Rheological, morphological, mechanical, and water-barrier properties of agar/gellan gum/montmorillonite clay composite films

Abstract

Agar (A), gellan gum (G) and montmorillonite (M) based ternary nanocomposite films were prepared via the solution-casting method for food packaging applications. The prepared nanocomposites were investigated for the effect of MMT clay on the structure–property relationships by studying the microstructural, rheological, mechanical, thermal, ultraviolet, and water-barrier properties of AG hydrogel composites. The results indicated that the thermal stability (T5%: 119.4–174.7) and tensile strength (29.9–44 MPa) were significantly enhanced in the reinforced MMT nanoclay. The water barrier (1.9–1.7) and contact angle (56.8°–49.4°) were reduced by the incorporation of MMT clay whereas the rheological properties improved. The AGM composite solution exhibited shear thinning behavior and viscosity reduction at a high rate. Additionally, the composites exhibited significantly higher storage and loss modulus at high frequencies. The complex viscosity differed from the shear viscosity and remained higher than the shear viscosity. The nanocomposite structure, molecular interaction, and interaction in the multicomponent were investigated by FT-IR, XRD and SEM analysis. The AG and AGM nanocomposites exhibited a synergistic reinforcement effect. The results of this study might introduce a new route for enhancing the nanocomposites for sustainable materials.