Thermoplastic starch and poly(vinyl alcohol) blends centered barrier film for food packaging applications

This study explores the potential use of a Thermoplastic Starch (TPS)/Polyvinyl Alcohol (PVOH) blend as an alternative center-layer material to ethylene vinyl alcohol (EVOH) in food packaging films. Multi-layer films consisting of a TPS/PVOH blend center-layer sandwiched between low-density polyethylene (LDPE) outer layers were prepared in a co-extruded blown film line. Middle-layer blend concentration of TPS was varied from 0 to 100 wt% and the barrier and mechanical properties were characterized. Films with center layer blends containing 25 and 75 wt% TPS exhibited similar oxygen barrier properties to neat EVOH. Moreover, multi-layer films containing 25 wt% TPS center-layers showed the highest tensile strength and dart impact value among all blends and this was attributed to an enhanced interaction between blend constituents. The study suggests that the blends containing either 25 or 75 wt% TPS could serve as alternative barrier layers due to their relatively low material cost, good oxygen barrier performance and adequate material properties.