Flaxseed gum/agar blends and nanocomposites: preparation and physical properties

This work was conducted with the objective of improving the physicochemical properties of flaxseed gum with added agar. Three formulations of flaxseed gum/agar (FG/AG) blends (75/25, 50/50 and 25/75) were studied in the presence of glutaraldehyde as crosslinking agent and a glycerol plasticizing agent. Cellulose nanocrystals (CNCs) were used as reinforcing agents at different levels (2%, 4% and 8% w/w) to prepare nanocomposite films by casting polymeric blends of flax seed and agar with both additives. The interaction with water (vapor permeability and solubility), scanning electron microscopy and tensile tests were performed for films, blends and nanocomposites. The flaxseed gum, agar and additives showed good homogeneity, as demonstrated by scanning electron microscopy. All the formulations presented tenacity increase between 585 and 811%, and lower values of solubility relative to the control film (FGcontrol). The best formulation of nanocomposites was 50/50–4% CNCs, that presented higher modulus of elasticity and increase in tenacity of 130% relative to the 50/50 blend and 1588% relative to the control film. The results showed that AG and CNC can modulate the properties of FG, opening numerous opportunities for investigation. Due to the significant improvement in the mechanical properties, FG/AG blends and nanocomposites have excellent potential in applications as sustainable packaging.