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Sorption of ethyl acetate and d-limonene in poly(lactide) polymers



Poly(lactide) (PLA) polymers have garnered increased attention in the last few years as food packaging materials because they are environmentally friendly polymers. As the production of PLA increases and price per pound drops, PLA is becoming a growing alternative as a green food packaging material. In this research, the organic vapor barrier properties of commercially available PLA polymers were studied. Gravimetric sorption tests in PLA films were carried out, and the diffusion (D), solubility (S) and permeability (P) coefficients for ethyl acetate and d-limonene in PLA were determined. For ethyl acetate, values of P = 1.22 × 10−17 kg m m−2 s−1 Pa−1, D = 2.63 × 10−15 m2 s−1, and S = 4.62 × 10−3 kg m−3 Pa−1) at 45 °C and a partial pressure of 12 654 Pa were obtained. For d-limonene, no trace was detected after 21 days of testing at 45 °C and 258 Pa, which indicates a permeability coefficient lower than 9.96 × 10−21 kg m m−2 s−1 Pa−1. Poly(lactide) polymers demonstrated good aroma barrier to ethyl acetate and d-limonene, and will most likely be good aroma barriers. PLA is not likely to promote flavor loss by either permeation or scalping. Copyright © 2005 Society of Chemical Industry