engleski

Polyethylene/polycaprolactone nanocomposite films for food packaging modified with magnetite and casein: oxygen barrier, mechanical and thermal properties

Low density polyethylene (PE-LD), as traditional food packaging material, is modified in order to improve its barrier, mechanical and thermal properties since they are crucial for the application. For that purpose double layer polyethylene/polycaprolactone (PE/PCL) films were prepared with the addition of magnetite and casein. Active components were added to the PCL coating film to improve barrier properties and prevent destruction of basic structure of the primary polyethylene film. Low interactions between matrix-filler usually result in aggregation of active component when biopolymers are used as carriers. By preparing bionanocomposite homogenous dispersion of magnetite and enhancement of its efficiency has been provided. The casein is suitable carrier of magnetite nanoparticles because of its porous structure. The role of magnetite (Fe3O4) was to slow down the oxygen permeability as its act as oxygen scavenger. Significant improvements were observed with regards to mechanical (tensile strength, elongation at break) and thermal properties, while barrier (O2 permeability) properties were slightly improved. Overall migration values into acetic acid, for all studied materials, were lower (from 1 to 4.6 mg/dm2) than the upper limit set by the legislation. Specific migration of iron in PE/PCL-Fe samples is also below (µg/L) SML value set by the legislation (mg/kg).

casein ; low density polyethylene (PE-LD) ; magnetite ; overall migration ; oxygen permeability ; polycaprolactone (PCL) ; polymer nanocomposite ; thermal stability

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