Biodegradable starch/PVOH/laponite RD-based bionanocomposite films coated with graphene oxide: Preparation and performance characterization for food packaging applications

Starch and poly (vinyl alcohol) (PVOH)-based packaging is of great importance and has additional benefits over petroleum-based packaging due to abundant availability, biodegradability and compatibility. The aim of this research is to propose advances for the preparation of bionanocomposites prepared by the combination of intercalation from solution and melt-mix methods. The effect of the laponite RD content on the mechanical and barrier properties of starch/PVOH-based films was evaluated. Starch and PVOH (1:1 to 4:1) were blended with laponite RD (LRD) (0–20% polymer basis) to form bionanocomposite films of thickness ranging between 200 and 400 μm. Presence of laponite RD improved the mechanical barrier properties of starch/PVOH matrix up to 10% level of laponite RD because of better surface interface interaction between polymer matrix and layers of laponite RD. Water absorption studies showed higher water absorption and % solubility for solution mix compared to melt-mix method. Furthermore, the graphene oxide coating was used to improve the water barrier property of starch/PVOH/laponite RD-based bionanocomposites. Laponite levels and graphene oxide have significant effects on barrier properties of bionanocomposites film at P < 0.01 and P < 0.05, respectively. Water absorption was found minimum with a coat having 10% laponite RD and 25:75 graphene:lipid proportion. Thus, these results indicate that the exfoliated starch/PVOH/LRD nanocomposites have great potential for industrial applications and more specifically in the packaging field.