Effect of High Pressure Processing on the Thermal and Mechanical Properties of Polyethylene Films Measured by Dynamical Mechanical and Tensile Analyses

This study investigated the influence of high pressure processing on the thermal and mechanical properties of low-density polyethylene (LDPE) films used for food packaging. This was carried out by monitoring the thermal and mechanical properties of the materials before and after the pressure treatments. Pouches made from the LDPE films were pressured at 200, 400 and 800 MPa for 5 and 10 min at 25 and 75°C. The storage and loss moduli, tensile strength and elongation at break and yield of the film samples were then measured using dynamic mechanical analysis (DMA) and an Instron® Universal Tester (Canton, MA, USA), respectively. The DMA was performed at −130 to 85°C, whereas the tensile and elongation analyses were carried out at room temperature. Results of the DMA experiments showed that the storage modulus increased with increasing pressure intensity. The tensile analysis showed that the tensile strength increased but the elongation decreased with increasing pressure treatment.