflect the interplay between increases in penetrant condensability as temperature decreases, which tend to increase solubility, and increases in the unfavorable interactions between the gas and polymer segments (reflected in the increased χ values) as temperature decreases, which tend to reduce solubility. χ values for CO 2 in XLPEGDA decrease with decreasing temperature, which is another indication of the affinity between CO 2 and XLPEGDA. The following example illustrates the effect of temperature on intermolecular interactions: CO 2/C 2H 6 solubility selectivity at infinite dilution increases from 2.7 to 6.6 as temperature decreases from 35°C to - 20°C, even though these two penetrants have almost the same condensability as characterized by T c. Furthermore, gas solubility values in XLPEGDA are very similar to those in amorphous PEG at infinite dilution and 35°C, suggesting that the PEG linkages in XLPEGDA dominate its sorption properties.
UR - http://www.scopus.com/inward/record.url?scp=26944438685&partnerID=8YFLogxK
U2 - 10.1021/ma051218e
DO - 10.1021/ma051218e
M3 - Article
AN - SCOPUS:26944438685
SN - 0024-9297
VL - 38
SP - 8394
EP - 8407
JO - Macromolecules
JF - Macromolecules
IS - 20
ER -