Gas mixture solubilities in polyethylene below its melting temperature: Experimental and molecular simulation studies

• Published in: Journal of membrane science Vol. 390; pp. 194 - 200
• Main Authors: Memari, Peyman, Lachet, Véronique, Klopffer, Marie-Hélène, Flaconnèche, Bruno, Rousseau, Bernard
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2012; Elsevier
• Subjects: artificial membranes; Carbon dioxide; Chemistry; Colloidal state and disperse state; Exact sciences and technology; Gas mixture solubility; gases; General and physical chemistry; Hydrogen; melting point; Membranes; Methane; Monte Carlo method; polyethylene; Semicrystalline polyethylene; solubility; temperature; Methane; Hydrogen; Semicrystalline polyethylene; Carbon dioxide; Gas mixture solubility; Validation; Monte Carlo method; Polyethylene; Experimental data; Melting; Gas mixture; Constraint; Solubility; Polymer; Density; Gases; Simulation; Membrane
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2011.11.035

► We have computed and measured gas solubilities in polyethylene. ► Computations use Monte Carlo simulations in the osmotic ensemble. ► Crystalline morphology is accounted for using a uniform external stress. ► Gas solubilities for methane–carbon dioxide and methane–hydrogen have been obtained. ► Simulations are in good agreement with experimental values which validates our methodology. We present solubility values of gas mixtures (CH 4 + CO 2 and CH 4 + H 2) in polyethylene below its melting temperature. The objective of such studies is to assess the existence of specific interactions between the matrix and one type of penetrant molecule. Data were acquired using both experiments and molecular simulations. Experiments were performed on a medium density polyethylene with pure and mixed gases for temperatures in the range 308–313 K. Hence, the solubility coefficient of each component of a gas mixture was determined. Monte Carlo simulations in the osmotic ensemble were also used to predict gas concentrations in the polymer phase. A good agreement with experimental data is observed. This is a significant validation of the use of an ad hoc constraint in the osmotic ensemble simulations to mimic the overall effect of the crystalline regions and to predict quantitatively solubility data in this semicrystalline system.