Abstract
The separation of montmorillonite (Mt) clay platelets was achieved and optimized through organic modification using cationic (cetyltrimethylammonium bromide [CTAB]) and non-ionic (Tween80) surfactants. Organomodified Mt (oMt) was characterized via particle size analysis, zeta potential, conductivity measurements, Fourier transform infrared (FT-IR) spectroscopy, and x-ray diffraction (XRD). Particle size analysis revealed synergy interaction between surfactants and clay. In CTAB-modified oMt, zeta potential shifted from negative to positive values, indicating increased surface potential. Conductivity decreased upon reaching critical micelle concentration (CMC) level, suggesting micelle formation. FT-IR confirmed the attachment of surfactant functional groups to Mt, whereas XRD verified clay platelet intercalation in both surfactant-modified organoclays. Optimized organoclays were incorporated into starch-based biomaterials, and overall migration as well as specific migration of aluminum (Al) from the resulting bionanocomposite films were assessed for food packaging in accordance with the European Union (EU) and Turkish regulations. The addition of organoclay in matrix effectively lowered overall migration results below the regulatory limit (10 mg/dm(2)) with hydrophilic and acidic food simulants, meeting strict food safety requirements. In specific migration analysis, it was found that although the incorporation of organoclay into biomaterial led to an increase in aluminum migration with acidic simulant, the results remained below the regulation limit (1 mg/kg); meanwhile, the migration levels with aqueous simulant were below the limit of quantification. Moreover, organoclay incorporation significantly decreased both the water absorption capacity and the water solubility of the resulting nanocomposite films. These findings highlight the potential applicability of the developed bionanocomposites for food packaging applications. Practical Application: The successful expansion of organoclay layers was achieved through the use of different surfactants within layered Mt clay. The use of modified organoclays as nanofillers in starch-based biomaterials and the migration of substances from material into acidic and hydrophilic simulants were significantly reduced, bringing them within regulatory limits, resulting in more hydrophobic and stable food packaging materials. Starch-based nanocomposite biopolymers, showing promising potential as substitutes for petroleum-based polymers in food packaging, can guide the safe future use of food packaging, supporting a more sustainable and eco-friendly industry.