Effect of temperature on the solubility of aroma compounds in polyethylene film

The sorption characteristics of ester vapors, such as ethyl acetate and ethyl caproate, in low-density polyethylene (LDPE) film were measured using microgravimetry. The sorption isotherms for ester vapors in LDPE film at different temperatures within the range 20-35 °C did not obey the Flory-Huggins equation over the entire range of ester vapor activity, but could be fitted well using the engaged species induced clustering (ENSIC) model. The ks/kp parameters on the ENSIC model and the apparent ΔHmix obtained using the van't Hoff plot for the solubility coefficient are related to the preferential affinity of the penetrant for the polymer and the elastic factor as an endothermic feature, respectively.