Influence of drawing on gas transport mechanism in LLDPE films

Abstract

Micrographs obtained using scanning electron microscopy reveal that the drawing of co-extruded linear low-density polyethylene (LLDPE) films produces numerous changes in their surface. It is necessary to analyse the effect of these changes on gas transport in LLDPE films in order to test their efficiency in the packaging industry. Permeability of He, O-2, N-2 and CO2 has been measured in a temperature range from 25 to 85 degrees C using the variable-pressure technique with the time-lag method. Results show that the drawing process does not have a significant effect on the gas transport mechanism. The influence of drawing on the permeability of LLDPE films to gases is discussed in the light of previous studies of diffusion and mechanical relaxation in the same material and compared with results obtained in the present work.