Transport properties of gases through integrally skinned asymmetric composite membranes prepared from date pit powder and polysulfone

Studies were conducted on transport properties and separation performance of date pit/polysulfone composite membranes for CO₂, CH₄, N₂, He, and H₂ gases. Date seeds were obtained and processed into powder. Asymmetric flat sheet membrane was prepared by solvent casting method with 2–10 wt % date pit powder. Membrane characterization was done using high pressure gas permeation, X‐ray diffraction, thermogravimetric, and scanning electron microscope analyses. The separation performance and the plasticization resistance property were evaluated in terms of gas permeability, selectivity, and plasticization pressure, respectively. Time dependent performance properties were evaluated up to a pressure of 40 bar for 75 days. Results obtained showed the highest selectivity values of 1.54 (He/H₂), 3.637 (He/N₂), 2.538 (He/CO₂), 2.779 (He/CH₄), 3.179 (H₂/N₂), 3.907 (H₂/CO₂), 1.519 (CH₄/N₂), 1.650 (CO₂/N₂), and 1.261 (CO₂/CH₄) at 10 bar and 35 °C feed pressure and temperature, respectively. The resulting composite membrane showed about 39.50 and 66.94% increase in the selectivity of He/N₂ and CO₂/CH₄, respectively, as compared to the pure polysulfone membrane. Thus, the membrane composites possess some potentials in membrane gas separation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43606.     

Preparation and Characterization of Polycarbonate-Blend-Raw/Functionalized Multi-Walled Carbon Nano Tubes Mixed Matrix Membrane for CO2 Separation

Membrane composed of PC as base of polymer matrix with different ratio of multiwall carbon nano tubes (MWCNTs) as nanofillers and poly ethylene glycol (PEG) as second polymer was prepared by solution casting method. Both raw-MWCNTs (R-MWCNTs) and functionalized carboxyle-MWCNTs (C-MWCNTs) were used in membrane preparation. The MWCNTs loading ratio and pressure effects on the gas transport properties of membranes were examined in relation to pure He, N₂, CH₄, and CO₂ gases. Results showed that the use of C-MWCNT instead of R-MWCNTs in mixed matrix membranes (MMMs) fabrication with base of PC provides better performance and also it increases (CO₂/CH₄) and (CO₂/N₂) selectivities to 27.38 and 25.42 from 25.45 and 19.24, respectively (at 5 wt% of MWCNTs). PEG as the second rubbery polymer was utilized to improve the separation performance and mechanical properties. In blend MMMs, highest (CO₂/CH₄) selectivity at 2 bar pressure increased to 35.64 for PC/PEG/C-MWCNT blend MMMs which was 27.28 for PC/MWCNTs MMMs at 10 wt%. Increase of feed pressure led to gas permeability and gas pair selectivity improvement in approximately all of membranes. Analysis of mechanical properties showed improvement in tensile modules with the increase of MWCNTs loading ratio and use of PEG in prepared MMMs.     

Effect of coating method on gas separation by PDMS/PES membrane

In this study, polydimethylsiloxane (PDMS)‐coated polyethersulfone (PES) composite membrane was prepared for gas separation. “Film casting” and “dip‐coating” techniques were used for producing selective PDMS layer on the surface of the PES support. The effects of coating technique and conditions including coating solution concentration and curing temperature on permselectivity of CO₂, CH₄, and N₂ were investigated. The prepared PES support did not provide any selectivity to the gases. When the concentration of PDMS coating solution was increased, initially permeability of CO₂ was rapidly dropped and then gradually reached to an almost constant value. The optimum concentration of coating solution was 5 wt%. Curing temperature showed no pronounced effect on the CO₂ permeability and selectivity. In “film casting” method, double coating showed superior permeability and selectivity. However, triple “dip‐coating” was promising. The selectivity of composite membrane prepared by “dip‐coating” was higher than “film casting” method. CO₂/N₂ and CO₂/CH₄ selectivity of five sequential dip‐coated composite membranes was 45.5 and 9.3, respectively. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

Sorption studies of CO<Subscript>2</Subscript>, CH<Subscript>4</Subscript>, N<Subscript>2</Subscript>, CO,O<Subscript>2</Subscript> and Ar on nanoporous aluminum terephthalate [MIL-53(Al)]

Aluminum terephthalate, MIL-53(Al), metal–organic framework synthesized hydrothermally and purified by solvent extraction method was used as an adsorbent for gas adsorption studies. The synthesized MIL-53(Al) was characterized by powder X-Ray diffraction analysis, surface area measurement using N₂ adsorption–desorption at 77 K, FTIR spectroscopy and thermo gravimetric analysis. Adsorption isotherms of CO₂, CH₄, CO, N₂, O₂ and Ar were measured at 288 and 303 K. The absolute adsorption capacity was found in the order CO₂>CH₄>CO>N₂>Ar>O₂. Henry’s constants, heat of adsorption in the low pressure region and adsorption selectivities for the adsorbate gases were calculated from their adsorption isotherms. The high selectivity and low heat of adsorption for CO₂ suggests that MIL-53(Al) is a potential adsorbent material for the separation of CO₂ from gas mixtures. The high selectivity for CH₄ over O₂ and its low heat of adsorption suggests that MIL-53(Al) could also be a compatible adsorbent for the separation of methane from methane–oxygen gas mixtures.     

Sorption and transport of gases in miscible poly(methyl acrylate)/poly(epichlorohydrin) blends

The sorption and the transport of He, Ar, N₂, CH₄, and CO₂ in miscible poly(methyl acrylate)(PMA)/poly(epichlorohydrin)(PECH) blends from 1 to 20 atm at 35°C are reported. For He, Ar, N₂, and CH₄, the permeabilities and the diffusion time lags are independent of the upstream pressure, if the compaction effect resulting from compression of the polymer membrane onto the supporting medium is eliminated. The permeability of CO₂ increases with upstream pressure but solubility follows a simple Henry's law behavior. For all five gases, the dependence of solubility, diffusion coefficient, and permeability on blend composition are compared with theoretical mixing rules with the conclusion that both the interaction energy density and the excess activation energy for gas diffusion in the blends are near zero. The fact that the specific volumes of the blends exactly follow linear additivity also confirms that only very weak interactions exist between PMA and PECH.     

Asymmetric polysulfone gas separation membranes treated by low pressure DC glow discharge plasmas

Asymmetric polysulfone (PSF) gas separation membranes were prepared at different conditions such as non‐solvent concentration, evaporation time (ET) and coagulation bath temperature (CBT). In addition, effects of low‐pressure DC glow discharge plasma on the characteristics of PSF membranes were investigated. PSF membranes both before and after plasma treatment were characterized by several techniques, including contact angle measurement, scanning electron microscope (SEM), dynamic mechanical thermal analysis (DMTA), and atomic force microscopy (AFM). Furthermore, the performance of membranes was evaluated in terms of permeability of CO₂, CH₄, O_2, and N₂ gases. The ideal selectivity of CO₂/CH₄ and O₂/N₂ and surface free energy was calculated. Results showed that the EtOH concentration, ET and CBT affect the morphology of PSF membranes. For membranes prepared from a casting solution consisting of PSF 26.0, NMP 28.0, THF 28.0, and EtOH 18.0 wt % and ET for 3 min, the maximum selectivity of untreated membrane is about 69.76 and 12.59 for CO₂/CH₄ and O₂/N₂, respectively. After plasma treatment, the ideal selectivity is receded; however, the CO₂/CH₄ is still higher than 40.41 at pressure of 5 bars. Finally, preparation conditions and DC glow discharge plasmas have significant effects on the characteristics of the PSF membranes and result in an increase of the gas permeation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42116.     

Fabrication and modification of cellulose acetate based mixed matrix membrane: Gas separation and physical properties

[Cellulose acetate (CA)-blend-multi walled carbon nano tubes (MWCNTs)] mixed matrix membranes (MMMs), [CA/polyethylene glycol (PEG)/MWCNTs] and [CA/styrene butadiene rubber (SBR)/MWCNTs] blend MMMs were prepared by solution casting method for gas separation applications using Tetrahydrofuran (THF) as solvent. Both raw-MWCNTs (R-MWCNTs) and functionalized carboxylic-MWCNTs (C-MWCNTs) were used in membrane preparation. The MWCNTs loading ratio and pressure effects on the gas separation performance of prepared membranes were investigated for pure He, N₂, CH₄ and CO₂ gases. Results indicated that utilizing C-MWCNT instead of R-MWCNTs in membrane fabrication has better performance and (CO₂/CH₄) and (CO₂/N₂) selectivity reached to 21.81 and 13.74 from 13.41 and 9.33 at 0.65 wt% of MWCNTs loading respectively. The effects of PEG and SBR on the gas transport performance and mechanical properties were also investigated. The highest CO₂/CH₄ selectivity at 2 bar pressure was reached to 53.98 for [CA/PEG/C-MWCNT] and 43.91 for [CA/SBR/C-MWCNT] blend MMMs at 0.5 wt% and 2 wt% MWCNTs loading ratio respectively. Moreover, increase of feed pressure led to membrane gas permeability and gas pair selectivity improvement for almost all prepared membranes. The mechanical properties analysis exhibited tensile modules improvement with increasing MWCNTs loading ratio and utilizing polymer blending.     

Adsorption and separation of CH4/CO2/N2/H2/CO mixtures in hexagonally ordered carbon nanopipes CMK-5

Adsorption and separation of N₂, CH₄, CO₂, H₂ and CO mixtures in CMK-5 material at room temperature have been extensively investigated by a hybrid method of grand canonical Monte Carlo (GCMC) simulation and adsorption theory. The GCMC simulations show that the excess uptakes of pure CH₄ and CO₂ at 6.0 MPa and 298 K can reach 13.18 and 37.56 mmol/g, respectively. The dual-site Langmuir–Freundlich (DSLF) model was also utilized to fit the absolute adsorption isotherms of pure gases from molecular simulations. By using the fitted DSLF model parameters and ideal adsorption solution theory (IAST), we further predicted the adsorption separation of N₂–CH₄, CH₄–CO₂, N₂–CO₂, H₂–CO, H₂–CH₄ and H₂–CO₂ binary mixtures. The effect of the bulk gas composition on the selectivity of these gases is also studied. To improve the storage and separation performance, we finally tailor the structural parameters of CMK-5 material by using the hybrid method. It is found that the uptakes of pure gases, especially for CO_2, can be enhanced with the increase of pore diameter D_i, while the separation efficiency is apparently favored in the CMK-5 material with a smaller D_i. The selectivity at D_i=3.0 nm and 6.0 MPa gives the greatest value of 8.91, 7.28 and 27.52 for S_CO2/N2, S_CH4/H2 and S_CO2/H2, respectively. Our study shows that CMK-5 material is not only a promising candidate for gas storage, but also suitable for gas separation.     

Effect of air gap on gas permeance/selectivity performance of BTDA‐TDI/MDI copolyimide hollow fiber membranes

Fabrication, morphology evaluation , and permeance/selectivity properties of three asymmetric BTDA‐TDI/MDI copolyimide hollow fiber membranes (HFM s ) are reported. The asymmetric HFM s were spun using the dry/wet phase inversion process. The effect of one of the major spinning parameters, the air gap, on the permeance/selectivity properties of the produced HFM was investigated. Scanning e lectron m icroscopy was used to evaluate the morphological characteristics and the macroscopic structure of the developed HFM. The permeance values of He, H₂, CH₄, CO₂, O₂, and N₂ gases were measured by the variable pressure method at different feed pressures and temperatures and the permselectivity coefficients were calculated. The higher selectivity values were evaluated for the Μ1 membrane and were found to be 49.33, 2.99, 5.13, 5.57 , and 9.61 for H₂/CH₄, O₂/N₂, CO₂/CH₄, CO₂/N₂ , and H₂/CO₂ gas mixtures , respectively. The selectivity experiments of H₂/CH₄, CO₂/CH₄ , and O₂/N₂ mixtures were performed at 25 ° C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4490–4499, 2013     

Gas transport properties of polyaniline membranes

The transport properties of He, H₂, CO₂, O₂, N₂, and CH₄ gases in solvent cast, HCl doped, and undoped polyaniline (PANi) membranes were determined. Measurements were carried out at 40 psi pressure from 19°C to 60°C. An excellent correlation was found between the diffusion coefficients and the molecular diameters of gases. The solubility coefficients of gases were found to correlate with their boiling points or critical temperatures. The sepa-ration factors for CO₂/N₂ and CO₂/CH₄ are dominated by the high solubility of CO₂. These correlations enable us to predict the permeability, diffusion, and solubility coefficients of other gases. After the doping-undoping process, the fluxes of gases with kinetic diameters smaller than 3.5 Å increased but those of larger gases decreased. This results in a higher separation factor for a gas pair involving a small gas molecule and a larger one. © 1996 John Wiley & Sons, Inc.     

Gas Separation Properties of Phosphazene Polymer Membranes

Abstract

In this paper the gas separation properties of poly[bis(phenoxy)phosphazene] are reported. Transport behavior was determined by time-lag techniques and correlated with membrane microstructural studies. Test gases were run as pure or single-species gases, which included atmospheric gases, hydrocarbons, sulfur dioxide, and hydrogen sulfide. Transport of atmospheric and hydrocarbon gases was found to be a diffusion controlled processr; i.e., correlated with molecular size. Transport of CO₂, H₂S, and SO₂ was found to be a sorption controlled process since high solubilities were measured and transport deviated from the diffusion controlled permeability-size correlation. Membranes were prepared using spin and knife casting techniques. Solvent evaporation rate during the casting process was used to provide different membrane microstructures. Rapid evaporation by spin casting resulted in dense homogeneous films, with permeabilities ranging from 2–6 barrers for the slowest (Ar) to fastest gases (He). Slow evaporation by knife casting (minutes-hours) resulted in a more open polymer structure. Two enhancement effects were observed in the transport behavior of the knife-cast membrane: 1) an overall increase in permeability for all gases depicting the more open membrane structure (ranged from 4–76 barrers for all gases) and 2) an enhancement of the selectivity of gases which exhibited strong solubility effects. Sulfur dioxide and hydrogen sulfide exhibited the greatest selectivity enhancements. The pure gas solubility selectivities for S0₂ and H₂S with respect to the atmospheric and hydrocarbon gases were found to be approximately 1000 and 200 respectively.     

Structural and transport properties of polydimethylsiloxane based polyurethane/silica particles mixed matrix membranes for gas separation

Mixed matrix membranes of synthesized polyurethane (PU) based on toluene diisocyanate (TDI), polydimethylsiloxane (PDMS) and polytetramethylene glycol (PTMG) with polyvinyl alcohol based polar silica particles were prepared by solution casting technique. The homogeneity and thermal properties of the prepared PDMS-PU/silica membranes were characterized using scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The SEM micrographs confirmed the distribution of silica particles in the polymer matrix without agglomerations. Gas permeation properties of membranes with different silica contents were studied for pure CO₂, CH₄, O₂, He and N₂ gases. The obtained results indicated the permeability of the condensable and polar CO₂ gas was enhanced whereas permeability of other gases decreased upon increasing the silica content of the mixed matrix membranes. The permeability of CO₂ and its selectivity over N₂ was increased from 68.4 Barrer and 22 in pure PDMS-PU to 96.7 Barrer and 64.4 in the mixed matrix membranes containing 10 wt% of the silica particles.     

Effect of doping treatment on gas transport properties and on separation factors of polyaniline memebranes

Gas permeation experiments of H₂, O₂, CO₂, N₂, and CH₂ were carried out with freestanding films of the conjugated polymer polyaniline (PANi). At first annealed to remove residual solvent, PANi membranes were doped (i.e., protonated) in a strongly acidic medium (HCl 4M), undoped in a basic medium (NH₄OH 1M), and redoped in a slightly acidic medium (HCl 10^?2M). Protonation and deprotonation kinetics were studied by elementary analysis Gas permeation experiments were performed with the annealed, doped, undoped, and redoped PANi films. The gas transport mechanism was clearly influenced by the diffusivity factor and it obeyed a Fickian diffusion model. From the variations in permeability coefficients with the doping treatment, gases could be divided in two subgroups comprising H₂, O₂, and CO₂ on one hand and N₂ and CH₄ on the other. After the doping–undoping–redoping process, gas fluxes were increased by 15% for the smaller gases and were decreased by 45% for the larger gases. As a consequence gas separation factors were approximately doubled for a gas pair involving the two subgroups and these were unchanged for a gas pair involving only one subgroup. The highest O₂/N₂ and CO₂/CH₄ selectivity coefficients were, respectively, equal to 14 and 78. © 1995 John Wiley & Sons, Inc.     

CO2/CH4/N2在沸石13X-APG上的吸附平衡

采用磁悬浮热天平测量了CO₂、CH₄与N₂在沸石13X-APG上的吸附等温线,温度为293、303、333和363 K,压力为0～500 kPa。对吸附平衡实验数据采用multi-site Langmuir模型和Sips模型进行拟合,均得到良好的拟合效果,非线性回归得到吸附热等模型参数,可为变压吸附工艺过程的开发提供基础热力学数据。将沸石13X-APG吸附分离性能与文献中报道的吸附材料(如沸石分子筛、活性炭、金属有机骨架材料和介孔硅分子筛)性能相比较。通过比较CO₂、CH₄与N₂吸附容量以及相对分离系数,探讨CO₂/CH₄(垃圾填埋气或者CO₂强化煤层甲烷回收气)体系、CO₂/N₂(燃煤电厂、水泥厂以及焦炭厂烟道气)体系以及CH₄/N₂(煤层气)体系吸附分离的高效材料,为未来二氧化碳吸附捕集和甲烷吸附回收提供基础数据。     

Mixed-Gas Separation Properties of Phosphazene Polymer Membranes

Abstract

In this paper the mixed-gas separation properties of poly[bis(phenoxy)phosphazene] based polymers are reported. Transport behavior was determined using the variable volume technique. Test gases were run as mixed-gas pairs including SO₂/N₂, H₂S/CH₄, and CO₂/CH₄. Transport of these gases was found to be a sorption controlled process since these gases significantly deviated from the diffusion controlled permeability-size correlation. Membranes were prepared using solution casting techniques. Solvent evaporation rate during the casting and subsequent curing processes was controlled to provide a consistent membrane microstructure. We have observed that polyphosphazene membranes can effectively be used to separate acid gases from various waste streams in harsh, chemically aggressive environments.     

Effect of Feed Composition on the Gas Separation Performance of Binary and Ternary Mixed Matrix Membranes

Binary and ternary component mixed matrix membranes comprised of zeolite 4A and p-nitroaniline (pNA) in the polycarbonate (PC) matrix were prepared and appraised in gas separation. For comparison, homogenous membranes of PC and PC/pNA membranes were also investigated. The membranes were utilized to separate binary mixtures of CO₂/CH₄, H₂/CH₄, and CO₂/N₂. The effect of feed composition on the separation performance of membranes was investigated. Separation factors and ideal selectivities were similar for the PC membrane. A similar trend was also observed with the PC/pNA membrane. The separation factors of the PC/pNA membrane for CO₂/CH₄ were almost twice as high as those of the PC membrane regardless of the feed composition. The ideal selectivities were, however, higher than separation factors for PC/zeolite 4A and PC/pNA/zeolite 4A membranes. The PC/ pNA/zeolite 4A membrane has separation factors of 18 for 77% CO₂/ 23% CH₄ mixture, and 40 for 20% CO₂/ 80% CH₄ mixture, respectively. The separation factors of the mixed matrix membranes depended on the feed composition strongly. The PC/ pNA/zeolite 4A membrane had higher separation factors and lower permeabilities than the PC/zeolite 4A membrane. pNA assisted to eradicate partly the detrimental effects of interfacial voids and improved the molecular sieving effect of zeolite 4A dispersed in the PC.     

Separation of binary mixtures of carbon dioxide and methane through sulfonated polycarbonate membranes

Polycarbonate (PC) was sulfonated to varying degrees using acetyl sulfate. FTIR and NMR experiments were carried out to confirm sulfonation. The membranes were characterized by DSC and TGA to assess thermal stability. Ion exchange capacity (IEC) and degree of sulfonation (DS) were determined and their effect on permeation of CO₂ and CH₄ gases was investigated. Free volume fractions (FVF) of the membranes were found to decrease from 0.31 to 0.19 as the DS increased from 0 to 39.4%. Single gas permeation studies revealed that sulfonated PC exhibited higher selectivities than unmodified PC at reduced permeability. For a DS of 14.4%, sulfonated PC exhibited a selectivity of 36.1, which was 1.7 times that of unmodified PC, whereas the permeability dropped from 8.4 to 4.7 Barrers. In case of binary CO₂/CH₄ mixture permeation through PC membrane of the same DS, an increase in CO₂ feed concentration from 5 to 40 mol % produced an increase in permeability from 0.24 to 2.0 Barrers and a rise in selectivity from 11.7 to 27.2 at constant feed pressure (20 bar) and temperature (30°C). A rise in the feed pressure from 5 to 30 bar at a constant feed composition of 5% CO₂ resulted in a reduction in permeability from 0.38 to 0.2 Barrers and selectivity from 15.6 to 10.2. Sulfonated PC was found to be a promising candidate for separation of CO₂ from CH₄. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Gas permeation properties of poly(2,5‐benzimidazole) derivative membranes

In this article, three novel polymers based on poly(2,5‐benzimidazole) (ABPBI) were synthesized by introducing propyl, isobutyl or n‐butyl groups to its side chain through an alkyl substitution reaction. FTIR and ¹³C NMR were applied to confirm the formation of corresponding chemical groups. Their physical properties including crystallinity, thermal stability, mechanical strength, and micro‐morphology were also characterized. Their solubility in common solvents were also tested to see if the modification will bring any improvement. Gas permeation properties of three derivative membranes prepared by a casting and solvent‐evaporation method were tested with pure gases including H₂, N₂, O_2, CH₄, and CO₂. It has been revealed that gas with a smaller molecular size owned a larger permeability. This means gas permeation in all prepared membranes should be diffusivity selective. Among all three modified ABPBI membranes, isobutyl substitution modified ABPBI (IBABPBI) showed the best selectivity of H₂ over other gases such as N₂ (～185) and CO₂ (～6.3) with a comparable permeability (～9.33 barrer) when tested at 35°C and 3.0 atm. Testing temperature increase facilitated gas permeation for all three membranes obviously; while in term of gas selectivity temperature increase showed diverse alteration because it brought variable impact on gas solubility of different gases. Even so, IBABPBI membrane still owned acceptable selectivity of H₂ over N₂ (～118) and CO₂ (～6.3) with an almost doubled permeability (～17.5 barrer) when tested at 75°C and 3.0 atm. Additional tests showed that running at high pressure did not bring any obvious deterioration to gas separation performance of IBABPBI membrane. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40440.     

Incorporation of carbon nanofibers into a Matrimid polymer matrix: Effects on the gas permeability and selectivity properties

Composite membranes containing carbon nanofibers (CNFs) and Matrimid were prepared by a solution‐casting method. Prepared Matrimid–CNF composite membranes were characterized with X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and mechanical testing techniques. The mechanical properties of the composite membranes increased over that of the pristine polymeric membranes. To develop a broad fundamental understanding of the connection between the composite architecture and gas‐transport properties, both the gas‐permeability and gas‐separation characteristics were evaluated. The gas‐transport properties of the Matrimid–CNF composite membrane was measured with a single gas‐permeation setup (He, H₂, N₂, CH₄ and CO₂) at ambient temperature with the variable‐volume method. The incorporation of CNFs (0.5–10 wt %) into the Matrimid matrix resulted in approximately a 22% reduction in the gas permeation of various gases, (H₂, He, CO₂, N₂, and CH₄). Moreover, an improvement of 1.5 times in the gas selectivity was observed for CO₂/CH₄, H₂/CH₄, He/CH₄, and H₂/N₂ compared to pristine polymeric membrane. Hence, such polymer–CNF composite membranes could be suitable for gas‐separation applications with high purity requirements. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46019.     

Sorption and transport of inert gases in PVF2/PMMA blends

Sorption and transport of several inert gases (He, Ar, N₂, and CH₄) in miscible blends of PMMA and PVF₂ are reported as a function of pressure at 35°C. For each gas, the permeabilities are independent of pressure for all blend compositions. Sorption isotherms are linear for rubbery compositions (PVF₂-rich) and nonlinear for glassy compositions (PMMA-rich) as expected. In contrast to CO₂, these gases do not plasticize any of these materials. The data are analyzed using appropriate models for sorption and transport, and the parameters are correlated in terms of blend composition and molecular characteristics of the gases. Effects of crystallinity are discussed. Sorption behavior is compared with poly(methyl acrylate) and poly(vinyl acetate).