Thermodynamic study of water sorption and water barrier properties of nanocomposite films based on brea gum

• Published in: Applied clay science Vol. 108; pp. 144 - 148
• Main Authors: Slavutsky, Aníbal M., Bertuzzi, María A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2015
• Subjects: BG/Mt film; Permeability; Sorption isotherms; Thermodynamic parameters; Thermodynamic parameters; Permeability; BG/Mt film; Sorption isotherms
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2015.02.011

Water transport in edible films based on hydrophilic polymers is a complex phenomenon due to the strong interactions of sorbed water molecules with the polymeric structure. The effect of montmorillonite (Mt) nanoparticle incorporation into brea gum (BG) based films was studied through thermodynamic and phenomenological analyses. Moisture adsorption isotherms at three different temperatures of BG based films and BG/Mt nanocomposite films were obtained. Thermodynamic parameters showed an exothermic process that results less favourable when Mt is incorporated into the BG matrix, reducing the water uptake. Entropy change and net isosteric heat of adsorption showed a peak at monolayer water content, which is greater in composite films, indicating a more stable and ordered structure when Mt was added. Gibb's energy was indicative of process spontaneity and of the lower affinity to water composite films. Water vapour permeability depends on the tortuosity of the pathway formed by Mt nanoparticles and solubility of water molecules into the BG film matrix. Mt incorporation reduces the hydrophilic character of BG based films and thus their water vapour permeability.
•Composite films based on brea gum and Mt nanoparticles were characterized.•Thermodynamic analysis of water sorption process of film matrix was performed.•The effect of driving force on water permeation process was studied.•Mt addition improves barrier properties and water resistance of brea gum films.