Nine types of polyethylene films for modified atmosphere packaging (MAP) from three supplierswere evaluated for O{sub}2, CO{sub}2, and H{sub}2O vapor transmission rates (OTR,CO{sub}2TR, WVTR, respectively) at four temperatures (0.0, 5.0, 15.5, and 23.2℃).Experimentally measured and quoted OTR were compared and differences of 16.7 were obtainedfor supplier A, 30.8 for supplier B, and 74.2 for supplier C. Bag-to-bag consistency was best forsupplier A followed by B and then C. Measurements on similar films supplied in a different yearshowed good batch-to-batch uniformity. The average ratio of CO{sub}2TR/OTR decreased from5.93 to 5.26 as temperature increased from 0 to 23.2℃, while the average ratio of H2{sub}Opermeance/0{sub}2 permeance (on molar bases) decreased from 80.7 to 47.0. Arrhenius activationenergies (kcal/mole K) averaged 8.73 for 02, 7.77 for CO{sub}2, and 6.22 for H2{sub}O vapor Anincrease in temperature from 0 to 23.2℃ affected OTR the most (compared to its 0℃ value),followed by a slightly smaller effect on CO{sub}2TR (87 of the effect on OTR), and by aconsiderably smaller effect on H2{sub}O permeance (69 of the effect on OTR).
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