Production of nanocomposite films based on low density polyethylene/surface activated nanoperlite for modified atmosphere packaging applications

The modified atmosphere packaging films based on polyethylene nanocomposites reinforced with perlite nanoparticles were prepared using a blow molding machine. The perlite particles were first reduced to nano dimensions using an abrasive mill, then the porosity of nanoperlite was increased to improve their efficiency in absorbing ethylene gas. For this purpose, 6 normal sodium hydroxide solution at 50°C temperature was used. Finally, perlite nanoparticles were modified by polymethyl hydrogen siloxane silane compound. In each of the stages of grinding and modifying the perlite surface, the necessary tests including dynamic light diffraction test, nitrogen absorption test and ethylene gas absorption test were performed using gas chromatography method. The results showed that the size of perlite particles was reduced to 500 nm by using an abrasive mill, and the surface modification process increased the specific surface area of perlite by 10 times. Based on this, the amount of ethylene gas absorption in perlite nanoparticles with modified surface increased up to 3 times compared to normal perlite. The results of the gas chromatography test showed that the nanocomposite film based on polyethylene reinforced with 6% by weight of modified perlite nanoparticles has several times the efficiency in absorbing ethylene gas compared to the potassium permanganate sachets The results of the mechanical properties tests of nanocomposite film in comparison with pure polyethylene film showed that nanocomposite film has higher properties than pure polyethylene. The results of shelf-life tests of green tomatoes packed in nanocomposite film based on polyethylene reinforced with modified nanoperlite showed that green tomatoes can be stored for two months using the prepared modified atmosphere packaging.