Fundamental study of sorption of pure liquids and liquid mixtures into polymeric membrane

• Fundamental study of sorption in low density polyethylene + liquid.
• Liquid of same molar volume: sorption values decrease with increasing dipole moment.
• LDPE + hexane + aromatic compounds: interaction parameter.
• LDPE + toluene + alcohols: pure toluene exhibits the strongest affinity to LDPE.

A fundamental study of the equilibrium sorption of various liquids (water, linear alcohols, linear alkanes, derivates of cyclohexane, aromates, 1-chlorohexane, chlorocyclohexane, chlorobenzene, benzoyl chloride, and nitrobenzene) into the low density polyethylene (LDPE) membrane at three temperatures (15, 25, and 35 °C) is presented. The measurements were carried out using a gravimetric method. The relationship between the equilibrium sorption and the liquid molar volume, the type of the functional group, the molar mass, interaction parameter, and Hildebrand solubility parameter are thoroughly discussed. Generally, the equilibrium sorption of alcohols and water in hydrophobic LDPE are lower than those of alkanes within the indicated temperature range. However, the sorption of alcohols increases with extension of alkyl chain while in case of alkanes it decreases. Furthermore, cyclohexane, benzene, and hexane exhibited higher sorption than their corresponding chloroderivatives (chlorocyclohexane, chlorobenzene, and chlorohexane). The effective interaction parameters for ternary systems LDPE + hexane + aromatic compounds and LDPE + toluene + linear alcohols were determined. In the first case it increases with increasing number of C-atoms in the side chain of aromatic compound. In the second case the interaction parameters indicate that affinity of pure toluene to LDPE is stronger than that of any toluene–alcohol mixture.

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