Comparison of Impact of Virgin Polymer Structure on Properties of Irradiated Membranes – Hydrogen Ion Irradiation on Polyimide Isomers

2002 ◽  
Vol 752 ◽  
Author(s):  
Xinglong Xu ◽  
Ling Hu ◽  
J. Ilconich
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Composite Membranes ◽  
Polymer Structure ◽  
Gas Permeation ◽  
Ion Beam Modification ◽  
Wide Range ◽  
The Impact

ABSTACTThis study focused on the impact of virgin polymer structure and microstructure on the transport properties of irradiated polyimide. Two fluorine containing polyimide isomers (6FDA-6FpDA and 6FDA-6FmDA) that differ solely in the location of the linkage between the diamine and dianhydride residues were used for this study. While these polymers differ in the location of a single bond, the virgin transport properties are dramatically different. The para connected isomer (6FDA-6FpDA) has much higher permeabilities and lower selectivities than the meta connect isomer (6FDA-6FmDA). The pure gas permeabilities in polyimide-ceramic composite membranes following H+ ion irradiation over a wide range of doses will be compared for these polyimide isomers. In addition, the evolution in chemical structure was monitored using Fourier transform infrared spectroscopy (FTIR). These polymers exhibited different decay rate in chemical structure following ion irradiation. Interestingly, the evolution in gas transport properties of these polymers following H+ ion irradiation was also quite different. We will discuss how the microstructure would affect the gas permeation properties of ion beam modification of polymer.

Ion Beam Modification of Matrimid® Gas Separation Membrane—Evolution in Chemical Structure, Microstructure and Gas Permeation Properties

2002 ◽  
Vol 752 ◽  
Author(s):  
Xinglong Xu ◽  
Ling Hu ◽  
Maria Coleman
Keyword(s):  
Transport Properties ◽  
Chemical Structure ◽  
Gas Transport ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Gas Permeation ◽  
Ion Beam Modification ◽  
Gas Transport Properties ◽  
Wide Range ◽  
Permeation Properties

ABSTRACTMatrimid® is a widely used polyimide that has both attractive thermal and gas transport properties. In addition, it has been used as a precursor polymer for production of carbon molecular sieving membranes with commercially interesting gas separations. Ion beam irradiation over a wide range of doses was used to modify a series of Matrimid® membranes. A combined analysis of impact of ion irradiation on the chemical structure, microstructure and gas transport properties of Matrimid® will be presented. Specifically, the evolution in gas permeation properties following irradiation over a wide range of doses will be discussed. Ion irradiation resulted in combined increased permeability and permselectivity for several gas pairs of interest.

Ion Beam Irradiation—An Efficient Method to Modify The Subnanometer Scale Microstructure of Polymers In A Controlled Way

1998 ◽  
Vol 540 ◽  
Author(s):  
Xinglong Xu ◽  
M. R. Coleman ◽  
U. Myler ◽  
P. J. Simpson
Keyword(s):  
Ion Irradiation ◽  
Gas Permeability ◽  
Ion Beam ◽  
Composite Membranes ◽  
Positron Annihilation Spectroscopy ◽  
Gas Permeation ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Application Potential ◽  
Promising Application

AbstractThe microstructural evolution of polymers induced by ion beam irradiation was investigated using gas permeation measurements with different molecule size gases and positron annihilation spectroscopy (PAS) using variable-energy positron. Simultaneous large increases in gas permeability and permselectivity of polymer-ceramic composite membranes modified by 180 keV H+ ion irradiation indicated that ion irradiation of polymers can modify the microstructure of polymer at sub-nanometer level in a controlled way. PAS results were consistent with the gas permeation results. The results of this work demonstrated ion beam irradiation has a promising application potential in the separation industry.

scholarly journals Ion Beam Modification of PVDC and Pe Polymers

1995 ◽  
Vol 396 ◽  
Author(s):  
A. L. Evelyn ◽  
D. Ila ◽  
J. Fisher ◽  
D. B. Poker
Keyword(s):  
Chemical Structure ◽  
Microprobe Analysis ◽  
Ion Beam ◽  
Electronic Energy ◽  
Alpha Particles ◽  
Stopping Power ◽  
Nuclear Stopping ◽  
Resistivity Measurements ◽  
Ion Beam Modification ◽  
Raman Microprobe

AbstractThe electronic and nuclear stopping effects produced by MeV ion bombardment in polyvinylidine chloride (PVDC) and polyethylene (PE) are separated by stacking thin films of the polymers. The resulting multi-layer laminates of each polymer were bombarded with 3.5 MeV alpha particles. The energy of the incident ions was selected, using TRIM, such that the first layers experienced most of the effects of the electronic energy deposited and the last layers received most of the effects of the nuclear stopping power. The changes in the conductance and the chemical structure of each layer were measured by direct resistivity measurements and Raman microprobe analysis.

Effective Hydrogen Separation Using Ion Beam Modified Polymeric Membranes

2002 ◽  
Vol 756 ◽  
Author(s):  
M. R. Coleman ◽  
X. Xu ◽  
J. Ilconich ◽  
J. Ritchie ◽  
L. Hu
Keyword(s):  
High Purity ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Hydrogen Permeability ◽  
Primary Energy ◽  
Hydrogen Separation ◽  
Hydrogen Gas ◽  
Polymeric Membranes ◽  
Chemical Attack ◽  
The Impact

ABSTRACTHigh purity H2 gas streams are increasingly important for a variety of applications including feed gases for fuel cells. The potential of hydrogen gas as primary energy source has generated considerable interest in hydrogen separation technologies. We have been investigating ion beam irradiation as a method to modify polymeric membranes to enhance both hydrogen permeability and permselectivities. Combined high permeabilities and permselectivities are required to give high recoveries of high purity hydrogen. Ion irradiation typically results in the formation of numerous crosslinks within the polymer matrix that should enable these materials to maintain selectivities at high temperatures and to resist chemical attack. Helium separations over a range of temperatures of irradiated polyimides were used as a model of the hydrogen system. Finally, the impact of irradiation conditions on gas separations in these materials will be addressed.

Ion Beam Modification of TI-Ba-Ca-Cu-O Type High Temperature Superconductors During Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
P.P. Newcomer ◽  
L. M. Wang ◽  
B. Morosin
Keyword(s):  
High Temperature ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Ion Beam Modification ◽  
Moiré Fringes ◽  
High Resolution Tem ◽  
20 Nm ◽  
Induced Crystallization

AbstractMicrostructural modification of high temperature superconductor (HTS) single-crystal plates of T1-1212 and T1-2212 (numbers designate the Tl/Ba/Ca/Cu cation ratio) was studied during 1.5 MeV Kr+ and Xe+ ion irradiation with in-situ electron diffraction and after ion irradiation with high resolution TEM (HRTEM). Similar in-situ temperature dependence effects are seen for both phases. During irradiations from 22K to 673K, an amorphous halo develops after very low ion dose or fluence (l.7X1012 ions/cm2). During irradiation at 100K and 300K, complete amorphization is obtained, while at 22K and ≥533K, the halo fades slightly and a polycrystalline ring pattern develops, indicating ion irradiation induced crystallization occurred. After a low ion dose (8.5XlO12ions/cm2) at 100K and 300K, HRTEM reveals amorphous regions 5 -20 nm in size which are not columnar and do not all penetrate the entire sample thickness. At 22K and ≥533K, Moire fringes and misoriented crystallites of cascade size are observed. The 4 - 6nm crystallites are thallium-rich.

Identification of Fragile Microscopic Structures during Mineral Transformations in Wet Supercritical CO2

2013 ◽  
Vol 19 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Bruce W. Arey ◽  
Libor Kovarik ◽  
Odeta Qafoku ◽  
Zheming Wang ◽  
Nancy J. Hess ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Water Content ◽  
Ion Beam ◽  
Magnesium Carbonate ◽  
Interfacial Structure ◽  
Reaction Products ◽  
Wide Range ◽  
Key Factor ◽  
Mineral Transformations ◽  
The Impact

AbstractThis study examines the nature of highly fragile reaction products that form in low water content supercritical carbon dioxide (scCO2) using a combination of focus ion beam/scanning electron microscopy, confocal Raman spectroscopy, helium ion microscopy (HeIM), and transmission electron microscopy (TEM). HeIM images show these precipitates are fragile rosettes. Using the TEM revealed details on the interfacial structure between the newly formed surface precipitates and the underlying initial solid phases. Detailed microscopy analysis revealed that growth of the precipitates either followed a tip growth mechanism, with precipitates forming directly on the forsterite surface if the initial solid was nonporous (natural forsterite) or growth from the surface of the precipitates, where fluid was conducted through the porous (nanoforsterite) agglomerates to the growth center. Identification of the mechanism of formation of hydrated/hydroxylated magnesium carbonate compound phases is a key factor in unraveling the impact of water recycling on mineral reactivity in low water content scCO2 solutions, which has received a great deal of attention as a result of the potential for CO2 to act as an atmospheric greenhouse gas. Techniques used here to examine these fragile structures are also used to examine a wide range of fragile material surfaces.

Ion Beam Modification of High-Tc Superconductors

1989 ◽  
Vol 157 ◽  
Author(s):  
O. Meyer ◽  
J. Geerk ◽  
T. Kroner ◽  
Q. Li ◽  
G. Linker ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ion Irradiation ◽  
Ion Beam ◽  
High Temperature Superconductors ◽  
Lattice Parameter ◽  
Ion Beam Modification ◽  
Radiation Induced ◽  
Htsc Thin Films ◽  
Property Changes ◽  
Induced Changes

ABSTRACTIon irradiation and implantation experiments of high temperature superconductors (HTSC) thin films resulted in many interesting effects. Among those are: (i) the superlinear increase of the resistivity, p, with ion fluence, φ, leading to a metal to insulator transformation, (ii) the large recovery above 150 K of the radiation induced changes of ρ and Tc observed in low temperature irradiation experiments, and (iii) the large structural changes such as the increase of the c-axis lattice parameter with φ, the radiation induced orthorhombic to tetragonal phase transition, and the amorphization. Displaced oxygen atoms play an important role for the observed property changes.

scholarly journals Enhancing Gas Permeation Properties of Pebax® 1657 Membranes via Polysorbate Nonionic Surfactants Doping

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 253 ◽  
Author(s):  
Paola Bernardo ◽  
Gabriele Clarizia
Keyword(s):  
Transport Properties ◽  
Nonionic Surfactants ◽  
Gas Transport ◽  
Carbon Oxide ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Effect Of Temperature ◽  
Membrane Morphology ◽  
Gas Transport Properties ◽  
The One

Composite membranes were prepared by co-casting, incorporating two nonionic surfactants in a poly(ether-block-amide), Pebax® 1657 up to 50 wt %. These polysorbate nonionic surfactants contain many ethylene oxide units and are very CO2-philic agents; thereby, they can be exploited as membrane additives for gas separation involving carbon oxide. Dynamic light scattering analysis proved a higher stability of additionated Pebax® 1657 solutions with respect to those containing only the copolymer. Scanning electron microscopy showed a regular membrane morphology without pores or defects for all investigated samples. If on the one hand the addition of the additive has depressed the mechanical properties, on the other, it has positively influenced the gas transport properties of Pebax® 1657 films. CO2 permeability increased up to two or three times after the incorporation of 50 wt % additive in copolymer matrix, while the selectivity was not significantly affected. The effect of temperature on permanent gas transport properties was studied in the range of 15–55 °C.

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