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Capturing CO 2 from flue gas of coal-burned power plants has been considered to be a promising technology to mitigate the environmental problems caused by rising level of CO 2 at the atmosphere. Amine-functionalized adsorbents, showing impressive CO 2 adsorption capability and selectivity even at low CO 2 partial pressure, face the challenge of permanent structural changes and performance deterioration due to the irreversibly bonding of SO 2 , a common impurity of flue gas, particularly under humid condition. Besides, the reported amine-functionalized adsorbents are usually nano-sized powders, impractical for industrial applications. Therefore, the development of efficient, stable, and structured CO 2 adsorbents is still an urgent need. Herein, we develop a novel structured mixed-matrix adsorbent (PIM-PP-DETA), using a diethylenediamine-appended porous organic copolymer (PP-DETA, prepared by a copolymerization reaction of dichloro- p -xylene and 4,4′-bis(chloromethyl)biphenyl and a one-step amine grafting process) as main adsorbent and PIM-1 as polymer matrix through a phase inversion process. The as-developed PIM-PP-DETA not only exhibits high CO 2 adsorption capacity and outstanding CO 2 selectivity over N 2 , but also shows fast adsorption kinetics and high stability under repeated adsorption-desorption cycling under dynamic flow conditions. Furthermore, PIM-PP-DETA possesses high tolerance towards acidic and moist environments, with CO 2 adsorption capacity remained at a relatively high level after SO 2 and humid exposure, suggesting its potential usage to post-combustion CO 2 capture. [Display omitted] • PP-DETA was prepared from a porous organic copolymer by an amine grafting process. • PIM-PP-DETA was fabricated via a phase conversion process with PIM-1 as the matrix. • PIM-PP-DETA appeared as robust spherical beads with hierarchical porosity. • It showed outstanding CO 2 /N 2 separation performance and fast adsorption kinetics. • It possessed good cycling performance and high tolerance towards SO 2 and moist. [ABSTRACT FROM AUTHOR]

Gas separation properties are reported for self-standing polymer of intrinsic microporosity (PIM) films after addition of palladium (II) acetate or iron (II) acetate by solid state or liquid state mixing. Membranes, with thicknesses in the range 35–55 μm, were prepared from three high molar mass PIMs, two different branched versions of the much-reported PIM-1 (PIM-1a and PIM-1b) and of PIM-Py. Addition of either Fe(OAc) 2 or Pd(OAc) 2 to all three PIMs led to a reduction in permeability and increase in selectivity, but the permeability reduction was much greater for Pd(OAc) 2 , which is able to interact with branch points in the PIM and crosslink the polymer. CO 2 /CH 4 selectivity of membranes containing Pd(OAc) 2 was poor upon aging, especially after solid state addition to the PIM-1 polymers, for which CO 2 permeabilities dropped to below 200 Barrer after 85 days. Hydrogen permeability and H 2 /N 2 selectivity of membranes containing Pd(OAc) 2 did more closely follow conventional permeability/selectivity trade off upon aging. This illustrates the profound differences that can arise in gas permeation properties and aging behaviour from variations in chemical structure and macromolecular characteristics, and from the addition of metal acetates that interact with the polymer in different ways. [Display omitted] • Branched PIM-1 crosslinked with Pd(OAc) 2 produced membranes with reduced permeability. • Loss in CO 2 permeability on aging not matched with increase in CO 2 /CH 4 selectivity. • Loss in H 2 permeability on aging matched with increase in H 2 /N 2 selectivity. • Crosslinks block smaller free volume elements that dominate CO 2 /CH 4 selectivity. • Fe(OAc) 2 mixed PIM-1 membranes maintain permeability/selectivity balance. [ABSTRACT FROM AUTHOR]

The synthesis of three novel aromatic polyimides (PIs) containing spiro units is described. These PIs are soluble at room temperature in most common organic solvents, facilitating their processability. Additionally, they are highly thermally stable, with thermal decomposition temperatures (T d10% ) over 500 °C, and had moderately high T g values between 230 and 265 °C. Robust self-standing thin films were prepared from these polyimides, via the solution casting method, which were suitable for gas transport measurements. The relatively low permeability and selectivity of these PIs, as compared to Polymers of Intrinsic Microporosity (PIMs) that also contain spirocyclic structures, demonstrate the importance of restricting rotation within the polymer chain, which is a key structural feature of the PIMs. [ABSTRACT FROM AUTHOR]

High-molecular-weight (number average molecular weight M n = 11–81 kDa) polymers with intrinsic microporosity (PIM) were prepared by the solution polycondensation of 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1′-spirobisindane, decafluorobiphenyl, and bisphenols in an aprotic polar solvent at an initial monomer concentration of 0.1 mol/L at 100°C-140 °C for 10–144 h. Transparent (minimum cutoff wavelength of 310 nm), highly thermostable (glass transition temperature of 161°C-376 °C by dynamic mechanical analysis, and 5% weight loss temperature in N 2 of 410°C-514 °C) polymer films were fabricated using a solvent-cast method. The copolymer films showed good mechanical properties (tensile strengths of 45–67 MPa, breaking elongation of 2.2%–23.1%, and tensile elastic moduli of 1.5–3.3 GPa) and insulating properties (relative permittivity of 2.27–2.59, and dissipation factor of 0.00191–0.00466 at 20 GHz frequency). The prepared new PIM copolymers are candidates for next-generation low k dielectric materials. [Display omitted] • Newly designed polymer synthesis protocol containing a PIM skeleton was developed. • Polymers showed excellent thermal, mechanical, optical, and insulating properties. • Tough and transparent films were obtained. [ABSTRACT FROM AUTHOR]

Polymer of intrinsic microporosity (PIM-1) was prepared according to a new procedure – precipitation polycondensation in DMSO solution. The permeability coefficients were determined in the "as cast" and ethanol treated samples of this material. It was shown that permeability of the novel polymer is higher than that of PIM-1 samples prepared according to the traditional methods, while selectivity was lower. Free volume in the novel PIM-1 was studied using the PALS technique. Positron life time parameters and the radii of free volume elements were virtually the same as in PIM-1 samples investigated earlier. The samples of novel PIM-1 were subjected to treatment by supercritical CO 2 and annealing of free films and films in strained state. The treatment with scCO 2 leads qualitatively to the same results as insertion of the films into EtOH (increase in gas permeability) although the observed P i values are somewhat lower. Annealing of the films in strained and free state causes significant decrease in gas permeability with respect to all the gases but increase in selectivity. This effect is rather strong, so some the data points are even located above the Upper Bound 2008 in Robeson diagrams. Aging of PIM-1 samples for 30–60 days was also studied, and its mechanism is considered. Image 1 • Polymer of intrinsic microporosity (PIM-1) was investigated in various states. • The films tested were as cast, ethanol treated, aged, supercritical CO 2 treated and annealed in free and in strained state. • Gas permeability and positron life time parameters were used for characterization of these states of the films. • It was shown how different treatments can be used to control the location of data points above the Upper Bound 2008. [ABSTRACT FROM AUTHOR]

Two novel OH-functionalized intrinsically microporous polymers were successfully synthesized from a tert-butyldimethylsilyl (TBS) protected 1,1′-binaphthalene-diamine monomer (NH 2 -BINOL-TBS). Interestingly, the polymerization and the removal of the TBS to form OH group happened at the same time. Polymers with 30% (PIM-HNTB-30) and 60% (PIM-HNTB-60) OH concentration were obtained by controlling the reaction time of 3.5 and 12 h, and confirmed by nuclear magnetic resonance spectroscopy (NMR). PIM-HNTB-30 exhibited higher Brunauer-Emmett-Teller (BET) surface area (432 vs 153 m2 g-1) and thermal stabilities (420 vs 385 °C) than PIM-HNTB-60. Both membranes showed modest gas permeabilities and selectivities, and PIM-HNTB-60 exhibited a relatively higher performance. After long-term aging or thermally annealed above glass transition temperature (T g), both polymers exhibited a decreased permeabilities combined with a selectivity increase, and the 350 °C treated PIM-HNTB-60 exhibited O 2 permeability of 89 Barrer and O 2 /N 2 selectivity of 4.47. In all, the OH functionalization provided a good way to enhance the gas separation performance. Image 1 • Two OH-functionalized Tröger's base-based ladder polymers were synthesized. • Both polymers showed high thermal stability, molecular weight and modest BET surface areas. • PIM-HNTB-60 with higher OH concentration exhibited a relative better gas separation performance. • Long term aging and thermal annealing above T g resulted in a decreased permeability and increased selectivity. [ABSTRACT FROM AUTHOR]