This work reports the permeation of argon through membranes prepared from poly(pentaerythritoltribenzoate acrylate) (PPTBA) (IUPAC name poly[1-(3-benzoyloxy-2,2-dibenzoyloxymethylpropyloxy)-2-propen-1-one]). The permeation measurements were performed in the vicinity of the glass transition temperature of the membranes (48 °C). The permeation coefficient only shows a slight dependence on temperature in the glassy state, but it undergoes a sharp increase with temperature in the rubbery state. The results for the diffusion coefficient do not show a definite temperature dependence in the glass−rubber transition. As expected, the solubility of the gas in the membrane is higher in the rubbery state than in the glassy state. The diffusion coefficient was calculated theoretically by using the Transition-State Approach which assumes that the diffusant path is independent of the structural relaxations in the polymer matrix. Reasonably good agreement between the simulated and the experimental values of the diffusion coefficient was obtained in the range of temperatures from 40 to 60 °C in which the measurements were performed.

The permeation of argon gas through membranes of poly(cis/trans 2-phenyl-5-ethyl-5acryloxymethyl-1,3-dioxacyclohexane) (PAEDP) has been measured in the vicinity of the glass transition temperature of this polymer (∼Tg≈50 °C). Both the permeation and the diffusion coefficients show only a slight dependence on temperature while the membrane remains in glassy state, but exhibit a sharp increase with temperature in the rubbery state. Theoretical calculations of the diffusion coefficient were performed according to the transition-state approach, i.e., assuming that the diffusant path is independent of the structural relaxation in the polymeric matrix, as a function of the smearing factor Δ and temperature. Reasonably good agreement among theoretical and experimental values of the diffusion coefficient was obtained. Theoretical calculations were also performed for poly(cis/trans 2-phenyl-5-ethyl-5-methacryloxymethyl-1,3-dioxacyclohexane) (PMAEDP), the methacrylate analog of PAEDP, which indicate that the diffusion coefficient of glassy PMAEDP is lower than that of glassy PAEDP when the same temperature is taken as the basis of comparison, due to the higher values of Tg in methacrylate than in acrylate polymers which, in turn is a consequence of the rigidity conferred to the polymeric chain by the methyl group.

The permeation behavior of different ethylene‐1‐hexene, ethylene‐1‐octene, and ethylene‐1‐dodecene copolymers synthesized with metallocene catalysts has been analyzed. These copolymers cover a wide range of comonomer contents, so their crystallinities display rather considerable variations. The results for the permeability to oxygen of the different ethylene copolymers show that the main factor influencing the permeability is the noncrystalline fraction, although some influence of the kind of comonomer may also be present, which may be explained by the fact that when the alkyl branch of the α‐olefin is longer, there is an increase in the free volume in the amorphous and interfacial regions, causing slightly higher values of the permeability coefficient. From the results with different gases, it follows that, in general, an increase in the size of the penetrant (as expressed by its kinetic diameter or critical molar volume) leads to an increase in the solubility and a decrease in the diffusion coefficient. A wide range of permeability values is covered by these ethylene copolymers, depending basically on the crystallinity of the sample, but the permselectivity of CO2 with respect to oxygen (and probably between other pairs of gases) does not differ very much among the different copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2174–2184, 2003

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A series of methacrylic copolymers was prepared by radical polymerization of the monomers 2-ethoxyethyl methacrylate and 2-hydroxyethyl methacrylamide and a small quantity of a cross-linking agent ethylene glycol dimethacrylate. Water swelling of the membranes, mechanodynamical analysis, density measurements, and ATR-FTIR studies were performed on the copolymers. High vacuum pressure techniques were used to evaluate the flow of He, O2, N2, CO2, CH4, CH3CH3, and CH2CH2 through these membranes, and solubility, diffusivity, and permeability coefficients were determined. The effect of the increase of the amount of methacrylamide in the copolymer on transport properties, glass transition, fractional free volume, cohesive energy density, and specific interactions has been studied and is reported in this work.

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This work describes the preparation, characterization, and evaluation of the oxygen permeability of blends based on a polyolefin synthesized with a metallocene catalyst (ethylene/1‐octene copolymer) and a vinyl alcohol/ethylene copolymer in an attempt to establish the corresponding relationships between the composition, morphology, and transport properties to design materials with optimized and enhanced agricultural and food packaging performances. Moreover, microhardness measurements have been used to analyze the mechanical response of these blends and to obtain information about the dispersion of the two immiscible components within the blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3766–3774, 2004