engleski

Barrier properties of a new generation of packaging materials

In this paper a commercially available triplex foil with SiOx deposit (poly (ethylene - terephthalate / poly (ethylene - terephthalate + SiOx / polyethylene) was analysed for its gas permeance characteristics before and after different treatments. For this purpose permeance of triplex foil to oxygen, nitrogen and carbon dioxide was analysed under following conditions: a) temperature range from 20 o to 60 oC; b) flexural endurance from 30 to 150 stress cycles, at 20 oC. Generally, the used triplex foil retained initial barrier properties up to the temperature of 60 oC, showing an inflection point at 40 oC. A linear approximation, of permeability coefficient in close temperature range, showed good agreement with the Arrhenius equation with high coefficient of determination obtained (R2 > 89 %). The activation energy for permeation is between 6.3 J mol-1 and 11.5 J mol-1 for oxygen and carbon dioxide, respectively. Nitrogen permeance of triplex foil is almoust unaffected after being submitted to 150 full flex cycles. In case of oxygen and carbon dioxide a significant decrease in permeance is obtained at 70 and 100 cycles applied (from initially 200 to 20 cm3 m-2 d-1 bar-1).

barrier properties; flexural endurance; temperature; triplex foil

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