The effect of pressure on the permeation of gases and vapors through polyethylene. Usefulness of the corresponding states principle

Abstract

The permeation of carbon dioxide through polyethylene membranes has been studied at pressures up to 54.4 atm. and a t temperatures above and below the critical temperature of the gas (31.0"C.l. The permeability coefficient is independent of pressure a t the highest experimental temperature (61 .O"C.), but becomes increasingly pressure-dependent as the temperature is lowered. The principle of corresponding states can be used to correlate the solubility of both gases and vapors in polyethylene over a wide range of temperatures. This principle can also be invoked to obtain an upper limit for the penetrant pressure above which the permeability coefficient becomes pressure-dependent. The effect of pressure on the permeability, solubility, and diffusivity of gases and vapors in polyethylene is discussed in some detail.Although the mechanism of gas permeation through plastic membranes has been studied by many investigators, surprisingly little information is available on the effect of gas pressure on the rate of permeation. In general, the literature suggests that the permeation of gases with low critical temperatures, such as helium, hydrogen, oxygen, and nitrogen, can be described under steady state conditions by a simple form of Fick's law, and that the permeability coefficients for these gases are independent of pressure (1 ) . Carbon dioxide and hydrogen sulfide have been reported to exhibit a similar behavior (1 to 3 ) .On the other hand, the permeability coefficients for many organic vapors, which are characterized by high critical temperatures, were found to be strongly pressure dependent (1, 4, 5).

Gas and Vapor Sorption, Permeation, and Diffusion in Glassy Amorphous Teflon AF1600

“…A similar result has been obtained for AF2400 and for semicrystalline polyethylene. 30 A least-squares treatment of the data for the hydrocarbon penetrants in Figure 3 yields the following result: Solubility coefficients measured at different temperatures obey the following correlation with reduced critical temperature squared as suggested by Stern et al 30 In Table 4, parameters for eq 12 are presented for several polymers. It is worthwhile to note that independent of the chemical nature and physical state of polymers (amorphous glassy or rubbery, semicrystalline) similar slopes are observed.…”

Solubilities of ethylene and other organic solutes in liquid, low‐density polyethylene in the region 124° to 300°C

“…The correlation of Stern et al (1969), although presented in a form applicable for all temperatures and solute critical temperatures, is mainly based on solubility data for semicrystalline polyethylene near 25°C. The only data for liquid polyethylene are the five light-gas data of Durrill and Griskey ( 1966).…”

Transport Properdines of Gases in Polymers: Bibliographic Review

“…A certain number of relations were proposed to describe the evolution of the logarithm of S with various parameters such as the critical gas temperature (Van Amerongen, 1950;Suwandi and Stern, 1973;Stern et al, 1969), the boiling temperature or the Lennard-Jones parameters (Gee, 1947;Michaels and Bixler, 1961a;Van Krevelen, 1990;Flaconnèche et al, 2001). All these parameters, except in the presence of specific polymer-gas interactions, will raise with the penetrant size.…”