Evaluation of gas solubility into cis-polyisoprene by molecular simulations

Free-energy related properties of methane, ethane, propane, and butane diss olved into cis-1,4-polyisoprene were calculated using the thermodynamic int egration (TI) method. Solubility coefficient was larger in the order: butan e>propane>ethane>methane both at 100 degreesC and at 0 degreesC. With the d ecrease in the temperature, the solubility coefficients increased for the f our kinds of gas molecules. These results were in good correspondence with the experimental ones, and the absolute values were also satisfactory. The advantages of the evaluation of the solubility using TI method were discuss ed in light of practical uses.