The sorption behavior of CO2 gas in photocrosslinked poly(vinyl cinnamate)
film was examined under atmospheric pressure. The sorption isotherm was wel
l described by the Langmuir equation, suggesting that sorption of CO2 is ma
inly governed by adsorption in the microvoids. The amount of sorbed CO2 was
significantly affected by the degree of crosslinking. The CO2 sorption was
enhanced at a lower degree of crosslinking but was decreased at a higher d
egree of crosslinking. The unexpected increase in the amount of adsorbed CO
2 correlated with the increase in the number of microvoids that occurred as
a result of the crosslinking reaction. However, further crosslinking led t
o a decrease in the mean size of the microvoids. The smaller microvoids, in
comparison to CO2 molecules, did not act as adsorption sites, so that the
amount of sorbed CO2 decreased. (C) 2000 John Wiley & Sons, Inc.