The effect of the number of layers on oxygen transmission and thermoformability of novel multilayer film/foam materials was investigated. Ethylene-vinyl alcohol copolymer/low-density polyethylene multilayered film/foam composites having 16, 32, and 64 alternating layers were developed using continuous multilayer coextrusion process, and the morphology, density, oxygen transmission, and mechanical properties of the as-extruded film/foams were characterized. Tensile properties of the film/foams at elevated temperatures were used to optimize thermoforming conditions. Uniaxial orientation was discovered as an efficient approach to evaluate the potential for thermoforming. Oxygen transmission showed a strong correlation with the thickness reduction which could be used as an indicator for barrier properties of the packaging materials. Film/foam materials with 32 layers demonstrated optimum performance with low oxygen transmission along with high drawing capability.

Production of biopolymer for packaging applications is still a burgeoning demand with the rising environmental concern about pollution due to nondegradable plastic waste materials. This paper introduces a novel approach, yet a continuous production method, to produce PLA multilayer film/foams structures having 16, 32, and 64 alternating layers which were developed by multilayer coextrusion technique, and the morphology, density, mechanical properties and oxygen transmission of the as-extruded film/foams were characterized. The lightweight multilayered PLA film/foam has a unique solid/