Synthesis and characterization of κ-carrageenan bio-nanocomposite films reinforced with bentonite nanoclay.

Due to ecological reason, in the last period there is an increased interest for changing the synthetic based materials with biodegradable ones. In this study, we prepared bio-nanocomposite formulations based on κ-Carrageenan (κ) and bentonite nanoclay (BT) with different component concentrations (0% BT, 5% BT, 10% BT and 15% BT respectively) and investigated their structural features, with focus on the interactions, sorption properties, and how the combination between them influences these properties. By infrared spectroscopy was identified that in the blending process hydrogen bonds and/or electrostatic interactions may have occurred between BT and κ. The water uptake and water sorption ability decreased with the increasing of the BT content in the formulations, from about 12% for κ to 9% for κ-BT 85:15% and from about 128% for κ to 121% for κ-BT 85:15%, respectively. Water adsorption can significantly decrease if the reinforcement materials are homogenusly dispersed in the matrix. The increase of the BT content induced also a decrease of the water contact angle at the surface from 76 for κ to 27 for κ-BT 85:15%.