EFFECT OF ANNEALING ON THE PERMEATION CHARACTERISTICS OF GASES OF COEXTRUDED LLDPE FILMS

The temperature dependence of both the permeability and diffusion coef ficients of carbon dioxide, oxygen and nitrogen in annealed LLDPE film s are studied. It is found that the values of the permeability coeffic ient through the annealed membranes are nearly four times larger than those through the non-annealed ones. The fact that annealing slightly diminishes the values of the diffusion coefficient leads to the conclu sion that the rise in permeability detected in the films by effect of annealing should be attributed to an increase in solubility. The perme ability characteristics of the films are interpreted in terms of the f ree volume theory. Copyright (C) 1996, Elsevier Science Ltd.