Solubility and diffusivity of cyclohexane in two different polyethylenes



The solubility and diffusivity of cyclohexane in a very low density polyethylene (VLDPE) have been measured over a range of temperatures and concentrations. These data provide an interesting contrast to similar data for high density polyethylene. Above the melt temperatures, the solubilities for both polyethylenes follow the same correlation as a function of the activity. Below the melt temperature, however, a correction is needed to correlate the solubility that accounts for the elasticity effects caused by the polymer chains between the crystals. The capabilities of two models that can predict the solubility and the free-volume model for the correlation of the diffusivity have been analyzed. Unlike in previous studies, the diffusivity in the VLDPE does not appear to be influenced significantly by the presence of crystals. POLYM. ENG. SCI., 55:688–692, 2015. © 2014 Society of Plastics Engineers