Sodium caseinate-starch-modified montmorillonite based biodegradable film: Laboratory food extruder assisted exfoliation and characterization

The present work aims at using a laboratory food extruder for exfoliating starch-montmorillonite (nanoclay) blend and uses the extrudate for blending with sodium caseinate for developing a bionanocomposite film (OP). Exfoliation of nanoclay was confirmed by TEM and XRD pattern. SEM revealed that surface of OP film was rough. Nanoclay addition had significant effect on tensile strength, elongation at break, water sorption and solubility of the film. Glass transition temperature of OP film was 44 °C. Moisture sorption isotherm was found to be of type-II with a typical sigmoid shape. FTIR spectra revealed that formaldehyde and nanoclay caused minor changes and the film was completely biodegradable within 114 h. Overall migration into n-heptane was found to be lowest among all food simulants. It was concluded that laboratory food extruder could be used to achieve exfoliation of nanoclay and develop a bionanocmposite film.