Mechanical and thermal behaviour of flexible food packaging polymeric films materials under high pressure/temperature treatments

摘要

The effect of high-pressure processing on mechanical and thermal properties of four complex packaging materials (polyethylenelethylene vinyl alcohol/ polyethylene: PEIEVOHIPE; metallized polyester/polyethylene: PETmetlPE; polyester/ polyethylene: PETIPE; polypropylene SiOx recovered: PPSiOx) was studied. Pouches of the different materials containing distilled water or olive oil as food simulants, as well as empty ones, were subjected to 400 MPa for 30 min, at temperatures of 20 or 60°C. Delamination and wrinkling were a general consequence of the high-pressure processing of multilayer polymeric systems. However, no significant changes were observed regarding the mechanical properties of PE containing laminates after pressurization. PPSiOx underwent significant modifications as SiOx completely broke down. Neither thermal property was affected by pressure, as it was the processing temperature that induced tempering effects on the crystallization behaviour of polymeric components. Only PE/EVOH/ PE, when in contact with water as a simulant, presented a decrease in the melting point temperature.