Equilibrium and transient sorption of vapours and gases in the polymer of intrinsic microporosity PIM-1

Determination of multi-component gas and water equilibrium and non-equilibrium sorption isotherms in carbonaceous solids from early-time measurements

A detailed investigation has been carried out of the pre-polymerisation modification of the polymer of intrinsic microporosity PIM-1 by the addition of two methyl (Me) groups to its spirobisindane unit to create a new chemically modified PIM-1 analogue, termed MePIM. Our work explores the effects of this modification on the porosity of PIM-1 and hence on its gas sorption properties. MePIM was successfully synthesised using either low (338 K) or high (423 K) temperature syntheses. It was observed that introduction of methyl groups to the spirobisindane part of PIM-1 generates additional microporous spaces, which significantly increases both surface area and hydrogen storage capacity. The BET surface area (N2 at 77 K) was increased by ~ 12.5%, resulting in a ~ 25% increase of hydrogen adsorption after modification. MePIM also maintains the advantages of good processability and thermal stability. This work provides new insights on a facile polymer modification that enables enhanced gas sorption properties.

Gas sorption in polymers of intrinsic microporosity: The difference between solubility coefficients determined via time-lag and direct sorption experiments

Sensitivity of the parameters of the dual-mode sorption (DMS) model on the pressure range, in which sorption of gases in polymers have been studied, was analyzed. Different “gas-polymer” systems were considered but the most detailed analysis was performed for sorption of argon and nitrogen in poly[5,5-difluoro-6,6-bis(trifluoromethyl)] norbornene and polysulfone. It was shown that the model parameters depend upon the range of gas pressure studied. Expanding of the pressure range (0-pi) results in an increase in the Langmuir adsorption capacity C′H and in reduction of Henry's law solubility coefficient kD and Langmuir affinity parameter b. These behaviors does not depend on a choice of an experimental apparatus or software and procedure of nonlinear least squares treatment of the data. As statistical analysis indicated, a systematic error of the measurement cannot call forth the observed dependencies of the model parameters. Different physical reasons of these behaviors were considered, among them: the pressure dependence of the affinity parameter, and the dilation of a polymer. The results obtained showed that although the DMS model, as a rule, gives an excellent fit of the experimental curves, and, hence, can be used as a form of compact storage of information on gas sorption in polymers, one should be careful in using it outside the pressure range in which its parameters have been determined. © 1996 John Wiley & Sons, Inc.

Sensitivity of the parameters of the dual-mode sorption (DMS) model on the pressure range, in which sorption of gases in polymers have been studied, was analyzed. Different “gas-polymer” systems were considered but the most detailed analysis was performed for sorption of argon and nitrogen in poly[5,5-difluoro-6,6-bis(trifluoromethyl)] norbornene and polysulfone. It was shown that the model parameters depend upon the range of gas pressure studied. Expanding of the pressure range (0-pi) results in an increase in the Langmuir adsorption capacity C′H and in reduction of Henry's law solubility coefficient kD and Langmuir affinity parameter b. These behaviors does not depend on a choice of an experimental apparatus or software and procedure of nonlinear least squares treatment of the data. As statistical analysis indicated, a systematic error of the measurement cannot call forth the observed dependencies of the model parameters. Different physical reasons of these behaviors were considered, among them: the pressure dependence of the affinity parameter, and the dilation of a polymer. The results obtained showed that although the DMS model, as a rule, gives an excellent fit of the experimental curves, and, hence, can be used as a form of compact storage of information on gas sorption in polymers, one should be careful in using it outside the pressure range in which its parameters have been determined. © 1996 John Wiley & Sons, Inc.

Gas sorption and transport of ozone-treated polysulfone

Gas sorption isotherms in swelling glassy polymers—Detailed atomistic simulations

Modeling of vapor sorption in glassy polymers using a new dual mode sorption model based on multilayer sorption theory

The suitability of the Guggenheim–Anderson–De Boer (GAB) model for the parameterization of gas sorption isotherms and their dependences on temperature is explored. The GAB model implies that molecules adsorb on inner surfaces of the polymer in multilayers, which contrasts with the assumptions of the classical Dual Mode Sorption (DMS) model which implies the simultaneous occurrence of Henry-like dissolution and Langmuir's case I adsorption. The GAB model shows similar efficacy of the parameterization of the gas sorption isotherms in polymers as the DMS model. The isosteric heat of adsorption shows clear dependence on relative surface coverage for carbon dioxide sorption in cellulose acetate, polyethylene terephthalate, and the first polymer of intrinsic microporosity (PIM-1), thus allowing for the occurrence of adsorption multilayers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1490–1495

Enhanced gas separation performance of PIM-1 blend membranes incorporating ionic liquid (3-(trimethoxysilyl) propan-1-aminium acetate ([APTMS][Ac])) as filler: Investigation of morphology, compatibility and transport properties

Impeded physical aging in PIM-1 membranes containing graphene-like fillers

Polymers of intrinsic microporosity (PIMs) havereceived considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades, owing to their highly permeable porous structures. However, challenges regarding its relatively low selectivity, physical aging, and plasticisation impede relevant industrial adoptions for gas separation. To address these issues, several strategies including chain modification, post-modification, blending with other polymers, and the addition of fillers, have been developed and explored. PIM-1 is the most investigated PIMs, and hence here we review the state-of-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementionedchallenges via meta-analysis. Additionally, the development of PIM-1-based thin film composite membranes is commented as well, shedding light on their potential in industrial gas separation. We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.

This study presents the fabrication of a new mixed matrix membrane using two microporous polymers: a polymer of intrinsic microporosity PIM-1 and a benzimidazole linked polymer, BILP-101, and their CO2 separation properties from post-combustion flue gas. 17, 30 and 40 wt% loadings of BILP-101 into PIM-1 were tested, resulting in mechanically stable films showing very good interfacial interaction due to the inherent H-bonding capability of the constituent materials. Gas transport studies showed that BILP-101/PIM-1 membranes exhibit high CO2 permeability (7200 Barrer) and selectivity over N2 (15). The selected hybrid membrane was further tested for CO2 separation using actual flue gas from a coal-fired power plant.

Pure and mixed gas sorption of carbon dioxide and ethylene in poly(methyl methacrylate)

Barrier polymers are used for many packaging and protective applications. As barriers they separate a system, such as an article of food or an electronic component, from an environment. Barrier polymers limit movement of substances, called permeants. The movement can be through the polymer or, in some cases, merely into the polymer. After crossing the barrier polymer, the permeant moves to the polymer surface, desorbs, and moves away. Permeant movement is a physical process that has both a thermodynamic and a kinetic component. For polymers without special surface treatments, the thermodynamic contribution is in the solution step. The permeant partitions between the environment and the polymer according to thermodynamic rules of solution. The kinetic contribution is in the diffusion. The net rate of movement is dependent on the speed of permeant movement and the availability of new vacancies in the polymer. The traditional definition of a barrier polymer required an oxygen permeability less than \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${2{\hskip0.167em}{\hskip0.167em}{\rm{nmol}}/{(}{\rm{m}} {\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em} {\rm{s}}{\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em} {\hskip-0.167em}{\rm{GPa}}{)}}$\end{document} (originally, less than \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${{(}1{\hskip0.167em}{\hskip0.167em}{\rm{cc}}{\hskip-0.167em} {\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em}{\rm{mil}}{)}/{(}100{\hskip0.167em}{\hskip0.167em}{\rm{in}} ^{2}{\hskip-0.167em} {\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em}{\rm{d}} {\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em} {\rm{atm}}{)}}$\end{document} ) at room temperature. Poly(ethylene terephthalate) (PET), with an oxygen permeability of \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${8{\hskip0.167em}{\hskip0.167em}{\rm{nmol}}/{(}{\rm{m}} {\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em} {\rm{s}}{\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em} {\hskip-0.167em}{\rm{GPa}}{)}}$\end{document} , is not considered a barrier polymer by the old definition; however, it is an adequate barrier polymer for holding carbon dioxide in a 2‐L bottle for carbonated soft drinks. Many months are required to lose enough carbon dioxide (15% of initial) to be objectionable. The polymers that are good barriers to permanent gases, especially oxygen, have important commercial significance. Vinylidene chloride copolymers are available as resins for extrusion, latices for coating, and resins for solvent coating. Vinylidene chloride copolymers are marketed under a variety of trade names. Saran is a trademark of The Dow Chemical Company for vinylidene chloride copolymers. Other trade names include Daran (W.R. Grace), Amsco Res (Union Oil), and Serfene (Morton Chemical) in the United States; and Haloflex (Imperial Chemical Industries, Ltd.), Diofan (BASF), Ixan (Solvay and Cie SA), and Polyidene (Scott‐Bader) in Europe. Hydrolyzed ethylene–vinyl acetate copolymers, commonly known as ethylene–vinyl alcohol (EVOH) copolymers, are usually used as extrusion resins, although some may be used in solvent‐coating applications. Copolymers of acrylonitrile are used in extrusion and molding applications. Commercially important comonomers for barrier applications include styrene and methyl acrylate. Polyamide polymers can provide a good‐to‐moderate barrier to permeation by permanent gases. Two often‐used polymers have adequate properties for some applications. Poly(ethylene terephthalate) (PET) is used to make films and bottles. Poly(vinyl chloride) (PVC) is a moderate barrier to permanent gases. Plasticized poly(vinyl chloride) is used as a household wrapping film. In regard to water vapor transmission (WVTR) values, those polymers that are good oxygen barriers are often poor water‐vapor barriers and vice versa. Polymer molecules without dipole–dipole interactions, such as polyolefins, dissolve very little water and have low WVTR and permeability values. The permeation of flavor, aroma, and solvent molecules in polymers follows the same physics as the permeation of small molecules, but with two significant differences. For these larger molecules, the diffusion coefficients are much lower and the solubility coefficients are much higher. Furthermore, the large solubility coefficient can lead to enough sorption of the large molecule that plasticization occurs in the polymer, which can increase the diffusion coefficient. Generally, vinylidene chloride copolymers and glassy polymers such as polyamides and EVOH are good barriers to flavor and aroma permeation, whereas the polyolefins are poor barriers. Several physical factors can affect the barrier properties of a polymer. These include temperature, humidity, orientation, and cross‐linking. Typically, the permeability increases 5 to 10% for every increase of 1°C. When a polymer equilibrates with a humid environment, it absorbs water. This can plasticize the polymer and increase the permeability. The effect of orientation on the permeability of polymers is difficult to assess; diffusion in some polymers is unaffected by orientation; in others, increases or decreases are observed. Cross‐linking has been shown in a few cases to decrease the diffusion coefficient. Reasonable prediction can be made of the permeabilities of low molecular weight gases such as oxygen, nitrogen, and carbon dioxide in many polymers. The diffusion coefficients are not complicated by the shape of the permeant, and the solubility coefficients of each of these molecules do not vary much from polymer to polymer. Reasonable predictions of the permeabilities of larger molecules such as flavors, aromas, and solvents are not easily made. The diffusion coefficients are complicated by the shape of the permeant, and the solubility coefficients for a specific permeant can vary widely from polymer to polymer. The permachor method is an empirical method for predicting the permeabilities of oxygen, nitrogen, and carbon dioxide in polymers. In this method a numerical value is assigned to each constituent part of the polymer. An average number is derived for the polymer, and a simple equation converts the value into a permeability. The model has been modified to liquid permeation with some success. For larger molecules, independent predictions of the diffusion coefficients and the solubility coefficients are required. Predicting the diffusion coefficient for a permeant in a polymer requires knowing one other diffusion coefficient in the polymer. The solubility coefficients are more difficult to predict. Although advances are being made, the best method is probably to use a few known solubility coefficients in the polymer to predict others. Measuring the barrier properties of polymers is important for several reasons. The effects of formulation or process changes need to be known, new polymers need to be evaluated, data are needed for a new application before a large investment has been made, and fabricated products need to have performance verified. Two methods of measuring water‐vapor transmission rates (WVTR) are commonly used. The newer method uses a Permatran‐W (Modern Controls, Inc.). The other method is the ASTM cup method. Measuring the permeation of carbon dioxide occurs far less often than measuring the permeation of oxygen or water. The simplest method uses the Permatran‐C instrument (Modern Controls, Inc.). Many methods are used to characterize the transport of flavor, aroma, and solvent molecules in polymers. Each has some value, and no one method is suitable for all situations. Any experiment should obtain the permeability, the diffusion coefficient, and the solubility coefficient. The primary application for barrier polymers is food and beverage packaging. Barrier polymers are also used for packaging medical products, agricultural products, cosmetics, and electronic components and in moldings, pipe, and tubing. The use of safe materials is vital for barrier applications, particularly for food, medical, and cosmetics packaging. Suppliers of specific barrier polymers can provide the necessary details to ensure safe processing and use of barrier polymers.