Structure-property modification of microcrystalline cellulose film using agar and propylene glycol alginate

Microcrystalline cellulose gum (MCG) forms edible films with poor physical and barrier properties. This study investigated the effects of incorporated agar and propylene glycol alginate (PGA) on structure and property of MCG films. The addition of agar and PGA modified the microstructure and reduced pinholes contributed to lower water vapor permeability (WVP) and improved tensile property of agar-MCG films. However, PGA-MCG had reduced tensile strength possibly due to incompatibility between polymer networks, however, showed a synergistic light barrier. The increased surface hydrophobicity ( approximate to 30 degrees-75 degrees) correlated well with decreased WVP for agar, PGA, and their composites which diverted from pure MCG films. The MCG reduced the thermal stability of agar; however, the PGA had no effect. Conversely, agar and PGA increased the thermal stability of the MCG component. The infrared spectra revealed insignificant H-bonding and molecular interaction between polymers. Therefore, the results indicated that agar and PGA improved stability, mechanical, and barrier properties of edible MCG films via physical entanglement. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45533.