Application of the group contribution approach to Nafion swelling

Abstract

The anisotropic swelling of Nafion 112 membrane in pure organic liquids was monitored by an optical method. The findings were used as a basis for application of the group contribution method to the relative expansion in equilibrium. From a total of 38 organic liquids under study, 26 were selected as an evaluational set from which the group and structural group contributions were assigned. The remaining 12 compounds were used as the testing set.Value of AE1.5% in relative expansions was determined to be the experimental error. Maximum differences between the experimental and calculated relative expansions in both sets did not exceed the value of AE3%.

Group Contribution Methods for Estimation of Selected Physico-Chemical Properties of Organic Compounds

“…The models for estimation of several physical or physico-chemical properties of pure organic compounds, such as enthalpy of vaporization, entropy of vaporization (Kolská et al, 2005), liquid heat capacity (Kolská et al, 2008) and a Nafion swelling (Randová et al, 2009) is presented below. Most of them are developed to estimate property at constant temperature 298.15 K and at normal boiling temperature (Kolská et al, 2005;Kolská et al, 2008;Randová et al, 2009), liquid heat capacity as a temperature dependent (Kolská et al, 2008).…”

“…Most of them are developed to estimate property at constant temperature 298.15 K and at normal boiling temperature (Kolská et al, 2005;Kolská et al, 2008;Randová et al, 2009), liquid heat capacity as a temperature dependent (Kolská et al, 2008). Hitherto unpublished results for estimation of a flash temperature or organic compounds and for determination of reactivation abbility of reactivators of acetylcholinesterase inhibited by inhibitor are presented in this chapter.…”

“…(Randová et al, 2009). In many applications Nafion is immersed in liquid, which significantly affects the membrane properties, namely swelling and transport properties of permeates (Randová et al, 2009). The change in the size of the membrane sample is taken as a measure of swelling.…”

“…The change in the size of the membrane sample is taken as a measure of swelling. All experimental data were presented (Randová et al, 2009) and these results were used as a basis for application of the group contribution method to the relative expansion in equilibrium. From a total of 38 organic liquids under study, 26 were selected as an evaluational set from which the group and structural group contributions were assigned.…”

“…Authors have to develop new group structural fragments. The proposed method utilizes the four kinds of the structural units: constants, C-backbone, functional groups, and molecular geometry (Randová et al, 2009). Constants were presented as alcohols, ketones, ethers, esters, carboxylic acids.…”