# 2006 Washington DC
In the oil and gas industry, polymer materials are used for their excellent barrier properties and their main function is to ensure leakproofness. Moreover, these semicrystalline polymers are exposed to different gases (alone or in a mixture) under extreme conditions of temperature and pressure (up to 130°C and up to 1000 bar). Different phenomena may take place over time : solubilization of the gas molecules within and diffusion through the polymer. This paper presents the ongoing work at IFP on the permeability of polymers in term of experimental equipment dedicated to the study of gas mixtures and data obtained. Permeation measurements were performed at different temperatures on a high density polyethylene with pure or mixed gases (methane, carbon dioxide, hydrogen). Hence, the intrinsic permeability coefficient of each component of a gas mixture was determined along with its temperature dependency in one particular case. The objective of such measurements is to assess the existence of specific interactions between the matrix and one type of diffusing molecules. Keywords : Permeation – methane - hydrogen - gas mixture - polyethylene.