Determination of Hansen Solubility Parameters by means of gas-solid inverse gas chromatography

Abstract

The determination of Hansen Solubility Parameters (HSP) from inverse gas chromatographic (IGC) data for a group of nano-materials and modified nano-materials is presented and discussed. The solubility parameter concept is applied in many industries to explain the different properties of the various components in a formulation. Knowledge of the solubility parameter data for different components is important for predicting the magnitude of the interaction between the formulation components and the future stability of the product. Solubility parameter data are also useful in the description and interpretation of different phenomena occurring between materials such as their miscibility, compatibility or adsorption. The inverse gas chromatography method is widely used for the characterization of polymers and polymer blends, surfactants, biopolymers, solid food and petroleum pitches. The method involves placing the investigated material (stationary phase) in a column and then characterizing it using volatile probes with known properties (test solutes) which are carried by a mobile phase. The solubility parameter called the Hildebrand solubility parameter or the Hildebrand parameter is only applied for regular solutions. The so-called Hansen solubility parameter (HSP) is an extension of the Hildebrand solubility parameter to polar and hydrogen-bonding systems. Hansen assumed that the cohesive energy can be considered as the sum of the contributions from dispersive (Ed), polar (Ep) and hydrogen-bonding (Eh) interactions: -Ecoh = -Ed - Ep - Eh; and that the total solubility parameter (δT) may be expressed as δ T2 = δd2 +δp2 + δh2, where δp, δp and δh denote the dispersive, polar and hydrogen-bonding contribution, respectively. The estimation of HSP from IGC data for a group of nano-materials and modified nano-materials is presented and discussed here.