Mechanical and Gas Permeability Properties of Nanocomposite Films Made From Low Density Polyethylene and Carbon Nanotubes

Abstract

It is important to develop new food packaging materials with enhanced properties. In this work, nanocompositewas prepared by melt blending linear low density polyethylene (LLDPE) and multiwalled carbon nanotubes (MWCNT) by using twin-screw extruder, then hot-pressing was applied to produce nanocomposite films. The effect of the addition of three different dimensions of MWCNT on the mechanical and gas permeabilities properties was investigated, along with overall migration. According to the film characterization results by scanning electron microscopy, the dispersion of MWCNT in general was considerably average. The presence of interaction networks between LLDPE–MWCNT was observed, so did the presence of carbon nanotubes agglomerations. Relatively better dispersion was achieved by the nanocomposite films containing 0.25 wt. % MWCNT at any dimension. It was observed that the dispersion of carbon nanotubes corresponded with the improvement in mechanical and gas barrier properties. The consistent improvement was shown in Young‘s modulus with the increment up to 26.9 % as the content of MWCNT increased. Moreover, the addition of MWCNT could enhance the gas barrier properties by lowering the gas permeabilities up to 26.5 % and 32 % for oxygen and carbondioxide, respectively. The results from mechanical properties and gas permeabilities revealed that the content of MWCNT was more crucial to affect the improvement rather that its dimension. In terms of overall migration, the results were found below the limit required by European Union Commission (10 mg/dm2). Considering these outstanding results, the developed material could be applied in food packaging, particularly in active packaging system.