ABSTRACTS

The following is a list of the abstracts for papers which will be presented in THE SIXTH INTERNATIONAL SYMPOSIUM ON POLYIMIDES AND OTHER HIGH TEMPERATURE/HIGH PERFORMANCE POLYMERS: SYNTHESIS, CHARACTERIZATION AND APPLICATIONS. The listing is alphabetical by presenting author. This list is updated continually to add abstracts as they become available and make appropriate corrections. This list may be conveniently searched by using the editor provided with most popular browsers (e.g. Microsoft Explorer, Netscape, Firefox ... etc.)

M. Akram, S. Bhowmik, R. Benedictus and J. A. Poulis; Aerospace Materials and Structures, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, THE NETHERLANDS

Surface Modification of Polyimide by Atmospheric Pressure Plasma for Adhesive Bonding with Titanium and its Application to Aviation and Space

It is noted that in search of long term and efficient service performance in the context of future generation of aerospace materials, there is increasing need of metal-high performance polymer composite. Based on these considerations, high temperature resistant polymeric sheet such as Polyimide Meldin7001 sheet, joined with Titanium sheet by employing ultra high temperature resistant Polyimide adhesive.

In order to increase surface energy of Polymide surface, atmospheric pressure plasma treatment is used to modify Polyimide surface. Atmospheric pressure plasma treatment creates physical and chemical changes such as crosslinking, formation of free radicals and oxygen functionalisation in the form of polar groups on polymer surface resulting in improvement of wetting and adhesion characteristics. Surface of Polyimide (PI) sheet. is treated with atmospheric pressure plasma for different exposure periods .Surface energy of PI sheet increases with increase in exposure time. However, after a certain exposure time of plasma, results deterioration of surface layer of PI substrate resulting in degradation and embitterment of PI which is not suitable for adhesive bonding. Optical microscopic, SEM (EDS), XPS and AFM analysis of treated and untreated specimen is carried out to examine the surface characteristics. Treated samples and untreated samples of Polyimide are bonded together with overlap joints. Lap shear bond strength of treated and untreated samples was measured by tensile test to study the effect of treatment on adhesive bond strength. The optimized time of plasma treatment suggested in this investigation results maximum adhesive bond strength and consequently, this technology is highly acceptable for aviation and space applications.

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Wai Kin Chan; Department of Chemistry, The University of Hong Kong

Pokfulam Road, Hong Kong, CHINA

Synthesis of Metal Containing Aromatic Polyamides and Polyesters and Their Properties

Aromatic polyamides have been used extensively in many important areas as high strength and high temperature materials. Most of the aromatic polyamides reported to date are pure organic materials. In this work, we have synthesized different series of aromatic polyamides and polyesters based using 2,2’-bipyridine dicarboxylic acid as one of the monomers. Some polymers synthesized exhibited high thermal stability with thermal decomposition temperature of 500 ̊C. It was found that some polyamides with rigid main chain formed lyotropic mesophases when dissolved in concentrated sulfuric acid or HMPA-4 % LiCl solvent systems. For those polyamides and polyesters with more flexible main chain, thermotropic liquid crystal phase was observed. The bipyridine moieties are able to form coordination complexes with ruthenium or other transition metals. These polymer ruthenium complexes were synthesized by either metalation of the polymers or directly from the corresponding ruthenium containing monomer. After the formation of ruthenium complexes, they were able to enhance the photosensitivity and charge carrier mobility of the polymers.

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 Myeon-Cheon Choi¹, Junji Wakita,² Sinji Ando,² and Chang-Sik Ha^*1

1) Department of Polymer Science and Engineering, Pusan National University, Busan 609-735, Korea,

2) Department of Chemistry and Materials Science, Tokyo Institute of Technology, Ookayama 2-12-1-S1-21, Meguro-Ku, Tokyo 152-8552, Japan

Highly Transparent and Refractive Polyimides with Controlled Molecular Structure by Chlorine Side Groups

Transparent polyimides (PIs) that exhibit high refractive index and low birefringence as well as good thermal and mechanical stability were newly synthesized by judicious introduction of di- and tetra-chlorinated aromatic diamines with aromatic/aliphatic dianhydrides. All the PI films, except for the PI derived from aromatic dianhydride and dichlorinated diamine (BPDA/2DCDB and BPDA/3DCDB), exhibit high optical transparency in the whole visible region. In particular, tetra-chlorinated fully aromatic polyimide (BPDA/TCDB) with highly distorted conformation of the main chain endows excellent optical transparency in the visible range comparable to highly fluorinated aromatic PIs, due to the effective suppression of intramolecular charge transfer (CT) interactions. It is for the first time that a high transmittance of 82 % at 400 nm with an average transmittance of higher than 90 % in the visible region as well as very strong fluorescent emission are observed in a fully aromatic PI (BPDA/TCDB). In addition, high average refractive indices (1.702 ~ 1.732), high enough to apply as an optical material such as micro-lens, and low birefringences (0.028 ~ 0.091) were also observed at a wavelength of 633 nm for the chlorinated aromatic PIs

* (Corresponding Author)

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Dong-Hee Park and Won-Kook Choi; Thin Film Materials Research Center, Korea Institute of Science and Technology, Cheongryang P.O Box 131, Seoul 130-650, KOREA

Superhydrophilicity of Polyimide Surface Using Direct Reactive High Flux Low Energy Ion Beam Irradiation

In order to make adhesiveless flexible copper clad laminate (FCCL) for chip-on-flex (COF), vacuum web sputtering system equipped with low energy ion beam pretreatment was installed and deposition of Cu on PI (Kapton-EN) films was carried out. A 300 mm wide linear electron Hall drift ion source with long anode, firstly designed and assembled by our own technique, is adopted for surface modification of PI. When O₂⁺ or N₂O⁺ ion beam with energy of 180 eV was irradiated on PI, the wetting angle was decreased below 2^o at the very short time less than 2 sec from 78^o for pristine PI. From the x-ray photoelectron spectroscopy, a large increment of C=O was clearly observed in the modified PI surface and which well explain the superhydrophilicity and the increase of surface energy of PI. After deposition of thick Cu layer ca. 8 micrometer, adhesion between Cu and PI was investigated in terms of Cu bonding with induced hydrophilic group. Peel strength and aging test of fabricated FCCL will be discussed and also the status of developing linear ion source as long as 1,000 mm will be introduced.

This work is partially supported by Seoul R&BD Program (10848).

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Thuy D. Dang ^1*, Zongwu Bai², Narayanan Venkat², Alexander B. Morgan², Joseph A. Shumaker² and Marlene D. Houtz²

1) AFRL/RXBN, 2941 Hobson Way, Wright-Patterson Air Force Base, Dayton, OH 45433, USA

2) University of Dayton Research Institute, 300 College Park Drive, Dayton OH 45469, USA

*thuy.dang@wpafb.af.mil

Novel Rigid-rod Random Copolymers with Fexibilizing Structural Units for Enhanced Flame Resistance and Blast Protection

The design, synthesis and characterization of novel rigid-rod random copolymer variants of PBO (poly (p-phenylenebenzobisoxazole)) and DiOH-PBO (poly(2,5-dihydroxy-1,4-phenylenebenzobisoxazole)) from the viewpoint of enhanced flame resistance and blast protection in fire-protective clothing applications are described. The structural motif consists of incorporation of flexibilizing hexafluoroisopropylidene (6F-) units in controlled proportions in the rigid-rod polymer backbone to allow for use in fiber applications without causing detriment to the outstanding thermal and mechanical properties of PBO. The introduction of 10 mole % of the “kink” in the stiff-chain polymer structure was not found to affect the formation of the lyotropic mesophase of the rigid-rod polymer in the polymerization medium. Flammability results from Micro-Combustion Calorimetry showed that the copolymers exhibited lower heat release capacity (potential for ignition and heat release) than control PBO samples. In particular, the random copolymer containing the DiOH-PBO structural unit showed an exceptionally low peak heat release capacity (HRC), indicating superior flame resistance properties. The continuous monofilament fibers spun at high draw ratios showed exceptional axial tensile properties and a very low elongation (~ 1-2 %) characteristic of the stiff-chain polymer. However, the desired elongation-at-break (≥ 5 %) for blast protection could not be achieved in these copolymer fibers. To address this issue, a tailorable rigid-rod ABA block (coil-rod-coil) copolymer approach is described for potentially enhancing the breaking strain in such polymer fibers.

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Zeba Parkar and James Economy; Department of Materials Science and Engineering, University of Illinois, at Urbana-Champaign, Urbana, IL 61801

Design of Advanced Aromatic Copolyesters for Aerospace Applications

In the last several years we have taken our earlier work on development and commercialization of the homopolyester Ekonol, and the copolyester, Xydar into a new direction namely the preparation of aromatic thermosetting copolyesters with a number of unique features. As expected this new thermoset displays long term oxidation resistance at 350̊C in air and 450̊C in nitrogen. During curing, the polymer will generate several percent of acetic acid as volatile material which can lead to some microporosity. We have found that we can achieve very low levels of porosity by heating at 325̊C under modest pressure to consolidate the composite through interchain transesterification reactions. Problems related to mismatch of CTE between the carbon fiber reinforcement and the matrix are sharply reduced due to the liquid crystal structure of the thermosetting resin. Since the resin is derived from a mix of monomers including p-hydroxybenzoic acid, trimesic acid, hydroquinone diacetate and isophthalic acid, the rod-like character at least over short distance is sufficient to form a liquid crystalline phase. This tendency is further enhanced by the presence of highly anisotropic carbon fibers which orient the liquid crystalline resin to further reduce interfacial stresses. Another important advantage of this new resin is its outstanding flame and ablative resistance with LOI values approaching numbers such as 0.70 and char values of 40-45%. As a part of the introduction and as time permits I will try and touch on several topics of potential interest including C-fibers/BN matrix composites for use as low wearing aircraft brakes and preparation of single crystal flakes of AlB2 with high aspect ratio of 300/1 as a potential planar reinforcement for aluminium .

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Alexander Fainleib ¹, Olga Grigoryeva¹, Angelika Menner² and Alexander Bismarck²

1) Institute of Macromolecular Chemistry of the National Academy of Sciences of Ukraine, Kyiv, UKRAINE

2) Chemical Engineering, Polymer & Composite Engineering Group, Imperial College London, UK

E-mail: fainleib@i.kiev.ua

High Temperature/High Performance polyHIPEs Based on Polystyrene/Polycyanurate IPNs

In recent years high internal phase emulsions (HIPEs) with a continuous organic phase consisting of monomers, crosslinker and an emulsifier gained increasing interest. HIPEs are commonly defined as emulsions in which the dispersed phase occupied more than 74% of the emulsion volume, i.e. more than the maximum packing fraction for identical spheres. The polymerisation of the monomer phase of the emulsion, which can be oil or aqueous phase, leads to the formation of highly porous (up to 95%) low density polymer foams, so called polyHIPEs. Two kinds of polystyrene/polycyanurate foams with the structure of IPNs, sequential and in situ sequential have been synthesized using HIPE approach. In a first method polystyrene/tri(oxyethylene)-a,w-dimethacrylate foam formed at 75 ^oC during 24 h was swelled by dicyanate ester of bisphenol E (up to 30 wt. %) and then cured step by step at 150-250 ^oC during 15 h. In a second method all the components were mixed together and polystyrene network was obtained first and then the polycyanurate network was synthesized inside the polystyrene foam using the same temperature/time schedule. The final polyHIPEs from polystyrene/polycyanurate IPNs are characterized by higher thermal stability compared to the pure polystyrene foam.

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Scott Jolley¹, Tracy Gibson¹, Lilliana Fitzpatrick¹, and Martha Williams¹²

1) ASRC Aerospace Corporation, Kennedy Space Center, FL 32899

2) NASA, John F. Kennedy Space Center, FL 32899

Physical Properties of Low Melt Polyimides for Aerospace Applications

Polyimides have been used in many applications requiring superb thermal stability, good chemical resistance, and excellent mechanical and electrical properties. These applications include electrical wire insulation, high temperature adhesives, and non-metallic mechanical parts. One of the limiting factors in expanding their use is that these polymers are often difficult to process. We have discovered that through chemical modification to the polymer structure that these typically hard to process polymers can be designed to melt at temperatures compatible with conventional processing techniques. A wide variety of testing has been performed on these newly developed materials, including environmental and chemical exposure, as well as electrical property evaluation. This paper will describe the physical testing of these novel low melt polyimides and compare the results to more conventional polyimides such as Kapton^®.

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Jude. O. Iroh ¹, Jandro Abot², Harikrishna Boddu², Huabin Wang³, Marlene Hourz³, Loon-Seng Tan² and Gary Price³

1) Department of Chemical and Materials Engineering, Department of Aerospace Engineering, University of Cincinnati, Cincinnati, Ohio 45221-0012

2) Manufacturing and Materials Directorate, Polymer Branch, MLBP/AFRL, WPAFB, OH

3) University of Dayton Research Center, UDRI, Dayton, OH

Damping Behavior of Carbon Nanofiber/Polyimide Nanocomposites

The damping behavior and transition temperature of carbon nanofiber/polyimide composite films was investigated. The neat polyimide film showed three transition temperatures as follows; (i) a high glass transition temperature (a) with a sharp and strong transition peak between 398-430˚C and (ii) a low temperature transition with a weak and broad peak (g) at 80-100˚C and (iii) an intermediate transition temperature with a weak and broad transition peak between the a and g transition temperature at 150-180˚C. The temperature of the a transition for the nanocomposites ranged from 425-450˚C for nanocomposites containing about 38% nanofibers to 398˚C for the nanocomposites containing about 0.3% nanofibers. The dynamic mechanical analysis, DMA, trace for multiwalled carbon nanotube/polyimide composite film showed two major transition temperatures at about 180˚C and 450˚C, which are believed to be due to the glass-rubber transition for poly(amic acid) and polyimide units, respectively, contained in the polymer chain. The glass transition temperature for the neat poly(amic acid) film varied from about 120˚C to 180˚C.

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Jude O. Iroh ¹, Wenchao Zhang¹, and Esther Obonyo²

1) Department of Chemical and Materials Engineering, University of Cincinnati Cincinnati, Ohio 45221-0012

2) Department of Building and Construction Engineering, University of Florida, Gainsville, Florida

Hybrid Montmorillonite Clay/Polyimide Nanocomposite Membranes

Clay/polyimide nanocomposite membranes and coatings were prepared by solution casting and cured a temperatures ranging from 70˚C to 100 ˚C. The weight percent of neat organo clay and surface modified organo clay was varied from 0.05 to 2.0%. Diffusion of water through the composite membrane was performed in a U-shaped diffusion cell with two vertical capillary tubes bonded to a cylindrical chamber. The chambers are separated from each other, by using the polyimide membrane. One of the chambers is filled with water while the other contained ethanol/water mixture (5/95, v/v). Diffusion test was performed for about five days to fourteen days.

The diffusion of water occurred from the water rich column into the water ethanol chamber. Permeation of water was very slow in the polyimide membranes imidized at a higher temperature (T>100˚C). The flux through the membranes increased with increased weight percent of clay up to 0.25% clay loading beyond which a drastic decrease in the flux occurred. Our result suggests that polyimide nanocomposite membranes can be used in the separation of ethanol produced during fermentation of carbohydrates.

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J. R. Johnson and W. J. Koros; School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA

Torlon® (polyamide-imide) Nanocomposites Containing Laponite® RD Nanoclays for Barrier Membrane Applications

Polymer nanocomposites containing high aspect ratio fillers (e.g. layered silicates) have received significant attention for several decades. These composites offer improved thermal and mechanical properties compared to pure polymer for casting and molding applications. Additionally, these components offer attractive barrier properties in film and coating applications. Incorporating nanoplatelet materials requires a high degree of exfoliation and complete particle dispersion to achieve optimal transport properties. We have identified an alternative to traditional melt-blending or in-situ polymerization techniques. Our membranes were produced using a solution blending procedure that is favorable for high Tg polymers and does not require pre-treatment of the nanoclays filler. Our work is focused on the production of barrier membranes using a high performance polyamide-imide (Torlon®) polymer matrix and nanoclays (Laponite® RD). Torlon® was chosen because it has an intrinsically low permeability and a high glass transition temperature (Tg = 270̊C). Laponite® RD was chosen as the inorganic filler because its geometry (D < 100nm) is favorable for composites that require a high degree of optical clarity. In this presentation we will review the processing techniques used to form these barrier membranes. Moreover, we will discuss the transport properties of the membranes and compare these results with common transport models.

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Scott Jolley¹, Tracy Gibson¹, Lilliana Fitzpatrick¹, and Martha Williams²

1) ASRC Aerospace Corporation, Kennedy Space Center, FL 32899

2) NASA, Polymer and Chemical Analysis Branch, NE-L6, Kennedy Space Center, FL 32899

Low Melt Polyimides for Repair and Coatings

Polyimides such as Kapton© have been used for decades where a number of high performance parameters are required. One such usage is in the area of electrical wire insulation. Polyimide based insulation delivers outstanding thermal stability, flammability, chemical resistance, and electrical properties. Over time, polyimide based insulation has been shown to slowly succumb to hydrolysis based degradation. Such degradation results in stress induced ring cracking and other insulation failures. A significant amount of polyimide based insulation is present in many older aerospace, military and commercial vehicles and aircraft. NASA space shuttles themselves each contain over 150 miles of such insulated wires. Presently approved methods of repairing such insulation are bulky, cumbersome, and often contribute to further damage to the aging wire insulation. Research directed towards improving the present method of polyimide wire insulation repair has lead to the development of a number of low-melt polyimides that can be crafted into wrappable films/sleeves and effectively employed to repair damaged wire insulation. This low-melt polyimide technology has also been evaluated in preliminary testing as a new coating resin applied to metal surfaces via a powder coating technique.

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Anne Jonquieres, Ismail Ben Youssef, Halima Alem, Frederic Sarry and Omar Elmazria; Laboratoire de Chimie Physique Macromoleculaire, ENSIC, B.P. 20451, F-54001 Nancy, FRANCE

New Polyurethaneimides Containing Lewis Bases for Gas Microsensor Applications

Both microelectronic and medical applications monitor gases and contaminants. For these applications, surface acoustic wave (SAW) gas microsensors are very promising because they are cheap and very easy to implement. Our main purpose is to develop new gas microsensors with selective polymer top layers to obtain particularly high sensor characteristics. The work we are currently developping on this new topic associates the synthesis and characterization of new film-forming polyurethaneimides containing Lewis groups with different basicities, the investigation of their film-forming ability (we have already obtained layers as thin as 200 nm on silicium wafers with these new polymers) and their application for the detection of acid gases with SAW microsensors in collaboration with colleagues who are experts in this new challenging field.

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E. T. Kang ¹, C. X. Zhu ² and K. G. Neoh ¹

1) Dept. of Chemical & Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260 

2) Dept. of Electrical & Computer Engineering, National University of Singapore, Kent Ridge, Singapore 119260 

E-mail: cheket@nus.edu.sg

Electrical Bistability and Random Access Memory Effects in Functionalized Polyimides

Polymer and organic electronic memories are potentially a supplementary technology to the conventional memory technology facing challenges in miniaturizing from micro- to nano-scale. With an understanding of the current state of memory technology and the basic concepts of electronic memories, the historical development of polymer and organic electronic memories can be classified into three categories by drawing the mechanistic analog between the polymer/organic memory element and one of the three primary circuit elements, viz., capacitor, transistor and resistor [1]. A number of functionalized polyimides have been designed and synthesized to serve as electroactive materials in polymer resistive random access memories (PRAM). Their performances and operation mechanisms in dynamic random access memory (DRAM), static random access memory (SRAM), flash (re-writable) memory and write-once read-many-times (WORM) memory are discussed.

Reference

[1] Q.D. Ling, D.J. Liaw, C.X. Zhu, D.S.H. Chan, E.T. Kang and K.G. Neoh “Polymer Electronic Memories-Materials, Devices and Mechanisms”, Prog. Polym. Sci. 2008, 33: 917-978

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Jun Sakai and Yasuharu Yamada; Kyoto Institute of Technology, KIT Liaison Center, Department of Biomolecular Engineering, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JAPAN

Nanoporous Low-k Hyperbranched Polyimide

Nanoporous hyperbranched polyimide films were prepared and their physical, thermal, mechanical, and dielectric properties were investigated. Hyperbranched polyamic acids as precursors were prepared by polycondensation of a triamine monomer, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB), and dianhydride monomers, pyromellitic anhydride (PMDA), 4,4f-oxydiphthalic anhydride (ODPA), and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and subsequently modified the molecular end groups by 3-aminopropyltrimethoxysilane (APTrMOS). The nanoporous hyperbranched polyimide films were prepared by following steps. Hyperbranched polyimide-silica hybrid films were prepared by addition of tetramethoxysilane (TMOS) and water (sol-gel reaction) or addition of colloidal silica into hyperbranched polyamic acid solution and subsequently thermal imidizized at up to 300C. The hyperbranched polyimide-silica hybrid films were treated with hydrofluoric acid to remove the dispersed silica component to afford the porous polyimide films. The homogeneous dispersed nanopores (20-30nm) were formed in the hyperbranched polyimide films. The dielectric constant of nanoporous hyperbranched polyimide films decreased with increasing porosity (minimum 2.1 at 30vol% porosity) with high thermal stability (Td5 > 400C), mechanical strength, and transparency (>85% at 600nm). Therefore, nanoporous hyperbranched polyimide films were expected to use high-performance low-k material for microelectronics application.

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R. Khazaka ^1,2, S. Diaham^1,2, M. L. Locatelli^1,2 and B. Despax^1,2

1) Université de Toulouse; UPS, INPT; LAPLACE (Laboratoire Plasma et Conversion d'Energie); 118 route de Narbonne, F-31062 Toulouse cedex 9, FRANCE.

2) CNRS; LAPLACE; F-31062 Toulouse, FRANCE.

Oxidative Thermal Aging Effect on the Electrical Properties of BPDA/PDA Polyimide Films With and Without Oxygen Barrier Layers

The new wide band gap semiconductor materials, specially the most mature silicon carbide (SiC) one, allow the electronics operation at high temperatures from 200 to 400 ̊C against typically 200 ̊C at maximum for silicon devices. To benefit from the wide band gap semiconductor properties, suitable passivation materials are needed for high temperature applications. The BPDA/PDA polyimide (PI) appears as a good candidate for the passivation of SiC devices due to its high glass transition temperature (>350 ̊C), its CTE compatibility (3-6 ppm/̊C) with that of SiC (3-5 ppm/̊C) and its high dielectric strength (> 2 MV/cm). However polymides used at high temperature in presence of oxygen are subjected to thermo-oxidative reaction that can cause their electrical property degradation versus aging time. A mean to protect the PIs against the oxygen diffusion (or to slow down the latter that is activated with increasing temperature) in order to increase their long-term reliability could be to encapsulate them using oxygen barrier layers. The aim of the paper is to present and compare the BPDA/PDA electrical properties evolution versus time during thermal aging at 300̊C in air atmosphere of unprotected and protected films. The effect of unprotected film thickness, and the effect of the nature of the barrier layer (a plasma deposited inorganic coating and a thermally evaporated metallic coating) will be analyzed in order to discuss the oxygen barrier efficiency of the inorganic coating solution.

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Rakesh Kumar ; Specialty Coating Systems, 7645 Woodland Drive, Indianapolis, IN 46278

Parylene HT: a High Temperature Vapor Phase Polymer for Electronics Applications

A recent development in the area of high temperature polymers, which offers solutions to many existing packaging and reliability challenges of electronics industry, is described. Packaging, protection and reliability of various electronic devices and components that include PCB's, MEM's, optoelectronic devices, fuel cell components and nano-electronic parts are becoming more challenging due to their long-term performance requirements. Parylene HT offers solutions to many existing protective, packaging and reliability issues of electronic and medical industries in part because of its excellent electrical & mechanical properties, chemical inertness and long-term thermal stability at high temperature exposure to over 350^oC (short - term at 450 ^oC). Experimental results and trial runs demonstrate the ability of Parylene HT coating to meet the growing requirements of higher dielectric capabilities, higher temperature integrity and mechanical processing etc. of dynamic electronic industry. In addition, Parylene HT polymer coating truly conforms to the parts due to its molecular level deposition characteristics. Its suitability and biocompatibilty encourage researchers to explore Parylene HT’s role in sensors and in active electronic devices for various industries.

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Gennady Mikhailov; 13/1-161, Olga Forsh Street, 195269, St. Petersburg, RUSSIA

Interrelation Between Chemical Structure, Super-molecule Organization and Properties of the Polyarimide Fibers

 The role of structural fragments in the main chain of the fiber-forming polyarimides and the effect of the chemical and supramolecular structure on the properties of homo- and co-polyimide fibers were studied.

The main principles of the molecular engineering for obtaining the fibers with required mechanical properties have been proposed. Within the framework of the research the polyimide fibers with unique physical and mechanical properties have been obtained. Their elastic moduli achieved extra high values up to 280 GPa, tensile strength was up to 6 GPa and elongation at break could be varied from 2 to 10% if necessary.

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Masataka Murahara; Tokyo Institute of Technology, Innovation Propellant Department, Research Professor, and Professor Emeritus of Tokai University, Tokyo, JAPAN

 e-mail:murahara@vesta.ocn.ne.jp

Polymer Coating Surface Change into Ceramic Layer <Photo-oxidized Silicone Oil Layer for High Temperature and High Electric Insulation Resistance>

A film that is highly electrical insulating, water resistant, transparent, and hard as well is required as an insulator and a protector for a large-area solar panel in order to lighten its weight, for glass or plastic is conventionally used for the large-area solar panel. The silicone oil consists of siloxane bonds, and the chemical structure of quartz has siloxane bonds. The dimethylsiloxane silicone oil {[-O-Si(CH₂)-O-]n} coated on a sample surface is irradiated with the Xe₂ lamplight (172 nm) in the air, and the oxygen is excited by the UV-photon to generate a high active O atom. This active oxygen reacts with the silicone oil to generate (SiO₂)n, which will be a coating film or adhesive thin layer photo-oxidized. In result, the organic silicone oil turns to inorganic glass in the presence of oxygen. By this technique, an optical thin film can be made to transmit ultraviolet rays of wavelengths under 200 nm and enjoy the characteristics of homogeneity, high density, resistance to environment, resistance to water, anti-reflective in water, 5 in Mohs’ scale. The ultraviolet transmittance for 193 nm drastically rises from 53% of the untreated sample to 80 % in the first 30-minute irradiation and gradually increases to 83 % after 120-minute lamp irradiation. The Mohs’ scale also increases from 0 when untreated to 5 when irradiated for 90 minutes. Silicone oil (KF96-10) has a refractive index of 1.39 when untreated; which increases to 1.42 when irradiated for 60 minutes, and to 1.43 for 120 minutes.

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Brigitte Mutel ¹, Philippe Supiot¹, Adil Essakhi², Axel Löfberg², Sébastien Paul², Véronique Le Courtois² and Elisabeth Bordes-Richard².

1) Génie des Procédés d'Interactions Fluides Réactifs - Matériaux (GéPIFRéM), EA 3571, USTL, Villeneuve d’Ascq, FRANCE

2) Unité de Catalyse et de Chimie du Solide (UCCS), UMR 8181, USTL, Villeneuve d’Ascq, FRANCE

Coating of Structured Reactors by Plasma Assisted Polymerization of TMDSO

While organic compounds with polymerizable structure are required for conventional polymerization, any organic compound can be used in the frame of assisted plasma process. In particular, thin polysiloxane-like films can be obtained from polymerization of tetramethyldisiloxane (TMDSO) precursor, pre-mixed with oxygen, in a N₂ plasma remote afterglow. These films are very attractive because they show interesting mechanical, electrical, thermal and biocompatible properties.

In this paper, such a film is used to promote the bonding of a V₂O₅/TiO₂ catalyst on a metallic foam used as structured catalytic reactor. Such reactor would contribute to reduce the size of industrial chemical plant by increase of the chemical selectivity, and thus reducing risks and hazards. The aim of the work is to obtain a uniform layer avoiding poisoning of the active V₂O₅ phase by migration of iron from the substrate during catalytic reaction. The model reaction under consideration for the test is the oxidative dehydrogenation of propane to propene. Good results are obtained with the deposition of a 5 mm thick plasma polymer TMDSO layer followed by calcination at 650 ̊C during 1 hour in order to obtain a SiO₂ layer. TiO₂ was then dip-coated prior to anchoring of the active V₂O₅ phase in sol-gel medium. The originality of this work was to obtain a stable and homogeneous barrier layer in a 3D dimensions system like foam.

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Camille A. Thorpe, Feng Yang and Gordon Nelson; College of Science, Florida Institute of Technology, Melbourne, FL 32901, USA

Design, Synthesis and Characterization of Novel Ferrocene-Containing Polyimide Copolymers

Polyimides are typically used in microelectronic devices and space applications because they are thermally stable, chemically resistant, and have good mechanical and dielectric properties. It was previously observed that a copolymer of a diol-terminated ferrocene oligomer (FcOH) and a 4,4’- methyldiphenyl diisocyanate - based polyurethane (MDI-PU) exhibited FcOH blocks which preferentially localized toward the copolymer surface. This surface sequestration of the FcOH was essential for improved charge dissipation performance of the synthesized copolymers compared to unmodified MDI-PU and MDI-PU containing ferrocene as an additive. However, copolymers of FcOH and a polyimide based on 3,3’,4,4’-biphenyltetracarboxylic dianhydride /3,3’-oxydianiline (BO-PI) did not exhibit surface localization of FcOH.

In this work, novel copolymers of two amine-terminated ferrocene oligomers (FcNH₂) and BO-PI were synthesized, in addition to BO-PI containing the oligomers as additives. Surface levels of FcNH₂ in newly synthesized polymers were evaluated using Energy Dispersive X-ray Microanalysis (EDX) and attenuated total reflectance infrared spectroscopy (ATR-IR). Films were also evaluated using thermogravimetric analysis (TGA). It was observed that FcNH₂ did not localize to the surface of newly synthesized copolymers and polyimides containing oligomers as additives. Thus, newly synthesized polyimides are not candidates for further evaluation of electrostatic dissipation properties. Presence of FcNH₂ decreased thermal stability of BO-PI but improved char formation, indicating that newly synthesized polymers may be candidates for further evaluation of fire properties.

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Roy Odle; SABIC Innovative Plastics, 1 Lexan Lane, Mt. Vernon, IN 47620

E-mail: Roy.Odle@sabic-ip.com

Synthesis and Structure-Property Relationships of Polyetherimide-Sulfones

Ultem^® resin is a well-known and commercially established material in the high performance market place. This talk will discuss how different synthetic schemes are used to produce new amorphous polyimide resins containing sulfone moieties. Isomer variations as well as other structural modifications were integrated into a family of new commercial polymer systems. The resulting resins exhibited different and interesting property relationships that will be examined. Of special note is the observation that a 3,3’ isomer gives both higher Tg and improved melt flow over a similar 4,4’ isomer. These high Tg (245-300̊C) polymers can be easily melt processed on standard injection molding machines giving ready to use parts.

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Joung-Man Park ^1,4†, Zuo-Jia wang¹, Joel GnidaKouong¹, Ga-Young Gu¹,

Woo-Il Lee², Jong-Kyoo Park³ and K. Lawrence DeVries⁴

1) School of Materials Science and Engineering, Engineering Research Institute, Gyeongsang National University, Jinju 660-701, KOREA

2) School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 305-600, KOREA

3) Agency for Defense Development, 4-R&D Center, Deajeon 305-600, KOREA

4) Department of Mechanical Engineering, University of Utah,

Salt Lake City, Utah 84121, U. S. A.

E-mail: jmpark@gnu.ac.kr

Interfacial Aspects and Self-Sensing of Carbon Fiber/CNT-Phenol Nanocomposites using Electro-Micromechanical Techniques and Wettability

Interfacial evaluation and self-sensing were investigated for single carbon fiber reinforced phenol and carbon nanotube (CNT)-phenol nanocomposites by electro-micromechanical technique combined with wettability test. CNT-phenol nanocomposites were fabricated using optimum conditions by solvent dispersion under ultrasonication. The electrical properties of CNT-phenol nanocomposites were measured by two and four-point methods. Contact resistance of CNT-phenol nanocomposites was obtained using gradient specimen and electro-micropullout test under cyclic loading. There were consistent results between static and dynamic contact angles on neat phenol and CNT-phenol nanocomposites measured by optical and Wilhelmy plate methods. Since the hydrophobic domains of CNT are formed in heterogeneous style on the outermost surface, CNT-phenol nanocomposites exhibited hydrophobicity showing the advancing contact angle to be more than 90º. CNT-phenol nanocomposites exhibited a higher apparent modulus than neat phenol resin due to better stress transfer based on a good reinforcement in nanocomposites. Interfacial shear strength (IFSS) between single carbon fiber and CNT-phenol nanocomposites could be affected on not only the nanostructures of CNT at the interface but also apparent modulus of CNT-phenol nanocomposite.

†Acknowledgements: This work was supported by the Defense Acquisition Program Administration and ADD (UD070009AD), Korea. Wang, Zuo-Jia is grateful for fellowship support from the second stage of the BK21 program.

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Musto Pellegrino ¹, Mariangela Leo¹, Giuseppe Mensitieri² and Marino Lavorgna³

1) Institute of Chemistry and Technology of Polymers (ICTP), National Research Council of Italy, via Campi Flegrei, 34, Pozzuoli (Na), ITALY

2) Dept. of Materials and Production Engineering, University of Naples Federico II, P.le Tecchio 80, 80125 Naples, ITALY

3) Institute of Composite and Biomedical Materials, National Research Council of Italy P.le Tecchio 80, 80125 Naples, ITALY

Molecular Mechanism of Diffusion of H₂O and Methanol in PMDA-ODA Polyimide: a Time-resolved FTIR Study

Polyimides are a well known class of high-performance technopolymers characterized by outstanding properties in terms of thermal-oxidative stability, mechanical performances, high T_g and good resistance to solvents. These properties make them attractive for microelectronic and opto-electronic applications, and as membranes for separation technologies. In particular, the widespread application of polyimides in the membrane sector has stimulated numerous studies aimed at a deeper understanding of their peculiar transport properties. In this contribution the diffusion of water and methanol in a PMDA-ODA commercial polyimide is investigated in detail by in-situ, time-resolved FTIR spectroscopy using several methods of spectral data analysis, namely difference spectroscopy, least-squares curve fitting, 2D correlation spectroscopy and Normal Coordinate Analysis. These approaches provided relevant and complementary information about the transport process, in terms of overall diffusivity, molecular interactions and dynamics of the different molecular species present in the investigated systems. The results gave an insight into the molecular mechanism of diffusion in terms of number and population of penetrant species and with respect to the nature of the molecular aggregates. Finally, the comparison between the behaviour of the two different probes highlighted the relevance of the penetrant’s molecular structure (geometry, polarity, H-bonding capability) on the final transport properties of the systems.

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Javier Parrondo and B. Rambabu; Solid State Ionics and Surface Science Laboratory, Department of Physics, Southern University and A&M College, Baton Rouge, Louisiana 70813, USA

Email: rambabu@cox.net

Polybenzimidazole Membranes (PBI) for HT-PEMFCS: Synthesis, Fuel Cell Performance and Substantiate with That of Commercial High Temperature PEMS

Polybenzimidazole (PBI) membranes were prepared using polyphosphoric acid and employed as an electrode and electrolyte for HT-PEMFCs. The membranes containing 18 mol of phosphoric acid per mol of polymer repeating unit resulted in conductivities up to 0.1 S/cm in the range 120-200^oC, and exhibited good mechanical properties. They were tested and compared with the measurements of commercial membranes obtained from BASF and Advent Technologies. Analysis of polarization data of in house prepared membranes revealed that best performance for electrodes having 5 wt.% PBI at 180^oC. Cathode ionic resistance increased with temperature and within electrodes having lower concentrations of PBI. When PBI content was raised from 1 to 10 wt.%, ionic resistance (180 ^oC) decreased from 0.29 to 0.14 Ohm-cm², and further increase of PBI content has no effect. In the case of 5 wt.% electrodes, a 3-fold increase in the cathode resistance was observed when the temperature was raised from 140 to 180^oC. When PBI concentration increased from 5 to 30 wt.%, Warburg impedance increased 2.5 times reaching values as high as 6 Ohm-cm². The impedance data were in good agreement with the polarization curves, and optimum performance was obtained when overall resistance was minimal. In this paper we will present a detailed analysis showing the effect of PBI content on the transport properties and their influence on the performance up to 200 ⁰C.

This work is supported by U.S-DOD-ARO- W911NF-08-C-0415 and authors thank Dr. Robert Mantz and Dr. Thomas L. Reitz for supporting fuel cell research.

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Luke Roberson ¹, Shanju Zhang ², Chris Immer ³, Janusz Kowalik ² and Satish Kumar ²

1) NASA, Kennedy Space Center, FL

2) Georgia Institute of Technology, Polymer Textile and Fiber Engineering, Atlanta, GA

3) ASRC Aerospace, Kennedy Space Center, FL

Carbon Nanotube Fiber Filaments for Lighting Applications

This presentation will describe the manufacture techniques used to create wet and dry spun carbon nanotube fibers produced from mm-tall carbon nanotube forests synthesized by water assisted CVD. The mechanical properties of the fibers will be presented to examine the effects of twisting and fiber densification on mechanical performance. We will also discuss their electrical properties and possible application of these fibers as lighting filaments for terrestrial and space environments.

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A. L. Rusanov, L. G. Komarova, E. G. Bulycheva and M. G. Bugaenko; A. N. Nesmeyanov Iinstitute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Str., Moscow, 119991, RUSSIA

New Sulfonated Polyethers and Polynaphthylimides

New sulfonated aromatic polyethers and polynaphthylimides were prepared using 2,4,6-trinitrotoluene (TNT) derivatives as starting reagents. Aromatic polyethers were prepared by the interaction of 3,5-dinitrodiphenylsufone-4 -sulfonic acid with various bis-phenols under the conditions of aromatic nucleophilic nitrodisplacement reactions e.g. in dipolar aprotic solvents using K₂CO₃ as a base. Aromatic polynaphthylimides were prepared by the interaction of 3,5-diaminodiphenyl ether-4 -sulfonic acid with bis(naphthalic anhydrides) under the conditions of high-temperature solution polycyclocondensation reactions in phenolic solvents, using triethylamine and benzoic acid as catalyst. Alternative approach to the preparation of sulfonated polynaphthylimides included: 1) high-temperature solution polycyclocondensation of 3,5-diaminodiphenyl sulfide with bis(naphthalic anhydrides); 2) sulfonation of the polynaphthylimides thus obtained; 3) oxidation of sulfide “bridging” groups in the polynaphthylimides side chains.

All polyethers and polynaphthylimides thus obtained contain sulfonic acid groups in the side chains of their macromolecules.

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Francette Thominette; LIM ENSAM, 151 Bd de l’Hopital , 75013 Paris, FRANCE

Hygrothermal Aging of Nafion^®

For the development of Proton Exchange Membrane Fuel Cells (PEMFC), membrane durability is a crucial issue. Nafion® in-situ aging in fuel cell did not lead to determine a degradation mechanism. That is why ex-situ aging tests were performed, in drying oven and in climatic chambers, over 500 days on Nafion® 112 and on Nafion® 212-CS in practical fuel cell usage conditions (e.g. 80̊C, with a hygrometric rate between 0%RH and 95%RH). The evolution of the mechanical properties shows an increase of the Young modulus and a decrease of the breaking strain while the hydrophilicity (directly linked to the protonic conductivity) measured by DVS (Dynamic Vapour Sorption) decreases. The evolution of the polymer chemical structure, monitored by infrared spectroscopy, underlines sulfonic anhydride formation. An indirect proof of the anhydride formation is given by Nuclear Magnetic Resonance. The suggested mechanism is the sulfonic acid condensation to form an anhydride. The properties evolution is explained via this mechanism. The comparison of Nafion® 112 and Nafion® 212-CS shows that Nafion® 212-CS gets aged three times faster than Nafion® 112. The condensation reaction catalysis by metallic cations which concentrations is higher in Nafion® 112 explains the aging kinetics difference. Moreover, the tests done at different relative humidities show that when the hygrometric rate increases, the condensation reaction is accelerated. Lastly, we point out that, in presence of a catalyser, the condensation reaction is reversible: The anhydride is hydrolysed which leads to recovered properties. The membrane is rejuvenated.

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Narayanan Venkat ¹, Zongwu Bai¹, Thuy D. Dang^2*, Victor K. McNier¹, Jennifer N. DeCerbo³ and Jeffery T. Stricker³

1) University of Dayton Research Institute, 300 College Park Drive, Dayton OH 45469, USA

2) AFRL/RXBN, 2941 Hobson Way, Wright-Patterson Air Force Base, Dayton, OH 45433, USA

3) AFRL/RZPE, Power systems and Electrical Technology Branch, Wright-Patterson Air Force Base, Dayton, OH 45433, USA

Design of Polyimide and Other High Temperature Polymer Dielectrics for Aerospace Power Conditioning Capacitor Applications

High performance polymers such as polyimides and polybenzoxazoles have been known to possess an ideal suite of film thermo-mechanical properties for a variety of structural and electrical applications. There are extensive reports of the utilization of such polymers as interlayer dielectrics (ILDs) in micro-electronic packaging. However, as high temperature insulating dielectrics, they can also potentially address the stringent requirement of long-term wide-temperature electro-mechanical stability of power conditioning capacitor applications for aerospace. While the state-of-the-art power electronics systems typically use polycarbonate (PC) capacitors in wound capacitors for operation in the -55ºC to 125ºC range, current applications require high performance polymer films with dielectric stability in the range of 250-350ºC as upper limits for operation. In this context, variable temperature dielectric properties of metalized thin films derived from post-functionalized o-hydroxy polyimides as well as from fluorinated polybenzoxazoles with hydroxy pendants are described. Besides the above, the wide-temperature dielectric evaluation of an amorphous, high temperature fluorenyl polyester incorporating a diamond-like hydrocarbon unit it its backbone is also discussed. The focus of the investigation is on variable temperature dielectric measurements of film capacitance as well as its dissipation factor and the effect of thermal cycling on polymer dielectric stability.

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Rohitkumar H. Vora; Advanced Polymers Research & Technologies

8080, Heritage Drive, Alburtis, PA 18011 USA

e-mail: rohitvora@apr-technologies.com , and vora_rohit@yahoo.com

Designing of Next Generation of High Performance CeramImide^© Type Nanocomposite Materials for Aerospace and Defense Applications

Since last 20 years, high performance ‘Ceramer’ technology development is an ongoing research effort at various academic and industrial organizations. Earlier a project was undertaken for the development of high performance high-temperature stable ‘CeramImide^© nanocomposite materials’ technology based on fluoro-polyimide (6F-PI) polymer chemistry. As a part of this ongoing project, four series of high performance thermoplastic fluoro-poly(ether imide)s: [6FDA + m-SED], [6FDA + p-SED], [6FDA + BPADE], and [6FDA + o-BAPOB] (6F-PEI) polymers having their chemical compositions based on 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 4,4’-bis (3-aminophenoxy) diphenyl sulfone (m-SED), 4,4’-bis (4-aminophenoxy) diphenyl sulfone (p-SED), 2,2’-bis [4-(4-aminophenoxy) phenyl] propane (BPADE) and 1,2’-bis (4-aminophenoxy) benzene (o-BAPOB), and such diamine monomers treated organo-soluble MMT clay based CeramImide^© nanocomposite materials were successfully synthesized, characterized, developed and reported by Vora et al in last several years.

In this paper we report technology development of novel state-of-the-art 2-(3,4’-Carboxy anhydrophenyl-2(4-carboxyphenyl) hexafluoropropane (6F-TMA) and 2,2’-Bis (4-carboxyphenyl) hexafluoropropane (6F-DAc) monomers based two series of fluoro-poly(ether amide-imide) (6F-PEAI)/MMT clay nanocomposites, and fluoro-poly(ether amide) (6F-PEA)/MMT clay nanocomposite materials termed as ‘CeramImideAmide^©’ and ‘CeramiAmide^©’ nanocomposite materials, respectively. We carried out in-situ synthesis of these designed CeramImideAmide^© and CeramiAmide^©, fabrication and characterization of their films. XRD analysis showed varying amount of exfoliation of organo-soluble MMT clay at the molecular level in the 6F-PEAI and 6F-PEA matrix systems used. Nanocomposite films showed excellent improvement in certain critical properties, such as, chemical resistance, glass transition (T_g), CTE value, and mechanical properties as the organo-soluble MMT clay content increased. Their long-term thermo-oxidative stability (TOS) data and activation energy for thermal degradation kinetics calculated from TGA (Air) confirmed excellent thermal stability. These novel CeramImideAmide^© and CeramiAmide^© films also exhibited comparable water absorption relative to the CeramImide^© nanocomposites, and reduced water absorption relative to the control film samples of commercially available non-fluorinated poly(amide imide) Torlon^®, non-fluorinated poly(ether imide) ULTEM^®1000, and non-fluorinated polyimides Kapton^®H and Upilex^®S polyimides. The some analytical results will be discussed.

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Jason K. Ward, Mita Das and William J. Koros; School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA-30332, USA

EMAILS:

 jason.ward@chbe.gatech.edu, mita.das@chbe.gatech.edu, wjk@chbe.gatech.edu

Synthesis of 6FDA based Membranes for Olefin Paraffin Separations

Propylene is among the most important chemical feedstocks of the petrochemical industry. A significant amount of this olefin is found in petrochemical product streams. Membranes offer an attractive alternative to conventional cryogenic distillation approaches to purify propylene (C₃^’’) and propane (C₃). Much work has already been done with pure polymer, to increase the propylene permeability (P_C3”) and propylene/propane selectivity (P_C3”/ P_C3).

The primary focus of this research is to maintain high efficiency (selectivity) at higher pressures by suppressing plasticization.

We successfully synthesized 6FDA-6FpDA polyimide for propylene/propane separation. Our pure gas selectivity is 19 at 35ºC. Propylene induces plasticization at 35⁰C above 2 atm pressure with this polymer. We have been able to suppress the plasticization by performing the experiment at 70ºC and synthesizing very high molecular weight and narrow PI (polydispersity index) polymer.

One of the main challenges in thermal imidization we faced was the presence of insoluble white solid precipitate in the polymer solution. We have successfully eliminated this white precipitate and identified likely sources of the precipitate as a crosslinked oligomeric byproduct of the thermal imidization process. Our work compares thermal and chemical imidization with a goal of synthesizing high molecular weight and low PI (~2.0) polyimide to ensure the plasticization suppression.

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Luke Roberson, Craig Fortier¹, LaNetra Tate¹, Sarah Snyder², and Martha Williams¹

1) NASA, Kennedy Space Center, FL

2) ASRC Aerospace, Kennedy Space Center, FL

Carbon Nanotubes Printing Techniques for Enhanced Conductivity

Numerous technologies would benefit from an easily applied conductive layer onto a rigid or flexible substrate. In this presentation, we describe the synthesis of water-soluble inks containing single and multi-walled carbon nanotubes. These inks were printed directly onto a number of substrates, including transparency films, papers, and fabrics, using commercially available inkjet printers and cartridges. The formulations and production methods for this ink were optimized in order to increase printability, surface-ink interactions, and conductivity. Novel patterns were designed, printed, and analyzed for dust mitigation technologies for lunar surface applications.

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W.M. Shan Wickramanayake ¹ R.P. Lively, ¹ R. R. Chance, ¹ W. J. Koros, ¹ D.G. Peiffer, B. Carstensen and R. S. Polizzotti²

1) School of Chemical and Biomolecular Engineering , Georgia Institute of Technology, 311 Ferst Drive , Atlanta, GA 30332

2) ExxonMobil Research & Engineering, Corporate Strategic Research, Route 22 East, Annandale, NJ 08801

Hollow-Polyimide Spheres: Fabrication and Industrial Applications

Materials with pressure tunable densities and controllable diffusion properties have a wide range of applications from energy to pharmaceutical industry. In the current work, hollow, spherical, millimeter diameter scale polyimide ‘micro pillows’ (MPs) were fabricated via non-solvent induced phase separation/extraction, employing a dual layer spinneret extrusion system. MPs with wall thicknesses in the range of 45 - 350 μm were achieved via the extraction of the N-methyl-2-pyrrolidone (NMP) polymer solvent into a high molecular weight Poly(propylene glycol) (PPG) non-solvent. A small amount of heptane was introduced into the core of the particles during extrusion. Vaporization of that heptane at elevated temperatures avoided particle collapse during NMP solvent extraction. For the most dilute polymer solution feed, the final product was an imidized MPs with diameter of about 1.5 millimeters, a wall thickness of about 45 microns, and geometric compression ratio of 6. Specially, these MPs can potentially be used to control rheological properties of liquids. For example, during application, desired densities can be achieved by reversible collapse of MPs. Also, attractive mechanical and transport properties of these MPs make them an ideal storage media for slow releasing gases and liquids in energy and other industries.

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Yasuharu Yamada and Tomoyuki Suzuki, Kyoto Institute of Technology, KIT Liaison Center, Department of Biomolecular Engineering, Matsugasaki, Sakyo-ku, Kyoto 606-8585, JAPAN

E-mail: y-yamada@kit.ac.jp

Hyperbranched Polyimide-silica Hybrids for Gas Separation Membranes

Gas separation processes using polymeric membranes have greatly been developed during the last three decades. Especially polyimides have been of great interest in gas separation membranes because of their high gas selectivity and excellent thermal and mechanical properties. Organic - inorganic hybrids are also attractive materials since they generally possess desirable organic and inorganic properties. Hybridization with inorganic compounds has been focused on the modification of polyimides in order to improve their thermal, mechanical, and gas transport properties. Recently, we developed novel hyperbranched polyimide-silica hybrid (HBPI-SiO2 HBD) membranes prepared by polycondensation of a triamine, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB), and various dianhydrides followed by hybridization with tetramethoxysilanes (TMOS) and methyltrimethoxysilane (MTMS), and investigated their physical and gas transport properties. As a result, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)-TAPOB HBPI exhibits high gas permeability and selectivity with high thermal and mechanical properties arising from the characteristic hyperbranched structure and the incorporation of silica component. Especially, CO2 permeability and CO2/CH4 permselectivity of 6FDA-TAPOB HBPI membranes significantly increase with increasing silica content, suggesting characteristic distribution and interconnectivity of free volume holes created by the incorporation of silica, which are expected to apply to high-performance CO2/CH4 separation membranes. In this presentation, the preparation, physical and gas transport properties of HBPI-SiO2 HBD membranes are discussed.

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Revised -- 10/15/2009
URL: http://mstconf.com/polyimd6-abs.htm