Synthesis, characterization and gas separation properties of novel copolyimide membranes based on flexible etheric–aliphatic moieties

Khoshkam, Milad; Sadeghi, Morteza; Chenar, Mahdi Pourafshari; Naghsh, Mahdi; fard, Mohammad J. Namazi; Shafiei, Mohammadreza

doi:10.1039/c6ra04973g

Cited by 21 publications

(14 citation statements)

References 54 publications

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“…The X‐ray diffraction (XRD) patterns of polyimides power were taken from 5° to 90° (2 θ value) by Bruker AXS Panalytical using Cu radiation (45 kV, 200 mA, speed: 0.08). The mean intermolecular distances ( d ‐spacing) of polyimides were determined based on the Bragg's law:

n λ = 2 d sin true(θ true)

where d was the d ‐spacing, λ was the wavelength of radiation ( λ = 1.54 Å), θ was the scattering, and n was an integer number (1, 2, 3…). Limited oxygen index (LOI) could be calculated using Van Krevelen and Hoftyzer equation:

LOI true(% true) = 17.5 + 0.4 CR

where CR referred to char yield at 800 °C.…”

Section: Methodsmentioning

confidence: 99%

Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties

Yang

Ding

Xia

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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To better understand the structure–property relationships, two novel aromatic diamines containing tetraphenyl fluorene (TPF) moiety through triphenylamine (TPA) unit and carbazole (Cz) unit modification are designed and synthesized, respectively. Four thermally stable and excellent solubility polyimides are prepared and characterized. The excellent film‐formation ability and thin film stability are investigated by X‐ray diffraction (XRD) and atom force microscopy (AFM) measurements, respectively. The memory devices are fabricated, PIs films with low water uptakes sandwiched between indium‐tin oxide (ITO) ground electrode and Al top electrode, and exhibit nonvolatile write‐once read‐many‐times (WORM) memory behaviors with low threshold voltages, due to increasing the retention time through regulating the energy level. The current conduction mechanisms of all devices are linearly fitted by theoretical conduction model. Molecular simulations are used to demonstrate switching mechanism and the memory effects. The experimental results provide a sight for the design‐adjustable switching voltage of memory devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1630–1644

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n λ = 2 d sin true(θ true)

LOI true(% true) = 17.5 + 0.4 CR

where CR referred to char yield at 800 °C.…”

Section: Methodsmentioning

confidence: 99%

Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties

Yang

Ding

Xia

et al. 2018

J. Polym. Sci. Part A: Polym. Chem.

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“…Various kinds of nanoparticles (SiO 2 , TiO 2 , ZrO 2 , CeO, and ZnO) are commercially available to improve barrier properties of polymeric membranes. [18,21,22] Controlling the free volume in glassy nanocomposite membranes can tailor the permeation properties. Higher free volume facilitates the gas molecule transport through the membrane.…”

Section: Introductionmentioning

confidence: 99%

“…Various kinds of nanoparticles (SiO 2 , TiO 2 , ZrO 2 , CeO, and ZnO) are commercially available to improve barrier properties of polymeric membranes. [ 18,21,22 ]…”

Section: Introductionmentioning

confidence: 99%

Gas separation through polyurethane–ZnO mixed matrix membranes and mathematical modeling of the interfacial morphology

et al. 2020

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A series of polyurethane/ZnO membranes was fabricated via thermal phase inversion of the solution of polymer/nanoparticle in N,N‐dimethylformamide solvent. The polyurethane synthesis was done via two‐step polymerization method using polytetramethylene glycol, isophorone diisocyanate, and 1,4‐butanediol in the ratio of 1:3:2. Different concentrations of zinc oxide nanoparticles (5, 10, 15, and 20) were incorporated into the polyurethane matrix. FTIR, SEM, and X‐Ray analysis were performed to characterize the membranes. FTIR and SEM results suggests an increment in the phase mixing of polyurethane with ZnO loading. Gas permeation performance through polyurethane‐ZnO mixed matrix membranes with ZnO loading by as much as 20 wt% were elucidated for pure N2, O2, CH4, and CO2 and gases. Based on the results, all permeability values decreased as the loading of ZnO nanoparticles increased, whereas CO2/N2 and CO2/CH4 selectivities increased. Moreover, interfacial structure of the polyurethane/ZnO nanocomposites were characterized by molecular probing approach. The results revealed the presence of a rigidified polymer chain layer with 65 ± 6 Å thickness around the ZnO nanoparticles.

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“…Now, many efforts have been made to improve the gas permeability and selectivity of polyimide membranes. [29][30][31][32] Hydroxyl group-containing polyimides (HPIs) can be used as nonlinear optical materials, adhesive, photoresist, alignment layer, and separation materials due to their large electro-optic coefficients, low dielectric constants, hydrophobicity, thermal resistance, reactivity, and flexibility in fabrication. [33][34][35][36][37] Due to the existence of hydroxyl groups, HPI can react with various resin systems, such as epoxy resin, to obtain excellent properties.…”

Section: Introductionmentioning

confidence: 99%

Optical, thermal and gas separation properties of acetate-containing copoly(ether-imide)s based on 6FDA and fluorenyl diamines

Hao

Xiao

et al. 2019

High Performance Polymers

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The diamine, 9,9-bis[4-(4-amino-3-hydroxylphenoxy)phenyl]fluorene (BAHPPF) was synthesized by the modified two-step method. Then, a series of acetate-containing copoly(ether-imide)s were prepared by the copolymerization of BAHPPF, 9,9-bis(4-aminophenyl)fluorene (BAF) and 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) followed by chemical imidization. The structures and properties of the BAHPPF and copoly(ether-imide)s were characterized by nuclear magnetic resonance spectrometer (NMR), Fourier transform infrared spectrometer (FTIR), X-ray diffractometer (XRD), differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), ultraviolet-visible spectrophotometer (UV-VIS), and tensile testing. Single gas permeation performances of these copoly(ether-imide)s were also studied for five representative gases of interest including H2, O2, N2, CO2, and CH4. The experimental results showed that the copoly(ether-imide)s showed excellent optical properties with high light transmittance above 80.2% at 450 nm. The glass transition temperature of these copolymers were higher than 333°C. Their tensile strength and Young’s module also increased, and the elongation decreased with the decrease of BAHPPF. High gas permeabilities of copoly(ether-imide)s were obtained, and the ideal selectivity of CO2/CH4 was improved due to the introduction of acetate group and flexible ether linkage. These copoly(ether-imide)s could be applied to the field of optics and gas separation.

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Synthesis, characterization and gas separation properties of novel copolyimide membranes based on flexible etheric–aliphatic moieties

Abstract: The structural properties and gas permeation of a group of copolyimide membranes were investigated.

Cited by 21 publications

References 54 publications

Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties

Nonvolatile write‐once read‐many‐times memory behaviors of polyimides containing tetraphenyl fluorene core and the pendant triphenylamine or carbazole moieties

Gas separation through polyurethane–ZnO mixed matrix membranes and mathematical modeling of the interfacial morphology

Optical, thermal and gas separation properties of acetate-containing copoly(ether-imide)s based on 6FDA and fluorenyl diamines

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