Greener Synthesis of the Polymer of Intrinsic Microporosity PIM-1 for Gas Separation.

Polymers of intrinsic microporosity (PIMs) are studied as membranes for energy-efficient and environmentally friendly separation technologies, but greener polymerization methods are desirable for further scale up. This work aimed to synthesize the prototypical PIM (PIM-1) via a greener synthetic route by changing the solvent system to methyl-5-(dimethylamino)-2,2-dimethyl-5-oxopentanoate (MDDOP), a structural analogue of the green solvent Rhodiasolv PolarClean. Mass-based green metrics analysis was performed on MDDOP, determining atom economy, complete environmental factor, and total carbon intensity, comparing each to synthetic routes to PolarClean.

Effect of Temperature-Induced Aging on the Gas Permeation Behavior of Thin Film Composite Membranes of PIM-1 and Carboxylated PIM-1.

Polymers of intrinsic microporosity (PIMs) are a class of promising gas separation materials due to their high membrane permeabilities and reasonable selectivities. When processed into thin film composite (TFC) membranes, their high gas throughput aligns closely with industrial requirements, but they are prone to physical aging and plasticization effects. TFC membranes based on the prototypical PIM-1 and its carboxylated derivative cPIM-1 exhibit temperature-dependent gas permeation behavior, which has not been extensively studied before.

Molecular Mobility and Gas Transport Properties of Mixed Matrix Membranes Based on PIM-1 and a Phosphinine Containing Covalent Organic Framework.

Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to their pronounced physical aging. In this study, a covalent organic framework containing λ-phosphinine moieties, CPSF-EtO, was incorporated as a nanofiller (concentration range 0-10 wt %) into a PIM-1 matrix forming dense films with a thickness of ca.

Crosslinking of Branched PIM-1 and PIM-Py Membranes for Recovery of Toluene from Dimethyl Sulfoxide by Pervaporation.

Branched forms of the archetypal polymer of intrinsic microporosity PIM-1 and the pyridinecarbonitrile-containing PIM-Py may be crosslinked under ambient conditions by palladium(II) acetate. Branched PIM-1 can arise in polymerizations of 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethyl-1,1'-spirobisindane with tetrafluoroterephthalonitrile conducted at a high set temperature (160 °C) under conditions, such as high dilution, that lead to a lower-temperature profile over the course of the reaction. Membranes of PIM-1 and PIM-Py crosslinked with palladium acetate are sufficiently stable in organic solvents for use in the recovery of toluene from its mixture with dimethyl sulfoxide (DMSO) by pervaporation at 65 °C.

Methanol Vapor Retards Aging of PIM-1 Thin Film Composite Membranes in Storage.

Physical aging of glassy polymers leads to a decrease in permeability over time when they are used in membranes. This hinders the industrial application of high free volume polymers, such as the archetypal polymer of intrinsic microporosity PIM-1, for membrane gas separation. In thin film composite (TFC) membranes, aging is much more rapid than in thicker self-standing membranes, as rearrangement within the thin active layer is relatively fast.

Sieving gases with twisty polymers.

Ladder polymers in three dimensions show promise as gas-separation membranes.

PIM-1/Holey Graphene Oxide Mixed Matrix Membranes for Gas Separation: Unveiling the Role of Holes.

PIM-1/holey graphene oxide (GO) mixed matrix membranes (MMMs) have been prepared and their gas separation performance for CO/CH mixtures assessed. Nanopores have been created in the basal plane of gas-impermeable GO by chemical etching reactions, and the resulting holey flakes have been further chemically functionalized, either with octadecylamine (ODA) or with PIM-1 moieties, to aid their dispersion in PIM-1. It is found that nanopores barely promote gas transport through the graphene-like nanofiller for fresh membranes (tested right after preparation); however, the prepared hybrid PIM-1/holey GO membranes exhibit higher CO permeability and CO/CH selectivity than the pure polymer membrane 150 days after preparation and 13 and 15% higher CO permeability for filler contents of 0.

High-Flux Thin Film Composite PIM-1 Membranes for Butanol Recovery: Experimental Study and Process Simulations.

Thin film composite (TFC) membranes of the prototypical polymer of intrinsic microporosity (PIM-1) have been prepared by dip-coating on a highly porous electrospun polyvinylidene fluoride (PVDF) nanofibrous support. Prior to coating, the support was impregnated in a non-solvent to avoid the penetration of PIM-1 inside the PVDF network. Different non-solvents were considered and the results were compared with those of the dry support.

Superglassy Polymers to Treat Natural Gas by Hybrid Membrane/Amine Processes: Can Fillers Help?

Superglassy polymers have emerged as potential membrane materials for several gas separation applications, including acid gas removal from natural gas. Despite the superior performance shown at laboratory scale, their use at industrial scale is hampered by their large drop in gas permeability over time due to physical aging. Several strategies are proposed in the literature to prevent loss of performance, the incorporation of fillers being a successful approach.

Boosting gas separation performance and suppressing the physical aging of polymers of intrinsic microporosity (PIM-1) by nanomaterial blending.

In recent decades, polymers of intrinsic microporosity (PIMs), especially the firstly introduced PIM-1, have been actively explored for various membrane-based separation purposes and widely recognized as the next generation membrane materials of choice for gas separation due to their ultra-permeable characteristics. Unfortunately, the polymers suffer substantially the negative impacts of physical aging, a phenomenon that is primarily noticeable in high free volume polymers. The phenomenon occurs at the molecular level, which leads to changes in the physical properties, and consequently the separation performance and membrane durability.

Mitigation of Physical Aging with Mixed Matrix Membranes Based on Cross-Linked PIM-1 Fillers and PIM-1.

A low cross-link density (LCD) network-PIM-1, which offers high compatibility with the polymer of intrinsic microporosity PIM-1, is synthesized by a modified PIM-1 polycondensation that combines both a tetrafluoro- and an octafluoro-monomer. To maximize the advantages of utilizing such cross-linked PIM-1 fillers in PIM-1-based mixed matrix membranes (MMMs), a grafting route is used to decorate the LCD-network-PIM-1 (dispersed phase) with PIM-1 chains, to further enhance compatibility with the PIM-1 matrix. Mixed-gas CO/CH (1:1, v/v) separation results over 160 days of membrane aging confirm the success of a relatively short (24 h) grafting reaction in improving the initial CO separation performance, as well as hindering the aging of PIM-1/grafted-LCD-network-PIM-1 MMMs.

Intrinsically Microporous Polymer Nanosheets for High-Performance Gas Separation Membranes.

Microporous polymer nanosheets with thicknesses in the range 3-5 nm and with high apparent surface area (Brunauer-Emmett-Teller surface area 940 m g ) are formed when the effectively bifunctional (tetrafluoro) monomer used in the preparation of the prototypical polymer of intrinsic microporosity PIM-1 is replaced with an effectively tetrafunctional (octafluoro) monomer to give a tightly crosslinked network structure. When employed as a filler in mixed-matrix membranes based on PIM-1, a low loading of 0.5 wt% network-PIM-1 nanosheets gives rise to enhanced CO permeability and CO /CH selectivity, compared to pure PIM-1.

Effect of Backbone Rigidity on the Glass Transition of Polymers of Intrinsic Microporosity Probed by Fast Scanning Calorimetry.

Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships, including physical aging. In this context, the glass transition plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs before their thermal decomposition.

Gas Permeation Properties, Physical Aging, and Its Mitigation in High Free Volume Glassy Polymers.

Hundreds of polymers have been evaluated as membrane materials for gas separations, but fewer than 10 have made it into current commercial applications, mainly due to the effects of physical aging and plasticization. Efforts to overcome these two problems are a significant focus in gas separation membrane research, in conjunction with improving membrane separation performance to surpass the Robeson upper bounds of selectivity versus permeability for commercially important gas pairs. While there has been extensive research, ranging from manipulating the chemistry of existing polymers (e.

First Clear-Cut Experimental Evidence of a Glass Transition in a Polymer with Intrinsic Microporosity: PIM-1.

Polymers with intrinsic microporosity (PIMs) represent a novel, innovative class of materials with great potential in various applications from high-performance gas-separation membranes to electronic devices. Here, for the first time, for PIM-1, as the archetypal PIM, fast scanning calorimetry provides definitive evidence of a glass transition ( T = 715 K, heating rate 3 × 10 K/s) by decoupling the time scales responsible for glass transition and decomposition. Because the rigid molecular structure of PIM-1 prevents any conformational changes, small-scale bend and flex fluctuations must be considered the origin of its glass transition.

Anomalies in the low frequency vibrational density of states for a polymer with intrinsic microporosity - the Boson peak of PIM-1.

Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, the vibrational density of states (VDOS) for PIM-1, the prototypical polymer with intrinsic microporosity, is investigated by means of inelastic neutron scattering. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid).

Poly(vinylphosphonic acid-co-acrylic acid) hydrogels: The effect of copolymer composition on osteoblast adhesion and proliferation.

There is a clinical need for a synthetic bone graft substitute that can be used at sites of surgical intervention to promote bone regeneration. Poly(vinylphosphonic acid-co-acrylic acid) (PVPA-co-AA) has recently been identified as a potential candidate for use in bone tissue scaffolds. It is hypothesized that PVPA-co-AA can bind to divalent calcium ions on bone mineral surfaces to control matrix mineralization and promote bone formation.

The unique calcium chelation property of poly(vinyl phosphonic acid-co-acrylic acid) and effects on osteogenesis in vitro.

There is a clear clinical need for a bioactive bone graft substitute. Poly(vinyl phosphonic acid-co-acrylic acid) (PVPA-co-AA) has been identified as a promising candidate for bone regeneration but there is little evidence to show its direct osteogenic effect on progenitor or mature cells. In this study mature osteoblast-like cells (SaOS-2) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) were cultured with PVPA-co-AA polymers with different VPA:AA ratio and at different concentrations in vitro.

Synthesis and Transport Properties of Novel MOF/PIM-1/MOF Sandwich Membranes for Gas Separation.

Metal-organic frameworks (MOFs) were supported on polymer membrane substrates for the fabrication of composite polymer membranes based on unmodified and modified polymer of intrinsic microporosity (PIM-1). Layers of two different MOFs, zeolitic imidazolate framework-8 (ZIF-8) and Copper benzene tricarboxylate ((HKUST-1), were grown onto neat PIM-1, amide surface-modified PIM-1 and hexamethylenediamine (HMDA) -modified PIM-1. The surface-grown crystalline MOFs were characterized by a combination of several techniques, including powder X-ray diffraction, infrared spectroscopy and scanning electron microscopy to investigate the film morphology on the neat and modified PIM-1 membranes.

Selective dye adsorption by chemically-modified and thermally-treated polymers of intrinsic microporosity.

Nitrile groups in the polymer of intrinsic microporosity PIM-1 were modified by base-catalysed hydrolysis, by reaction with ethanolamine and diethanolamine, and by reduction to amine, and the products investigated for their ability to take up a range of dyes from aqueous or ethanolic solution. Hydrolysed products exhibited selectivity for cationic over anionic species, while other products showed the reverse selectivity. At low pH, amine-PIM-1 adsorbed more than its own weight of the anionic dyes Orange II and Acid Red I from aqueous solution.

Molecular Mobility of the High Performance Membrane Polymer PIM-1 as Investigated by Dielectric Spectroscopy.

The increasing demand for energy efficient separation processes fosters the development of new high performance polymers as selective separation layers for membranes. PIM-1 is the archetypal representative of the class of polymers of intrinsic microporosity (PIM) which are considered most promising in this sector, especially for gas separations. Since their introduction, PIMs stimulated a vast amount of research in this field and meanwhile evolved to the state-of-the-art in membrane technology for gas separation.

PIM-1 mixed matrix membranes for gas separations using cost-effective hypercrosslinked nanoparticle fillers.

High-free-volume glassy polymers, such as polymers of intrinsic microporosity (PIMs) and poly(trimethylsilylpropyne), have attracted attention as membrane materials due to their high permeability. However, loss of free volume over time, or aging, limits their applicability. Introduction of a secondary filler phase can reduce this aging but either cost or instability rules out scale up for many fillers.

The influence of few-layer graphene on the gas permeability of the high-free-volume polymer PIM-1.

Gas permeability data are presented for mixed matrix membranes (MMMs) of few-layer graphene in the polymer of intrinsic microporosity PIM-1, and the results compared with previously reported data for two other nanofillers in PIM-1: multiwalled carbon nanotubes functionalized with poly(ethylene glycol) (f-MWCNTs) and fused silica. For few-layer graphene, a significant enhancement in permeability is observed at very low graphene content (0.05 vol.

Enhancement of CO Affinity in a Polymer of Intrinsic Microporosity by Amine Modification.

Nitrile groups in the polymer of intrinsic microporosity PIM-1 were reduced to primary amines using borane complexes. In adsorption experiments, the novel amine-PIM-1 showed higher CO uptake and higher CO/N sorption selectivity than the parent polymer, with very evident dual-mode sorption behavior. In gas permeation with six light gases, the individual contributions of solubility and diffusion to the overall permeability was determined via time-lag analysis.