Abstract: The influence of temperature, relative humidity, and film thickness on the permeability of PET packaging films was investigated. Based on the gas molecular osmotic reaction kinetics, empirical equations for permeating rates of water vapor, O2, and CO2 were formulated through regression analysis method. With the increasing of ambient temperature, the permeating rate of H2O, O2, and CO2 through PET film and PET/Al film increased. The logarithm of permeating rate of H2O,, and CO2 was linearly related to the reciprocal temperature. In the 12 ?m-thick PET film, the permeating rate of water vapor was independent, in the 20 ?m-thick PET film and 18 ?m-thick PET/Al film, that was weakly dependent of humidity. PET film had prominent perm-selectivity for O2 and CO2, with the permeating rate of CO2 being twice that of O2. The permeating rates of O2 and CO2 in PET/Al film were comparable, both lower than those in PET film.

Key words: packaging, water vapor permeability, gas permeability, polyethylene terephthalate, film