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Sample records for crystalline polymer lcp

  1. Liquid Crystal Polymer (LCP) based antenna for flexible system on package (SoP) applications

    KAUST Repository

    Marnat, Loic; Shamim, Atif

    2012-01-01

    The design, fabrication and measurement of a bowtie antenna on a flexible Liquid Crystal Polymer (LCP) substrate is reported in this paper. The antenna is fed by a balun transition which helps improve the gain up to 5.1 dB. The antenna performance is analyzed for both planar and curved substrates. The comparison between simulation and measurements shows a good agreement. This structure can either be used to sense the bending of the substrate or use the bending to tilt the beam. © 2012 IEEE.

  2. Liquid Crystal Polymer (LCP) based antenna for flexible system on package (SoP) applications

    KAUST Repository

    Marnat, Loic

    2012-06-01

    The design, fabrication and measurement of a bowtie antenna on a flexible Liquid Crystal Polymer (LCP) substrate is reported in this paper. The antenna is fed by a balun transition which helps improve the gain up to 5.1 dB. The antenna performance is analyzed for both planar and curved substrates. The comparison between simulation and measurements shows a good agreement. This structure can either be used to sense the bending of the substrate or use the bending to tilt the beam. © 2012 IEEE.

  3. Effect of organoclay on the orientation and thermal properties of liquid-crystalline polymers

    CSIR Research Space (South Africa)

    Bandyopadhyay, J

    2007-08-01

    Full Text Available in the pure LCP; in the nanocomposites, the polymer chains tended to orient in the direction of the dispersed clay layers. According to the DSC results, during first heating, the first melting peak represents the crystalline to nematic transition and, after...

  4. Liquid crystalline order in polymers

    CERN Document Server

    Blumstein, Alexandre

    1978-01-01

    Liquid Crystalline Order in Polymers examines the topic of liquid crystalline order in systems containing rigid synthetic macromolecular chains. Each chapter of the book provides a review of one important area of the field. Chapter 1 discusses scattering in polymer systems with liquid crystalline order. It also introduces the field of liquid crystals. Chapter 2 treats the origin of liquid crystalline order in macromolecules by describing the in-depth study of conformation of such macromolecules in their unassociated state. The chapters that follow describe successively the liquid crystalli

  5. The effect of glassfibre, graphite and MoS2 on the tribological performance of a liquid crystalline polymer

    NARCIS (Netherlands)

    Dufour, P.R.; de Gee, A.W.J.; Kingma, J.A.; Mens, J.W.M.

    1992-01-01

    A thermotropic liquid crystalline polymer (LCP) with a high melting point of approximately 400 °C, unfilled and filled with glassfibre, MoS2 or graphitic carbon was tested in dry sliding contact with steel. Three different test methods were applied, i.e. measurement of coefficient of friction and

  6. Irradiation sterilization of semi-crystalline polymers

    International Nuclear Information System (INIS)

    Williams, J.; Dunn, T.; Stannett, V.

    1978-01-01

    A semi-crystalline polymer such as polypropylene, is sterilized by high energy irradiation, with the polymer containing a non-crystalline mobilizing additive which increases the free volume of the polymer, to prevent embrittlement of the polymer during and subsequent to the irradiation. The additive has a density of from 0.6 to 1.9 g/cm 3 and a molecular weight from 100 to 10,000 g/mole

  7. Liquid crystalline polymer nanocomposites reinforced with in-situ reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    D. Pedrazzoli

    2015-08-01

    Full Text Available In this work liquid-crystalline polymer (LCP nanocomposites reinforced with in-situ reduced graphene oxide are investigated. Graphene oxide (GO was first synthesized by the Hummers method, and the kinetics of its thermal reduction was assessed. GO layers were then homogeneously dispersed in a thermotropic liquid crystalline polymer matrix (Vectran®, and an in-situ thermal reduction of GO into reduced graphene oxide (rGO was performed. Even at low rGO amount, the resulting nanocomposites exhibited an enhancement of both the mechanical properties and the thermal stability. Improvements of the creep stability and of the thermo-mechanical behavior were also observed upon nanofiller incorporation. Furthermore, in-situ thermal reduction of the insulating GO into the more electrically conductive rGO led to an important surface resistivity decrease in the nanofilled samples.

  8. Polymer and Polymer Gel of Liquid Crystalline Semiconductors

    Institute of Scientific and Technical Information of China (English)

    Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

    2004-01-01

    It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

  9. Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)

    Czech Academy of Sciences Publication Activity Database

    Meille, S. V.; Allegra, G.; Geil, P. H.; He, J.; Hess, M.; Jin, J.-I.; Kratochvíl, Pavel; Mormann, W.; Stepto, R.

    2011-01-01

    Roč. 83, č. 10 (2011), s. 1831-1871 ISSN 0033-4545 Institutional research plan: CEZ:AV0Z40500505 Keywords : IUPAC Polymer Division * crystalline polymers * crystalline polymer conformation Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.789, year: 2011

  10. Temperature influence in crystallinity of polymer microspheres

    International Nuclear Information System (INIS)

    Rezende, Cristiane de P.; Novack, Katia M.

    2011-01-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  11. CFRP materials reinforced with LCP fibres for applications in vehicle and aircraft engineering. Final report; Faserverbundkunststoffe mit einer LCP-Faserverstaerkung fuer Anwendungen im Fahrzeug- und Flugzeugbau. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-11

    CFRP materials reinforced with liquid crystalline polyester (LCP) fibres were produced and characterized with regard to their physical and mechanical characteristics. Compared with non-reinforced plastics, polypropylene/LCP fibre-UD laminates produced by filmstacking, epoxy resin/LCP fibre-UD laminates produced by spooling and epoxy resin composites with internal LCP fibre fleece had significantly higher strength and stiffness as well as high thermoforming resistance and waterproofness. [Deutsch] In diesem Forschungsvorhaben wurden Faserverbundkunststoffe mit einer Verstaerkungsfaser auf Basis eines thermotropen fluessigkristallinen Polyester [Liquid Crystalline Polyester, abgekuerzt LCP] hergestellt und bezueglich der physikalisch-mechanischen Eigenschaften charakterisiert. Die im `filmstacking`-Verfahren hergestellte Polypropylen/LCP-Faser-UD-Laminate und mittels Bewicklung gewonnene Epoxidharz/LCP-Faser-UD-Laminate sowie Epoxidharzverbunde mit eingearbeiteten LCP-Faservlies zeigen gegenueber den unverstaerkten Kunststoffmaterialien einen betraechtlichen Anstieg von Festigkeit und Steifigkeit. Die Faserverbunde weisen ausserdem eine hohe Waermeformbestaendigkeit und Wassersperrwirkung auf. (orig.)

  12. Pengaruh Kecepatan Pendinginan Terhadap Perubahan Volume Leburan Polymer Crystalline dan Non-Crystalline

    OpenAIRE

    Fahrurrozi, Mohammad; Moristanto, Bagus Senowulung dan

    2003-01-01

    AbstractThe study was directed to develop a method to predict the influence of the rate of cooling to the degree of crystallittitv (DOC) and volume change of crystalline polymers. Crystalline polymer melts exhibit volume shrinkage on cooling below melting point due to crystallization. Crystallization and volunrc shrinkage will proceed with varies rate as long as the temperature is above the glass tansition temperatrre. DOC achieved by polymer is not only determined by the inherent crystallini...

  13. Liquid crystalline thermosetting polymers as protective coatings for aerospace

    NARCIS (Netherlands)

    Guerriero, G.L.

    2012-01-01

    Environmental regulations are driving the development of new aerospace coating systems, mainly to eliminate chromates and reduce volatile organic compound (VOC) emissions. Among the various potential options for new coating materials, liquid crystalline polymers (LCPs) are attractive due to their

  14. Effect of expanded graphite and PEI-co-Silicon Rubber on the thermo mechanical, morphological as well as rheological properties of in situ composites based on poly (ether imide) and liquid crystalline polymer

    Energy Technology Data Exchange (ETDEWEB)

    Hatui, Goutam, E-mail: hatui.goutam@gmail.com; Malas, Asish, E-mail: malasasish@gmail.com; Bhattacharya, Pallab; Dhibar, Saptarshi, E-mail: saptaaus2007@gmail.com; Kundu, Mrinal Kanti, E-mail: kanti.mrinal19@gmail.com; Kumar Das, Chapal, E-mail: chapal12@yahoo.co.in

    2015-01-15

    Highlights: • PEI/LCP/ PEI-co-Silicon Rubber/EG and PEI/LCP/MWCNT nano composites are prepared by melt blending method. • The dispersions of acid modified expanded graphite were improved in presence of PEI-co-Silicon Rubber. • Thermal stability was found to be highest for PLGC composite. • Storage modulus and Young’s modulus showed an upward trend with incorporation of only EG and EG in presence of PEI-co-Silicon Rubber. • Among the nano composites PLGC has highest viscosity. - Abstract: Nanocomposites of polyether imide (PEI) and liquid crystalline polymer (LCP) with either MWCNT, Expanded Graphite (EG) or in combination of both EG and PEI-co-Silicon Rubber were prepared by melt blending process. The compatibility between the polymeric phases (PEI and LCP) was observed to be increased by the addition of PEI-co-Silicon Rubber while the only MWCNT added system (PLC) resulted in smaller LCP droplets. A continuous morphology was produced in presence of both PEI-co-Silicon Rubber and EG both added system (PLGR). This was due to the compatibilizing effect of PEI-co-Silicon Rubber. FTIR analysis revealed interaction between PEI and LCP in presence of PEI-co-Silicon Rubber. Remarkable increment of storage modulus was observed with the addition of EG and PEI-co-Silicon Rubber. Transmission Electron Microscope (TEM) analysis showed better dispersion of multiple graphene layers of EG in presence of PEI-co-Silicon Rubber compatibilized system. Tensile and Young’s modulus both were highest for EG/ PEI-co-Silicon Rubber added system. This is due to flexible compatibilizing effect of PEI-co-Silicon Rubber which delayed the detachment of LCP domain from the PEI matrix and thus detains the fracture.

  15. Effect of expanded graphite and PEI-co-Silicon Rubber on the thermo mechanical, morphological as well as rheological properties of in situ composites based on poly (ether imide) and liquid crystalline polymer

    International Nuclear Information System (INIS)

    Hatui, Goutam; Malas, Asish; Bhattacharya, Pallab; Dhibar, Saptarshi; Kundu, Mrinal Kanti; Kumar Das, Chapal

    2015-01-01

    Highlights: • PEI/LCP/ PEI-co-Silicon Rubber/EG and PEI/LCP/MWCNT nano composites are prepared by melt blending method. • The dispersions of acid modified expanded graphite were improved in presence of PEI-co-Silicon Rubber. • Thermal stability was found to be highest for PLGC composite. • Storage modulus and Young’s modulus showed an upward trend with incorporation of only EG and EG in presence of PEI-co-Silicon Rubber. • Among the nano composites PLGC has highest viscosity. - Abstract: Nanocomposites of polyether imide (PEI) and liquid crystalline polymer (LCP) with either MWCNT, Expanded Graphite (EG) or in combination of both EG and PEI-co-Silicon Rubber were prepared by melt blending process. The compatibility between the polymeric phases (PEI and LCP) was observed to be increased by the addition of PEI-co-Silicon Rubber while the only MWCNT added system (PLC) resulted in smaller LCP droplets. A continuous morphology was produced in presence of both PEI-co-Silicon Rubber and EG both added system (PLGR). This was due to the compatibilizing effect of PEI-co-Silicon Rubber. FTIR analysis revealed interaction between PEI and LCP in presence of PEI-co-Silicon Rubber. Remarkable increment of storage modulus was observed with the addition of EG and PEI-co-Silicon Rubber. Transmission Electron Microscope (TEM) analysis showed better dispersion of multiple graphene layers of EG in presence of PEI-co-Silicon Rubber compatibilized system. Tensile and Young’s modulus both were highest for EG/ PEI-co-Silicon Rubber added system. This is due to flexible compatibilizing effect of PEI-co-Silicon Rubber which delayed the detachment of LCP domain from the PEI matrix and thus detains the fracture

  16. Electric properties of a liquid crystalline methacrylic polymer

    International Nuclear Information System (INIS)

    Gonzalez Henriquez, C.M.; Soto Bustamante, E.A.; Haase, W.

    2009-01-01

    The formation of a liquid crystalline polymer called PM6R8 is reported. The polymers were obtained with different concentration of AIBN as initiator (0.25, 0.50, 1 and 2mg in 5ml solution) and time of reaction (24, 36 and 48 hours). The compounds were characterized by 1 H-NMR, differential thermal analysis (DTA), X-ray diffractometer and pyroelectric measurements. For the polymer a smectic C 2 phase occurs over broad temperature range, which is a possible explanation for the electric signal. The arrangement of the molecules within of the crystalline lattice is related with the kinetic of precipitation. (author)

  17. Integrated microsystems packaging approach with LCP

    Science.gov (United States)

    Jaynes, Paul; Shacklette, Lawrence W.

    2006-05-01

    Within the government communication market there is an increasing push to further miniaturize systems with the use of chip-scale packages, flip-chip bonding, and other advances over traditional packaging techniques. Harris' approach to miniaturization includes these traditional packaging advances, but goes beyond this level of miniaturization by combining the functional and structural elements of a system, thus creating a Multi-Functional Structural Circuit (MFSC). An emerging high-frequency, near hermetic, thermoplastic electronic substrate material, Liquid Crystal Polymer (LCP), is the material that will enable the combination of the electronic circuit and the physical structure of the system. The first embodiment of this vision for Harris is the development of a battlefield acoustic sensor module. This paper will introduce LCP and its advantages for MFSC, present an example of the work that Harris has performed, and speak to LCP MFSCs' potential benefits to miniature communications modules and sensor platforms.

  18. Liquid crystalline thermosetting polymers as protective coatings for aerospace

    OpenAIRE

    Guerriero, G.L.

    2012-01-01

    Environmental regulations are driving the development of new aerospace coating systems, mainly to eliminate chromates and reduce volatile organic compound (VOC) emissions. Among the various potential options for new coating materials, liquid crystalline polymers (LCPs) are attractive due to their unique combination of mechanical properties and chemical resistance. Their use, however, has been limited mainly due to poor adhesion properties. Thermotropic liquid crystalline thermosets displayed ...

  19. Thermal degradation of polymer systems having liquid crystalline oligoester segment

    Directory of Open Access Journals (Sweden)

    Renato Matroniani

    Full Text Available Abstract Block copolymers and blends comprised by liquid crystalline oligoester and polystyrene were prepared and their thermal stability were characterized by thermogravimetric analysis (TGA. The samples have shown three main decomposition temperatures due to (1 lost of flexible chain and decomposition of mesogenic segment, (2 decomposition of polystyrene and (3 final decomposition of oligoester rigid segment. Both copolymers and polymer blends presented lower thermal stability compared to polystyrene and oligoester. The residual mass after heating at 600 °C in copolymers and polymer blends were lower than those found in the oligoesters. A degradative process of aromatic segments of oligoester induced by decomposition of polystyrene is suggested.

  20. Damage characterization for particles filled semi-crystalline polymer

    Directory of Open Access Journals (Sweden)

    Lauro Franck

    2015-01-01

    Full Text Available Damage evolution and characterization in semi-crystalline polymer filled with particles under various loadings is still a challenge. A specific damage characterization method using Digital Image Correlation is proposed for a wide range of strain rates considering tensile tests with hydraulic jacks as well as Hopkinson's bars. This damage measurement is obtained by using and adapting the SEE method [1] which was developed to characterize the behaviour laws at constant strain rates of polymeric materials in dynamic. To validate the characterization process, various damage measurement techniques are used under quasi-static conditions before to apply the procedure in dynamic. So, the well-known damage characterization by loss of stiffness technique under quasi-static loading is applied to a polypropylene. In addition, an in-situ tensile test, carried out in a microtomograph, is used to observe the cavitation phenomenon in real time. A good correlation is obtained between all these techniques and consequently the proposed technique is supposed suitable for measuring the ductile damage observed in semi-crystalline polymers under dynamic loading. By applying it to the semi-crystalline polymer at moderate and high speed loadings, the damage evolution is measured and it is observed that the damage evolution is not strain rate dependent but the failure strain on the contrary is strain rate dependent.

  1. Transient molecular orientation and rheology in flow aligning thermotropic liquid crystalline polymers

    International Nuclear Information System (INIS)

    Ugaz, Victor M.; Burghardt, Wesley R.; Zhou, Weijun; Kornfield, Julia A.

    2001-01-01

    Quantitative measurements of molecular orientation and rheology are reported for various transient shear flows of a nematic semiflexible copolyether. Unlike the case of lyotropic liquid crystalline polymers (LCPs), whose structure and rheology in shear are dominated by director tumbling, this material exhibits flow aligning behavior. The observed behavior is quite similar to that seen in a copolyester that we have recently studied [Ugaz and Burghardt (1998)], suggesting that flow aligning dynamics may predominate in main-chain thermotropes that incorporate significant chain flexibility. Since the flow aligning regime has received little attention in previous attempts to model the rheology of textured, polydomain LCPs, we attempt to determine whether available models are capable of predicting the orientation and stress response of this class of LCP. We first examine the predictions of the polydomain Ericksen model, an adaptation of Ericksen's transversely isotropic fluid model which accounts for the polydomain distribution of director orientation while neglecting distortional elasticity. This simple model captures a number of qualitative and quantitative features associated with the evolution of orientation and stress during shear flow inception, but cannot cope with reversing flows. To consider the possible role of distortional elasticity in the re-orientation dynamics upon reversal, we evaluate the mesoscopically averaged domain theory of Larson and Doi [Larson and Doi (1991)], which incorporates a phenomenological description of distortional elastic effects. To date, their approach to account for polydomain structure has only been applied to describe tumbling LCPs. We find that it captures the qualitative transient orientation response to flow reversals, but is less successful in describing the evolution of stresses. This is linked to the decoupling approximation adopted during the model's development. Finally, a modified polydomain Ericksen model is introduced

  2. Liquid crystallinity in flexible and rigid rod polymers

    International Nuclear Information System (INIS)

    Pickett, Galen T.; Schweizer, Kenneth S.

    2000-01-01

    We apply an anisotropic version of the polymer reference interaction site model (PRISM) integral equation description of flexible polymers to analyze athermal liquid crystallinity. The polymers are characterized by a statistical segment length, σ o , and by a physical hard-core thickness, d, that prevents the overlap of monomers on different chains. At small segment densities, ρ, the microscopic length scale d is irrelevant (as it must be in the universal semidilute regime), but becomes important in concentrated solutions and melts. Under the influence of the excluded volume interactions alone, the chains undergo a lyotropic, first-order isotropic-nematic transition at a concentration dependent upon the dimensionless ''aspect ratio,'' σ o /d. The transition becomes weaker as d→0, becoming second order, as has been previously shown. We extend the theory to describe the transition of rigid, thin rods, and discuss the evolution of the anisotropic liquid structure in the ordered phase. (c) 2000 American Institute of Physics

  3. High Q, Miniaturized LCP-Based Passive Components

    KAUST Repository

    Shamim, Atif

    2014-10-16

    Various methods and systems are provided for high Q, miniaturized LCP-based passive components. In one embodiment, among others, a spiral inductor includes a center connection and a plurality of inductors formed on a liquid crystal polymer (LCP) layer, the plurality of inductors concentrically spiraling out from the center connection. In another embodiment, a vertically intertwined inductor includes first and second inductors including a first section disposed on a side of the LCP layer forming a fraction of a turn and a second section disposed on another side of the LCP layer. At least a portion of the first section of the first inductor is substantially aligned with at least a portion of the second section of the second inductor and at least a portion of the first section of the second inductor is substantially aligned with at least a portion of the second section of the first inductor.

  4. High Q, Miniaturized LCP-Based Passive Components

    KAUST Repository

    Shamim, Atif; Arabi, Eyad A.

    2014-01-01

    Various methods and systems are provided for high Q, miniaturized LCP-based passive components. In one embodiment, among others, a spiral inductor includes a center connection and a plurality of inductors formed on a liquid crystal polymer (LCP) layer, the plurality of inductors concentrically spiraling out from the center connection. In another embodiment, a vertically intertwined inductor includes first and second inductors including a first section disposed on a side of the LCP layer forming a fraction of a turn and a second section disposed on another side of the LCP layer. At least a portion of the first section of the first inductor is substantially aligned with at least a portion of the second section of the second inductor and at least a portion of the first section of the second inductor is substantially aligned with at least a portion of the second section of the first inductor.

  5. Crystalline morphology of the matrix of PEEK-carbon fiber aromatic polymer composites. I. Assessment of crystallinity

    International Nuclear Information System (INIS)

    Blundell, D.J.; Chalmers, J.M.; Mackenzie, M.W.; Gaskin, W.F.

    1985-01-01

    The crystallinity of the polyetheretherketone (PEEK) matrix polymer in the Aromatic Polymer Composite APC-2 has been estimated using a combination of techniques based on wide angle x-ray diffraction and infrared reflection spectroscopy. Crystallinity varies systematically with cooling rate and annealing time over the range 20 to 40%. The occurrence of oriented crystal growth of the PEEK relative to the carbon fiber can be monitored by x-ray diffraction. 8 references, 10 figures, 1 table

  6. Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

    KAUST Repository

    Heumueller, Thomas

    2014-08-01

    In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which polymer is used. We show that the light-induced traps are in the bulk of the active layer and we find a direct correlation between their presence and the open-circuit voltage loss in devices made with amorphous polymers. Solar cells made with crystalline polymers do not show characteristic open circuit voltage losses, even though light-induced traps are also present in these devices. This indicates that crystalline materials are more resistant against the influence of traps on device performance. Recent work on crystalline materials has shown there is an energetic driving force for charge carriers to leave amorphous, mixed regions of bulk heterojunctions, and charges are dominantly transported in pure, ordered phases. This energetic landscape allows efficient charge generation as well as extraction and also may benefit the stability against light-induced traps. This journal is © the Partner Organisations 2014.

  7. New theories for smectic and nematic liquid crystalline polymers

    International Nuclear Information System (INIS)

    Dowell, F.

    1987-01-01

    A summary of results from new statistical-physics theories for both backbone and side-chain liquid crystalline polymers (LCPs) and for mixtures with LCPs is presented. Thermodynamic and molecular ordering properties (including odd-even effects) have been calculated as a function of pressure, density, temperature, and molecule chemical structures (including degree of polymerization and the following properties of the chemical structures of the repeat units: lengths and shapes, intra-chain rotation energies, dipole moments, site-site polarizabilities and Lennard-Jones potentials, etc.) in nematic and multiple smectic-A LC phases and in the isotropic liquid phase. These theories can also be applied to combined LCPs. Since these theories have no ad hoc or arbitrarily adjustable parameters, these theories have been used to design new LCPs and new solvents and to predict and explain properties

  8. Autophobicity and layering behavior of thin liquid-crystalline polymer films.

    NARCIS (Netherlands)

    Wielen, van der M.W.J.; Cohen Stuart, M.A.; Fleer, G.J.

    1998-01-01

    The stability against breaking-up of thin spin-coated films of liquid-crystalline polymers depends on the film thickness and annealing temperature. This study concerns side-chain liquid-crystalline polymers, based on alternating copolymers of maleic anhydride and mesogenic alkenes. The mesogenic

  9. Effect of Ultrasonic Vibration on Mechanical Properties of 3D Printing Non-Crystalline and Semi-Crystalline Polymers.

    Science.gov (United States)

    Li, Guiwei; Zhao, Ji; Wu, Wenzheng; Jiang, Jili; Wang, Bofan; Jiang, Hao; Fuh, Jerry Ying Hsi

    2018-05-17

    Fused deposition modeling 3D printing has become the most widely used additive manufacturing technology because of its low manufacturing cost and simple manufacturing process. However, the mechanical properties of the 3D printing parts are not satisfactory. Certain pressure and ultrasonic vibration were applied to 3D printed samples to study the effect on the mechanical properties of 3D printed non-crystalline and semi-crystalline polymers. The tensile strength of the semi-crystalline polymer polylactic acid was increased by 22.83% and the bending strength was increased by 49.05%, which were almost twice the percentage increase in the tensile strength and five times the percentage increase in the bending strength of the non-crystalline polymer acrylonitrile butadiene styrene with ultrasonic strengthening. The dynamic mechanical properties of the non-crystalline and semi-crystalline polymers were both improved after ultrasonic enhancement. Employing ultrasonic energy can significantly improve the mechanical properties of samples without modifying the 3D printed material or adjusting the forming process parameters.

  10. Confined crystallization, crystalline phase deformation and their effects on the properties of crystalline polymers

    Science.gov (United States)

    Wang, Haopeng

    With the recent advances in processing and catalyst technology, novel morphologies have been created in crystalline polymers and they are expected to substantially impact the properties. To reveal the structure-property relationships of some of these novel polymeric systems becomes the primary focus of this work. In the first part, using an innovative layer-multiplying coextrusion process to obtain assemblies with thousands of polymer nanolayers, dominating "in-plane" lamellar crystals were created when the confined poly(ethylene oxide) (PEO) layers were made progressively thinner. When the thickness was confined to 25 nanometers, the PEO crystallized as single, high-aspect-ratio lamellae that resembled single crystals. This crystallization habit imparted more than two orders of magnitude reduction in the gas permeability. The dramatic decrease in gas permeability was attributed to the reduced diffusion coefficient, because of the increase in gas diffusion path length through the in-plane lamellae. The temperature dependence of lamellar orientation and the crystallization kinetics in the confined nanolayers were also investigated. The novel olefinic block copolymer (OBC) studied in the second part consisted of long crystallizable sequences with low comonomer content alternating with rubbery amorphous blocks with high comonomer content. The crystallizable blocks formed lamellae that organized into space-filling spherulites even when the fraction of crystallizable block was so low that the crystallinity was only 7%. These unusual spherulites were highly elastic and recovered from strains as high as 300%. These "elastic spherulites" imparted higher strain recovery and temperature resistance than the conventional random copolymers that depend on isolated, fringed micellar-like crystals to provide the junctions for the elastomeric network. In the third part, positron annihilation lifetime spectroscopy (PALS) was used to obtain the temperature dependence of the free

  11. Fiscal 1998 achievement report on regional consortium research and development project. Venture business fostering regional consortium in its 2nd year--Creation of key industries (Development of processing of new structure-designed high-performance polymer alloy); 1998 nendo shinkina kozo seigyo koseino kobunshi alloy no seikei kako ni kansuru kenkyu kaihatsu seika hokokusho. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Efforts are exerted to make novel recyclable polymer alloys excellent in material characteristic and to develop a technology for processing them, for which liquid crystalline polymers equipped with a self-alignment capability are combined with thermoplastic resins. In the research on the alloying of polyethylene terephthalate (PET) and liquid crystal polymers (LCP), studies are conducted about inorganic nucleating additives, thermostabilizers, and mold releasing lubricants, and a success is attained in the manufacture of excellent alloyed pellets. In the injection molding of alloys of PET and LCP, a product is obtained, among those produced with the rate of LCP varied, which behaves excellently even at a high resin temperature of 285 degrees C. It is found about PET/LCP alloys that improvement is achieved with additional LCP in terms of the warpage temperature under load, bending property, strength, and dimensional stability upon exposure to heat. In the study of the response of LCP-diffused PET to a process demanding distortion, an injection-molded product containing 10-20% of LCP is found to exhibit excellent ductility. It is also found that PET/LCP alloys may be cut and machined easily and that therefore their crushing for the recycling purpose will be easy. (NEDO)

  12. Interest of neutron scattering for the investigation of liquid-crystalline polymers

    International Nuclear Information System (INIS)

    Noirez, L.

    1994-01-01

    Small-angle Neutron scattering is the unique method which allows the determination of polymer conformation in the bulk state. This method has been applied to several kinds of liquid crystalline polymers. Results concerning side-chain liquid-crystal polymer, main-chain liquid-crystal polymer and combined liquid-crystal polymers, are reported. It is shown that the polymer conformation is largely dependent on the insertion site of the liquid crystal molecule and of the structure of the meso-phase. (author). 11 refs

  13. Sensing of environmental pollutant by conductive composite from prepared from hyperbranched polymer-grafted carbon black and crystalline polymer

    International Nuclear Information System (INIS)

    Taniguchi, Y.; Chen, J.; Ogawa, M.; Yokoyama, K.; Shimizu, H.; Tsubokawa, N.; Maekawa, Y.; Yoshida, M.

    2002-01-01

    Complete text of publication follows. The hyperbranched (HB) polymer-grafted (PG) carbon blacks (CB) have the possibility of utilizing as a support of catalyst and enzyme, and a curing agent of epoxy resin, because they have much terminal amino or hydroxyl groups. The postgrafting of crystalline polymer onto HB PG CB and the sensing of environmental pollutant by the conductive composite prepared from the polymer-postgrafted CB was discussed. The grafting of poly(amidoamide) onto CB surface was achieved by repeating either Michael addition of methyl acrylate to amino group on the surface or the amidation of the resulting terminal methyl ester group with ethylene diamine. HB polyester onto CB surface was grafted by stepwise growth of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) from surface carboxyl and hydroxyl groups on CB as a core in the presence of p-toluenesulfonic acid (p-TSA). The one-pot grafting of HB polyester onto CB as core was also achieved by the polycondensation of bis-MPA in the presence of p-TSA. Postgrafting of crystalline polymer onto HB polymer-grafted CB was achieved by the reaction of terminal amino or hydroxyl groups of grafted chain with COCl-terminated crystalline polymer. The electric resistance of the composite prepared from crystalline polymer-postgrafted CB was found to increase drastically in hexane, containing environmental pollutant, such as chloroform and trichloroethane, and returned immediately to the initial resistance when it was transferred into pure hexane. Based on the above results, it is concluded that the composite can be used as a novel sensor for environmental pollutant in solution

  14. Cross-Linked Liquid Crystalline Systems From Rigid Polymer Networks to Elastomers

    CERN Document Server

    Broer, Dirk

    2011-01-01

    With rapidly expanding interest in liquid crystalline polymers and elastomers among the liquid crystal community, researchers are currently exploring the wide range of possible application areas for these unique materials, including optical elements on displays, tunable lasers, strain gauges, micro-structures, and artificial muscles. Written by respected scientists from academia and industry around the world, who are not only active in the field but also well-known in more traditional areas of research, "Cross-Linked Liquid Crystalline Systems: From Rigid Polymer Networks to Elastomers&qu

  15. Electro-optics of novel polymer-liquid crystalline composites

    International Nuclear Information System (INIS)

    Ibragimov, T.D.; Bayramov, G.M.; Imamaliyev, A.R.; Bayramov, G.M.

    2014-01-01

    The polymer network liquid crystals based on the liquid crystals H37 and 5CB with PMVP and PEG have been developed. Mesogene substance HOBA is served for stabilization of obtaining composites. Kinetics of network formation is investigated by methods of polarization microscopy and integrated small-angle scattering. It is shown that gel-like states of the composite H-37+PMVP+HOBA and 5CB+PEG+HOBA are formed at polymer concentration above 7 percent and 9 percent, correspondingly. The basic electro-optic parameters of the obtained composites are determined at room temperature. Experimental results are explained by phase separation of the system, diminution of a working area of electro-optical effects and influence of areas with high polymer concentration on areas with their low concentration

  16. Micromechanical modeling of the elasto-viscoplastic bahavior of semi-crystalline polymers

    NARCIS (Netherlands)

    Dommelen, van J.A.W.; Parks, D.M.; Boyce, M.C.; Brekelmans, W.A.M.; Baaijens, F.P.T.

    2003-01-01

    A micromechanically-based constitutive model for the elasto-viscoplastic deformationand texture evolution of semi-crystalline polymers is developed. The modelidealizes the microstructure to consist of an aggregate of two-phase layered compositeinclusions. A new framework for the composite inclusion

  17. Stilbene crystalline powder in polymer base as a new fast neutron detector

    International Nuclear Information System (INIS)

    Budakovsky, S.V.; Galunov, N.Z.; Grinyov, B.V.; Karavaeva, N.L.; Kyung Kim, Jong; Kim, Yong-Kyun; Pogorelova, N.V.; Tarasenko, O.A.

    2007-01-01

    A new organic scintillation material consisting of stilbene grains in a polymer glue base is presented. The crystalline grains of stilbene are obtained by mechanical grinding of stilbene single crystals. The resulting composite scintillators have been studied as detectors for fast neutrons

  18. Three-dimensional RF SoP technologies: LTCC versus LCP

    KAUST Repository

    Arabi, Eyad A.

    2014-12-18

    The system on package (SoP) is an emerging platform, introduced to provide enhanced functionality, and immense miniaturization through vertically integrated passive components in a multilayer process. This way the package is not a mere holder or cover but is a functional part of the system. The leading multilayer packaging technologies for SoP designs: low temperature co-fired ceramic (LTCC) and liquid crystal polymer (LCP) are compared in this work for the first time. Passive components and filters have been implemented in both technologies to show the advantages of the three-dimensional nature of these technologies. The comparison results show that parallel plate capacitors implemented in the ultra-thin LCP provides the highest capacitance density. For spiral inductors, conversely, LTCC inductors have the highest inductances while LCP inductors offer the highest self-resonant frequencies and the highest quality factors (Q). In a circuit level, simulated and measured results of a bandpass filter at 1.5 GHz show that both LCP and LTCC can provide similar performances with an incredible size reduction for the case of ultra-thin LCP. Also, the thin LCP filter exhibits a large degree of mechanical flexibility which makes this technology suitable for future flexible modules.

  19. Dielectric properties and conductivity of carbon nanofiber/semi-crystalline polymer composites

    International Nuclear Information System (INIS)

    Sui, G.; Jana, S.; Zhong, W.H.; Fuqua, M.A.; Ulven, C.A.

    2008-01-01

    The properties of semi-crystalline polymer nanocomposites are affected by the nanofillers directly and indirectly, as two phases, i.e., crystalline and amorphous, exist in the polymer. The effects of nanofillers on the two phases could be competitive. The dielectric properties and conductivity of carbon nanofibers (CNF)/semi-crystalline polymer nanocomposites are studied in this paper. CNF/polypropylene (PP) nanocomposites are prepared in experiment by melt blending. The resulting morphology and crystalline structure are characterized by means of differential scanning calorimetry, wide angle X-ray diffraction and scanning electron microscopy. The PP nanocomposite containing 5 wt.% CNF exhibits a surprisingly high dielectric constant under wide sweep frequencies attended by low dielectric loss. Its dielectric constant is >600 under lower frequency, and remains >200 at a frequency of 4000 Hz. The electrical and thermal conductivities of the nanocomposites are studied, and enhancements are seen with increased CNF content. Theoretical analyses on the physical properties are carried out by applying the existing models. Research results indicate that a common commercial plastic with good comprehensive performance, which exhibited the potential for applications in advanced electronics, was obtained by a simple industry benign technique

  20. Properties analysis of tensile strength, crystallinity degree and microstructure of polymer composite polypropylene-sand

    International Nuclear Information System (INIS)

    Sudirman; Karo-Karo, Aloma; Ari-Handayani; Bambang-Sugeng; Rukihati; Mashuri

    2004-01-01

    Materials modification base on polymer toward polymer composite is needed by addition of filler. Mechanical properties such as tensile strength, crystallinity degree and microstructure of polymer composite based on polypropylene with sand filler have been investigated. In this work, the polymer composite has been made by mixing the matrix of polypropylene melt flow 2 (PP MF2) or polypropylene melt flow 10 (PP MF 10) with sand filler in a labo plastomill. The composition of sand filler was varied to 10, 30, 40 and 50 % v/v, a then the composite were casted to the film sheets form. The sheets were characterized mechanically i.e tensile strength, crystallinity degree and microstructure. The result showed that the tensile strength decreased by increasing the volume fraction of sand filler, in accordance with microstructure investigation that the matrix area under zone plastic deformation (more cracks), while the filler experienced elastic deformation, so that the strength mechanism of filler did not achieved with expectation (Danusso and Tieghi theory). For filler more than 30 % of volume fraction, the tensile strength of polypropylene melt flow 10 (PP MF 10) was greater than that polypropylene melt flow 2 (PP MF2). It was caused by plasticities in PP MF 10. The tensile strength of PP MF2 was greater than that PP MF 10 for volume fraction of sand filler less than 30 %. It was caused by PP MF2 to be have more degree of crystallinity

  1. Study and modeling of heat transfer during the solidification of semi-crystalline polymers

    Energy Technology Data Exchange (ETDEWEB)

    Le Goff, R.; Poutot, G.; Delaunay, D. [Laboratoire de Thermocinetique de l' ecole polytechnique de l' universite de Nantes, UMR CNRS 6607, rue Christian Pauc, BP 50609 44306 Nantes cedex 3 (France); Fulchiron, R.; Koscher, E. [Laboratoire des Materiaux Polymeres et des Biomateriaux, IMP/UMR CNRS 5627, Universite Claude Bernard, Lyon 1, 69622 Villeurbanne Cedex (France)

    2005-12-01

    Semi-crystalline polymers are materials whose behavior during their cooling is difficult to model because of the strong coupling between the crystallization, heat transfer, pressure and shear. Thanks to two original apparatus we study solidification of such a polymer without shear. Firstly the comparison between experimental results and a numerical model will permit to validate crystallization kinetic for cooling rate reachable by DSC. The second experiment makes it possible to analyze solidification for high cooling rate, corresponding to some manufacturing processes. It appears that crystallization has an influence on the thermal contact resistance. (author)

  2. Synthesis and characterization of organic-inorganic hybrids formed between conducting polymers and crystalline antimonic acid

    Directory of Open Access Journals (Sweden)

    Beleze Fábio A.

    2001-01-01

    Full Text Available In this paper we report the synthesis and characterization of novel organic-inorganic hybrid materials between the crystalline antimonic acid (CAA and two conductive polymers: polypyrrole and polyaniline. The hybrids were obtained by in situ oxidative polymerization of monomers by the Sb(V present in the pyrochlore-like CAA structure. The materials were characterized by infrared and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, CHN elemental analysis and electronic paramagnetic resonance spectroscopy. The results showed that both polymers were formed in their oxidized form, with the CAA structure acting as a counter anion.

  3. Detection of radiation deformation in crystalline polymers using the speckle photography technique

    International Nuclear Information System (INIS)

    El-Ghandoor, H.; Hashem, A.A.; Sharaf, F.

    1995-01-01

    In order to measure the resulting deformation due to gamma irradiation of polymers, a new optical technique, namely speckle-photography, was established and used. Thin films of tetrafluoroethene, with constant thickness were irradiated by different doses of gamma rays and the diffraction patterns of a laser beam passing through these films were recorded using the speckle photography technique. This technique has been applied to detect the radiation deformation in (Teflon) TFE, which is a crystalline polymer. A diffraction pattern due to the TFE thin layer is obtained and superimposed on the interference pattern displaying the speckle pattern pairs recorded on the same emulsion. (author)

  4. Three-dimensional RF SoP technologies: LTCC versus LCP

    KAUST Repository

    Arabi, Eyad A.; Shamim, Atif

    2014-01-01

    or cover but is a functional part of the system. The leading multilayer packaging technologies for SoP designs: low temperature co-fired ceramic (LTCC) and liquid crystal polymer (LCP) are compared in this work for the first time. Passive components

  5. Studies on the Synthesis,Characterization and Properties of the Reactive Thermotropic Liquid Crystalline Polymer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Introduction Four species of reactive thermotropic liquid crystalline polymer (LCMC) with different relative molecular weight were synthesized in this work (see scheme 1, n=2, 6, 10, ∞.n means number of repeat structure unit). Their structure, morphology and properties were investigated systemically by differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Wide-angle X-ray diffraction (WAXD), polarizing opticalmicroscopy (POM) and ubb...

  6. A new series of two-ring-based side chain liquid crystalline polymers: synthesis and mesophase characterization

    CSIR Research Space (South Africa)

    Reddy, GSM

    2013-05-01

    Full Text Available A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings...

  7. Semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

    Institute of Scientific and Technical Information of China (English)

    Yuxiang Li; Seyeong Song; Song Yi Park; Jin Young Kim; Han Young Woo

    2017-01-01

    Three types of semi-crystalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain organization.The resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular interactions.The optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π stacking.With increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was observed.The siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to (300) for this series of polymers in the grazing incidence wide angle X-ray scattering measurements.The PPsiDTBT,PPsiDTFBT and PPsiDT2FBT devices showed a power conversion efficiency of 3.16%,4.40% and 5.65%,respectively,by blending with PC71BM.Langevin-type bimolecular charge recombination was similar for three polymeric solar cells.The main loss in the photocurrent generation for PPsiDTBT:PC71BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density (Jsc) and open-circuit voltage (Voc).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71BM for further optimizing polymer solar cells.

  8. Effect of Polyamide 6 on Crystalline Structure of Polymer in PVDF-Nanoclay Nanocomposite

    Directory of Open Access Journals (Sweden)

    Ali Akbar Yousefi

    2012-12-01

    Full Text Available The  effect  of  nanocaly  on  crystalline  structure  of  poly(vinylidene  fuoride, PVDF, and the morphology of the resulting nano-composite were investigated using  different  characterization  techniques.  The  presence  of  3wt%  Cloisite 30B in PVDF matrix results in 11 fold increase in the percentage of beta crystalline content of the polymer. This was found to be attributed to the epitaxial effect of the clay  surface. The  beta  crystalline  content  of  the  pure  polymer  (6% was  raised  to 68% in the composite. Addition of 5wt% polyamide 6 (PA6 improved dispersion of nanoclay which led to augmentation of the viscosity and displacement of the crossover frequency of the compatibilized composite towards lower frequencies. However, due to stronger affnity of the PA6 towards organically modifed clay the epitaxial effect of  the  clay on  crystalline  structure of PVDF was  totally  eliminated. The  reduction of  viscosity  in  incompatibilized  nanocomposite was  attributed  to  reduced  number of PVDF chain entanglements  in  the presence of nanoclay. Meanwhile,  increase  in viscosity and displacement of crossover  frequency  towards  lower  frequencies were attributed to formation of clay-PA nanoparticles and PVDF-polyamide 6 interactions. It is expected that the presence of polyamide 6 promotes the formation of oriented-beta crystals in PVDF, which in turn improves the piezoelectric properties of the polymer.

  9. Helium leak testing the Westinghouse LCP coil

    International Nuclear Information System (INIS)

    Merritt, P.A.; Attaar, M.H.; Hordubay, T.D.

    1983-01-01

    The tests, equipment, and techniques used to check the Westinghouse LCP coil for coolant flow path integrity and helium leakage are unique in terms of test sensitivity and application. This paper will discuss the various types of helium leak testing done on the LCP coil as it enters different stages of manufacture. The emphasis will be on the degree of test sensitivity achieved under shop conditions, and what equipment, techniques and tooling are required to achieve this sensitivity (5.9 x 10 -8 scc/sec). Other topics that will be discussed are helium flow and pressure drop testing which is used to detect any restrictions in the flow paths, and the LCP final acceptance test which is the final leak test performed on the coil prior to its being sent for testing. The overall allowable leak rate for this coil is 5 x 10 -6 scc/sec. A general evaluation of helium leak testing experience are included

  10. NATO Advanced Research Workshop on Computational Methods for Polymers and Liquid Crystalline Polymers

    CERN Document Server

    Pasini, Paolo; Žumer, Slobodan; Computer Simulations of Liquid Crystals and Polymers

    2005-01-01

    Liquid crystals, polymers and polymer liquid crystals are soft condensed matter systems of major technological and scientific interest. An understanding of the macroscopic properties of these complex systems and of their many and interesting peculiarities at the molecular level can nowadays only be attained using computer simulations and statistical mechanical theories. Both in the Liquid Crystal and Polymer fields a considerable amount of simulation work has been done in the last few years with various classes of models at different special resolutions, ranging from atomistic to molecular and coarse-grained lattice models. Each of the two fields has developed its own set of tools and specialized procedures and the book aims to provide a state of the art review of the computer simulation studies of polymers and liquid crystals. This is of great importance in view of a potential cross-fertilization between these connected areas which is particularly apparent for a number of experimental systems like, e.g. poly...

  11. Thermomechanical and adhesive properties of radiation-modified polymer composites for thermosetting products

    International Nuclear Information System (INIS)

    Kalkis, V.; Maksimov, R.D.; Kalnins, M.; Zicans, J.; Bocoka, T.; Revjakin, O.

    2000-01-01

    The gamma-irradiated blends of polyethylene (PE) with ethylene / propylene / diene copolymer (Epdm) and thermotropic liquid crystalline polymer (LCP) are investigated. The radiation dose absorbed does not exceed 150 kGy (10 kGy=1 Mrad). It is shown that the even small amounts of LCP added to PE improve the mechanical and operational properties of composites and the thermosetting products made of them. The temperature dependences of the elastics modulus, tension diagrams at a temperature above the PE melting point, and recovery curves of the oriented specimens are presented. The kinetics of thermorelaxation and residual setting stresses upon isometric heating and cooling of the previously oriented composites is studied. The data on the influence of LCP on the adhesion interaction of the blend with steel are obtained. The features of thermomechanical and adhesive properties are discussed and the results of morphological and calorimetric tests are given. (author)

  12. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Hernández, Abelardo; Hur, Su-Mi; Armas-Pérez, Julio; Cruz, Monica; de Pablo, Juan

    2017-03-01

    Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

  13. Langmuir-Blodgett films prepared from pre-formed cholestanic liquid-crystalline polymers

    Energy Technology Data Exchange (ETDEWEB)

    Tundo, P.; Hodge, P.; Valli, L.; Davis, F. (Venice Univ. (Italy). Dip. di Scienze Ambientali Lecce Univ. (Italy). Dip. di Scienza dei Materiali Manchester Univ. (United Kingdom). Dep. of Chemistry)

    1992-01-01

    A series of alternating copolymers of maleic anhydride and a-olefins functionalized through different alkyl chains with cholestanic groups were synthetised and derivatives prepared by reactions of the anhydride residues with methanol, water, dimethylamine and morpholine, respectively. The same starting functionalized a-olefins were used to prepare other suitable compounds in order to correlate the features of the liquid-crystalline behaviour of the mesogenic cholestanic group with the stability of the forthcoming polymeric or not polymeric Langmuir-Blodgett (LB) films. For some copolymers surface pressure against area per molecule isotherms are reported. In some multilayer (LB) films, the spacings between the layers were determined by the detection of BRAGG peaks by X-ray diffraction. The (LB) films of these polymers are closed packed, owing to either the polymeric skeleton or liquid-crystalline interaction.

  14. The effect of calcining temperature on the properties of 0-3 piezoelectric composites of PZT and a liquid crystalline thermosetting polymer

    NARCIS (Netherlands)

    Ende, D.A. van den; Groen, W.A.; Zwaag, S. van der

    2011-01-01

    We report on the optimisation of a recently developed high performance 0-3 piezoelectric composite comprising of the piezoelectric Lead Zirconate Titanate (PZT) powder and a liquid crystalline thermosetting matrix polymer (LCT). The matrix polymer is a liquid crystalline polymer comprising of an

  15. Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

    KAUST Repository

    Heumueller, Thomas; Mateker, William R.; Sachs-Quintana, I. T.; Vandewal, Koen; Bartelt, Jonathan A.; Burke, Timothy M.; Ameri, Tayebeh; Brabec, Christoph J.; McGehee, Michael D.

    2014-01-01

    In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which

  16. Mean-field theory of photoinduced molecular reorientation in azobenzene liquid crystalline side-chain polymers

    DEFF Research Database (Denmark)

    Pedersen, T.G.; Johansen, P.M.

    1997-01-01

    . The theory provides an explanation for the high long-term stability of the photoinduced anisotropy as well as a theoretical prediction of the temporal behavior of photoinduced birefringence. The theoretical results agree favorably with measurements in the entire range of writing intensities used......A novel mean-field theory of photoinduced reorientation and optical anisotropy in liquid crystalline side-chain polymers is presented and compared with experiments, The reorientation mechanism is based on photoinduced trans cis isomerization and a multidomain model of the material is introduced...

  17. Temperature influence in crystallinity of polymer microspheres; Influencia da temperatura na cristalinidade de microesferas polimericas

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Cristiane de P.; Novack, Katia M., E-mail: knovack@iceb.ufop.br [Universidade Federal de Ouro Preto - UFOP, ICEB, DEQUI, Ouro Preto, MG (Brazil)

    2011-07-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  18. Semi-crystalline photovoltaic polymers with siloxane-terminated hybrid side-chains

    Institute of Scientific and Technical Information of China (English)

    Yuxiang Li; Seyeong Song; Song Yi Park; Jin Young Kim; Han Young Woo

    2017-01-01

    Three types of semi-cry stalline photovoltaic polymers were synthesized by incorporating a siloxane-terminated organic/inorganic hybrid side-chain and changing the number of fluorine substituents.A branch point away from a polymer main backbone in the siloxane-containing side-chains and the intra-and/or interchain noncovalent coulombic interactions enhance a chain planarity and facile interchain organization.The resulting polymers formed strongly agglomerated films with high roughness,suggesting strong intermolecular interactions.The optical band gap of ca.1.7 eV was measured for all polymers with a pronounced shoulder peak due to tight π-π stacking.With increasing the fluorine substituents,the frontier energy levels decreased and preferential face-on orientation was observed.The siloxane-terminated side-chains and fluorine substitution promoted the intermolecular packing,showing well resolved lamellar scatterings up to(300) for this series of polymers in the grazing incidence wide angle X-ray scattering measurements.The PPsiDTBT,PPsiDTFBT and PPsiDT2 FBT devices showed a power conversion efficiency of 3.16%,4.40%and 5.65%,respectively,by blending with PC71BM.Langevin-type bimolecular charge recombination was similar for three polymeric solar cells.The main loss in the photocurrent generation for PPsiDTBT:PC71BM was interpreted to originate from the trap assisted charge recombination by measuring light-intensity dependent short-circuit current density(JSC) and open-circuit voltage(VOc).Our results provide a new insight into the rational selection of solubilizing substituents for optimizing crystalline interchain packing with appropriate miscibility with PC71 BM for further optimizing polymer solar cells.

  19. Improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers

    Science.gov (United States)

    Sima, Wenxia; Jiang, Xiongwei; Peng, Qingjun; Sun, Potao

    2018-05-01

    Electrical breakdown is an important physical phenomenon in electrical equipment and electronic devices. Many related models and theories of electrical breakdown have been proposed. However, a widely recognized understanding on the following phenomenon is still lacking: impulse breakdown strength which varies with waveform parameters, decrease in the breakdown strength of AC voltage with increasing frequency, and higher impulse breakdown strength than that of AC. In this work, an improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers is proposed based on the Harmonic oscillator model. Simulation and experimental results show that, the energy of trapped charges obtained from AC stress is higher than that of impulse voltage, and the absorbed activation energy increases with the increase in the electric field frequency. Meanwhile, the frequency-dependent relative dielectric constant ε r and dielectric loss tanδ also affect the absorption of activation energy. The absorbed activation energy and modified trap level synergistically determine the breakdown strength. The mechanism analysis of breakdown strength under various voltage waveforms is consistent with the experimental results. Therefore, the proposed model of activation energy absorption in the present work may provide a new possible method for analyzing and explaining the breakdown phenomenon in semi-crystalline insulating polymers.

  20. Cost-effective computational method for radiation heat transfer in semi-crystalline polymers

    Science.gov (United States)

    Boztepe, Sinan; Gilblas, Rémi; de Almeida, Olivier; Le Maoult, Yannick; Schmidt, Fabrice

    2018-05-01

    This paper introduces a cost-effective numerical model for infrared (IR) heating of semi-crystalline polymers. For the numerical and experimental studies presented here semi-crystalline polyethylene (PE) was used. The optical properties of PE were experimentally analyzed under varying temperature and the obtained results were used as input in the numerical studies. The model was built based on optically homogeneous medium assumption whereas the strong variation in the thermo-optical properties of semi-crystalline PE under heating was taken into account. Thus, the change in the amount radiative energy absorbed by the PE medium was introduced in the model induced by its temperature-dependent thermo-optical properties. The computational study was carried out considering an iterative closed-loop computation, where the absorbed radiation was computed using an in-house developed radiation heat transfer algorithm -RAYHEAT- and the computed results was transferred into the commercial software -COMSOL Multiphysics- for solving transient heat transfer problem to predict temperature field. The predicted temperature field was used to iterate the thermo-optical properties of PE that varies under heating. In order to analyze the accuracy of the numerical model experimental analyses were carried out performing IR-thermographic measurements during the heating of the PE plate. The applicability of the model in terms of computational cost, number of numerical input and accuracy was highlighted.

  1. Smectic order and backbone anisotropy of a side-chain liquid crystalline polymer by Small-Angle Neutron Scattering

    Science.gov (United States)

    Noirez, L.; Pépy, G.; Keller, P.; Benguigui, L.

    1991-07-01

    We have simultaneously measured, for the first time, the extension of the polymer backbone of a side-chain liquid crystalline polymer and the intensity of the 001 Bragg reflection, which gives the smectic order parameter Psi as a function of temperature in the smectic phase. We have qualitatively demonstrated that the more the smectic phase is ordered, the more the polymer backbone is localized between the mesogenic layers. It is shown that the Landau theory allows us to relate the radius of gyration parallel to the magnetic field of the polymer backbone to the smectic order parameter. We also show that the Renz-Warner theory is suitable at low temperatures.

  2. Graphic Interface for LCP2 Optimization Program

    DEFF Research Database (Denmark)

    Nicolae, Taropa Laurentiu; Gaunholt, Hans

    1998-01-01

    This report provides information about the software interface that is programmed for the Optimization Program LCP2. The first part is about the general description of the program followed by a guide for using the interface. The last chapters contain a discussion about problems or futute extension...... of the project. The program is written in Visual C++5.0 on a Windows NT4.0 operating system.......This report provides information about the software interface that is programmed for the Optimization Program LCP2. The first part is about the general description of the program followed by a guide for using the interface. The last chapters contain a discussion about problems or futute extensions...

  3. Comparison of filters: Inkjet printed on PEN substrate versus a laser-etched on LCP substrate

    KAUST Repository

    Arabi, Eyad A.

    2014-10-01

    In this paper, microstrip-based bandpass filters on polyethylene naphthalate (PEN) and liquid crystal polymers (LCP) are presented to investigate the performance of filters on ultra-thin substrates. PEN (with a thickness of 120 μm) has been characterized and used for a filter for the first time. In addition to being low cost and transparent, it demonstrates comparable RF performance to LCP. The conductor losses are compared by fabricating filters with inkjet printed lines as well as laser etched copper clad LCP sheets. With 5 layers of inkjet printing, and a curing temperature below 200°C, a final silver thickness of 2 μm and conductivity of 9.6 × 106 S/m are achieved. The designs are investigated at two frequencies, 24 GHz as well as 5 GHz to assess their performance at high and low frequencies respectively. The 24 GHz inkjet printed filter shows an insertion loss of 2 dB, while the 5 GHz design gives an insertion loss of 8 dB. We find that thin substrates have a strong effect on the insertion loss of filters especially as the frequency is reduced. The same design, realized on LCP (thickness of 100 μm) through laser etching, demonstrates a very similar performance, thus verifying this finding. © 2014 European Microwave Association.

  4. Comparison of filters: Inkjet printed on PEN substrate versus a laser-etched on LCP substrate

    KAUST Repository

    Arabi, Eyad A.; McKerricher, Garret; Shamim, Atif

    2014-01-01

    In this paper, microstrip-based bandpass filters on polyethylene naphthalate (PEN) and liquid crystal polymers (LCP) are presented to investigate the performance of filters on ultra-thin substrates. PEN (with a thickness of 120 μm) has been characterized and used for a filter for the first time. In addition to being low cost and transparent, it demonstrates comparable RF performance to LCP. The conductor losses are compared by fabricating filters with inkjet printed lines as well as laser etched copper clad LCP sheets. With 5 layers of inkjet printing, and a curing temperature below 200°C, a final silver thickness of 2 μm and conductivity of 9.6 × 106 S/m are achieved. The designs are investigated at two frequencies, 24 GHz as well as 5 GHz to assess their performance at high and low frequencies respectively. The 24 GHz inkjet printed filter shows an insertion loss of 2 dB, while the 5 GHz design gives an insertion loss of 8 dB. We find that thin substrates have a strong effect on the insertion loss of filters especially as the frequency is reduced. The same design, realized on LCP (thickness of 100 μm) through laser etching, demonstrates a very similar performance, thus verifying this finding. © 2014 European Microwave Association.

  5. Molecular orientation of individual LCP particles in injection-moulded PPS/LCP blends

    Directory of Open Access Journals (Sweden)

    Kestenbach H.-J.

    2003-01-01

    Full Text Available Polarized light microscopy was used to investigate the presence of preferred molecular orientation in the LCP phase of PPS/LCP blends after injection moulding. Normal birefringence effects appeared to be complicated by artifacts due to sample preparation and by the complex nature of polarized light transmission through a multicomponent sample. It was found, however, that, during low-temperature cutting of optically transparent thin sections on a standard microtome, individual LCP particles could be separated from the PPS matrix, and their birefringence analyzed separately. Preferred orientation was detected only in LCP fibrils which dominated in skin regions, but not in droplet-shaped particles which had formed in core regions. Quantitative measurements indicated that the molecular orientation of the fibrils increased linearly with their length-to-diameter aspect ratios which ranged from 15 to 50. Even for the highest aspect ratios, however, the degree of orientation was always less than that which could easily be introduced into pure LCP thin-film samples by manual shearing.

  6. Structure-Property Relationships in Polymer Derived Amorphous/Nano-Crystalline Silicon Carbide for Nuclear Applications

    International Nuclear Information System (INIS)

    Zunjarrao, Suraj C.; Singh, Abhishek K.; Singh, Raman P.

    2006-01-01

    Silicon carbide (SiC) is a promising candidate for several applications in nuclear reactors owing to its high thermal conductivity, high melting temperature, good chemical stability, and resistance to swelling under heavy ion bombardment. However, fabricating SiC by traditional powder processing route generally requires very high temperatures for pressureless sintering. Polymer derived ceramic materials offer unique advantages such as ability to fabricate net shaped components, incorporate reinforcements and relatively low processing temperatures. Furthermore, for SiC based ceramics fabricated using polymer infiltration process (PIP), the microstructure can be tailored by controlling the processing parameters, to get an amorphous, nanocrystalline or crystalline SiC. In this work, fabrication of polymer derived amorphous and nano-grained SiC is presented and its application as an in-core material is explored. Monolithic SiC samples are fabricated by controlled pyrolysis of allyl-hydrido-poly-carbo-silane (AHPCS) under inert atmosphere. Chemical changes, phase transformations and microstructural changes occurring during the pyrolysis process are studied as a function of the processing temperature. Polymer cross-linking and polymer to ceramic conversion is studied using infrared spectroscopy (FTIR). Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are performed to monitor the mass loss and phase change as a function of temperature. X-ray diffraction studies are done to study the intermediate phases and microstructural changes. Variation in density is carefully monitored as a function of processing temperature. Owing to shrinkage and gas evolution during pyrolysis, precursor derived ceramics are inherently porous and composite fabrication typically involves repeated cycles of polymer re-infiltration and pyrolysis. However, there is a limit to the densification that can be achieved by this method and porosity in the final materials presents

  7. Development of orodispersible polymer films with focus on the solid state characterization of crystalline loperamide.

    Science.gov (United States)

    Woertz, Christina; Kleinebudde, Peter

    2015-08-01

    The formulation of active pharmaceutical ingredients (API) as orodispersible films is gaining interest among novel oral drug delivery systems due to their small size, enhanced flexibility and improved patient compliance. The aim of this work was the preparation and characterization of orodispersible films containing loperamide hydrochloride (LPH) as model drug. As loperamide hydrochloride is poorly soluble in water it was used in crystalline form with a loading of 2mg/6cm(2) film. Hydroxypropyl methylcellulose (HPMC) and different types of hydroxypropyl cellulose (HPC) in different concentrations were used as film forming polymers whereas arabic gum, xanthan gum and tragacanth served as thickening agents. Films were characterized with respect to the content uniformity, morphology, thermal behavior and crystallinity. Suspensions were investigated regarding their viscosity using a rotational rheometer and the crystal structure of the Active Pharmaceutical Ingredient (API) was analyzed using polarized light microscopy. The development of flexible, non-brittle and homogeneous films of LPH was feasible. Two polymorphic forms of LPH appeared in the film formulations dependent on the utilized polymer. While in presence of HPMC the original polymorphic form I remained stable in suspension and films, the polymorphic form II occurred in presence of HPC. Both polymorphic forms were prepared separately and a solid state characterization was performed. Polymorph I showed isometric crystals whereas polymorph II showed needle shaped crystals. Tragacanth was able to prevent the transformation to polymorph II, if it was dissolved first before HPC. When HPC was added first to the suspension, the conversion to form II occurred irreversibly also after further addition of tragacanth. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Miniaturized and Ferrite Based Tunable Bandpass Filters in LCP and LTCC Technologies for SoP Applications

    KAUST Repository

    Arabi, Eyad A.

    2015-01-01

    , namely low temperature co-fired ceramic (LTCC) and the liquid crystal polymers (LCP) is demonstrated. The miniaturized filter is based on a second order topology, which has been modified to improve the selectivity and out-of-band rejection without

  9. Selecting polymers for two-phase partitioning bioreactors (TPPBs): Consideration of thermodynamic affinity, crystallinity, and glass transition temperature.

    Science.gov (United States)

    Bacon, Stuart L; Peterson, Eric C; Daugulis, Andrew J; Parent, J Scott

    2015-01-01

    Two-phase partitioning bioreactor technology involves the use of a secondary immiscible phase to lower the concentration of cytotoxic solutes in the fermentation broth to subinhibitory levels. Although polymeric absorbents have attracted recent interest due to their low cost and biocompatibility, material selection requires the consideration of properties beyond those of small molecule absorbents (i.e., immiscible organic solvents). These include a polymer's (1) thermodynamic affinity for the target compound, (2) degree of crystallinity (wc ), and (3) glass transition temperature (Tg ). We have examined the capability of three thermodynamic models to predict the partition coefficient (PC) for n-butyric acid, a fermentation product, in 15 polymers. Whereas PC predictions for amorphous materials had an average absolute deviation (AAD) of ≥16%, predictions for semicrystalline polymers were less accurate (AAD ≥ 30%). Prediction errors were associated with uncertainties in determining the degree of crystallinity within a polymer and the effect of absorbed water on n-butyric acid partitioning. Further complications were found to arise for semicrystalline polymers, wherein strongly interacting solutes increased the polymer's absorptive capacity by actually dissolving the crystalline fraction. Finally, we determined that diffusion limitations may occur for polymers operating near their Tg , and that the Tg can be reduced by plasticization by water and/or solute. This study has demonstrated the impact of basic material properties that affects the performance of polymers as sequestering phases in TPPBs, and reflects the additional complexity of polymers that must be taken into account in material selection. © 2015 American Institute of Chemical Engineers.

  10. Roll-to-Roll printed large-area all-polymer solar cells with 5% efficiency based on a low crystallinity conjugated polymer blend

    Science.gov (United States)

    Gu, Xiaodan; Zhou, Yan; Gu, Kevin; Kurosawa, Tadanori; Yan, Hongping; Wang, Cheng; Toney, Micheal; Bao, Zhenan

    The challenge of continuous printing in high efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. We present a materials design concept for achieving large-area, solution coated all-polymer bulk heterojunction (BHJ) solar cells with stable phase separation morphology between the donor and acceptor. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, our results showed that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers. This methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. We were able to continuously roll-to-roll slot die print large area all-polymer solar cells with power conversion efficiencies of 5%, with combined cell area up to 10 cm2. This is among the highest efficiencies realized with R2R coated active layer organic materials on flexible substrate. DOE BRIDGE sunshot program. Office of Naval Research.

  11. Liquid crystalline polymers IX Main chain thermotropic poly (azomethine – ethers containing thiazole moiety linked with polymethylene spacers

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available A new homologous series of thermally stable thermotropic liquid crystalline poly(azomethine-ethers based on thiazole moiety were synthesized by solution polycondensation of 4,4`-diformyl-α,ω-diphenoxyalkanes, I–IV or 4,4`-diformyl-2,2`-dimethoxy-α,ω-diphenoxyalkanes V–VIII with the new bis(2-aminothiazole monomer X. A model compound XI was synthesized from X with benzaldehyde and characterized by elemental and spectral analyses. The inherent viscosities of the resulting polymers were in the range 0.43–1.34 dI/g. All the poly(azomethine-ethers were insoluble in common organic solvents but dissolved completely in concentrated H2SO4 and formic acid. The mesomorphic properties of these polymers were studied as a function of the diphenoxyalkane space length. Their thermotropic liquid crystalline properties were examined by DSC and optical polarizing microscopy and demonstrated that the resulting polymers form nematic mesophases over wide temperature ranges. The thermogravimetric analyses of those polymers were evaluated by TGA and DSC measurements and correlated to their structural units. X-ray analysis showed that polymers having some degree of crystallinity in the region 2θ = 5–60°. In addition, the morphological properties of selected examples were tested by scanning electron microscopy.

  12. Small Angle Neutron Scattering Studies on Blends of Poly (Styrene-ran-Vinyl Phenol) with Liquid Crystalline Polyurethane

    Science.gov (United States)

    Mehta, Rujul

    2005-03-01

    Molecular composites, composed of uniformly dispersed rigid-rod liquid crystalline polymer (LCP) molecules in a flexible amorphous polymer matrix, have remained hitherto elusive due to a scarcity of miscible systems containing a LCP and an amorphous polymer. The production of such a blend, with an experimentally accessible miscibility window, has become possible by modifying the architecture of the flexible polymer, so as to induce favorable intermolecular hydrogen bonding. Specifically, liquid crystalline polyurethanes (LCPU) are found to be miscible with a copolymer of styrene and vinyl phenol; with optimum hydrogen bonding between the carbonyl groups of the urethane linkages and the hydroxyl groups present in the styrenic matrix. Availability of a truly miscible molecular composite presents a unique opportunity of studying the confirmation of polymer chains containing rigid-rods that are uniformly dispersed in a flexible coil matrix. A system consisting of the LCPU and the deuterated styrenic copolymer containing 20% vinyl phenol is examined by Small Angle Neutron Scattering at the National Center for Neutron Research at Gaithersburg and Technology, and the Institute of Solid State Research (IFF) at Jülich. Scattering curves for neat dPS-VPh did not fit the Debye-Bueche model; indicating complex structure. A two correlation length Debye-Bueche model was considered to accommodate for this nonlinear behavior. This model utilizes four fitting parameters, including two correlation lengths a1 and a2, corresponding to a Debye-Bueche model and Guinier model.

  13. Effect of MWNTs and SiC-Coated MWNTs on Properties of PEEK/LCP Blend

    Directory of Open Access Journals (Sweden)

    Ganesh Chandra Nayak

    2009-01-01

    Full Text Available Multiwall carbon nanotubes (MWNTs were modified with polycarbosilane-derived silicon carbide (SiC to improve its dispersion in the polymer matrix. PEEK/LCP/MWNTs nanocomposites were prepared by melt blending. TEM images show the improved dispersion of SiC-coated MWNTs against agglomerated structure of pure MWNTs in the blend. FESEM images shows better fibrillation of LCP in presence of SiC-coated MWNTs. TGA reveals that nanocomposites with SiC-coated MWNTs shows higher thermal stability than MWNTs filled blend system. Based on enhanced dispersion, storage modulus, tensile modulus and tensile strength were increased drastically with the incorporation of SiC-coated MWNTs. Glass transition temperature of the nanocomposites shows significant improvement with the incorporation of MWNTs.

  14. Pulse coil concepts for the LCP Facility

    International Nuclear Information System (INIS)

    Nelson, B.E.; Burn, P.B.

    1977-01-01

    The pulse coils described in this paper are resistive copper magnets driven by time-varying currents. They are included in the Large Coil Test Facility (LCTF) portion of the Large Coil Program (LCP) to simulate the pulsed field environment of the toroidal coils in a tokamak reactor. Since TNS (a 150 sec, 5MA, igniting tokamak) and the Oak Ridge EPR (Experimental Power Reactor) are representative of the first tokamaks to require the technology developed in LCP, the reference designs for these machines, especially TNS, are used to derive the magnetic criteria for the pulse coils. This criteria includes the magnitude, distribution, and rate of change of pulsed fields in the toroidal coil windings. Three pulse coil concepts are evaluated on the basis of magnetic criteria and factors such as versatility of design, ease of fabrication and cost of operation. The three concepts include (1) a pair of poloidal coils outside the LCTF torus, (2) a single poloidal coil threaded through the torus, and (3) a pair of vertical axis coil windings inside the bore of one or more of the toroidal test coils

  15. Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers

    Directory of Open Access Journals (Sweden)

    Ángela B. Sifontes

    2015-01-01

    Full Text Available Here we report the synthesis of barium sulphate (BaSO4 nanoparticles from Ba(OH2/BaCl2 solutions by a combined method of precipitation and quenching in absence of polymer stabilizers. Transmission electron microscopy (HRTEM, Fourier transforms infrared spectroscopy (FTIR, and X-ray diffraction (XRD were employed to characterize the particles. The Scherrer formula was applied to estimate the particle size using the width of the diffraction peaks. The obtained results indicate that the synthesized material is mainly composed of nanocrystalline barite, with nearly spherical morphology, and diameters ranging from 4 to 92 nm. The lattice images of nanoparticles were clearly observed by HRTEM, indicating a high degree of crystallinity and phase purity. In addition, agglomerates with diameters between 20 and 300 nm were observed in both lattice images and dynamic light scattering measurements. The latter allowed obtaining the particle size distribution, the evolution of the aggregate size in time of BaSO4 in aqueous solutions, and the sedimentation rate of these solutions from turbidimetry measurements. A short discussion on the possible medical applications is presented.

  16. LCP nanoparticle for tumor and lymph node metastasis imaging

    Science.gov (United States)

    Tseng, Yu-Cheng

    A lipid/calcium/phosphate (LCP) nanoparticle formulation (particle diameter ˜25 nm) has previously been developed to delivery siRNA with superior efficiency. In this work, 111In was formulated into LCP nanoparticles to form 111In-LCP for SPECT/CT imaging. With necessary modifications and improvements of the LCP core-washing and surface-coating methods, 111In-LCP grafted with polyethylene glycol exhibited reduced uptake by the mononuclear phagocytic system. SPECT/CT imaging supported performed biodistribution studies, showing clear tumor images with accumulation of 8% or higher injected dose per gram tissue (ID/g) in subcutaneous, human-H460, lung-cancer xenograft and mouse-4T1, breast cancer metastasis models. Both the liver and the spleen accumulated ˜20% ID/g. Accumulation in the tumor was limited by the enhanced permeation and retention effect and was independent of the presence of a targeting ligand. A surprisingly high accumulation in the lymph nodes (˜70% ID/g) was observed. In the 4T1 lymph node metastasis model, the capability of intravenously injected 111In-LCP to visualize the size-enlarged and tumor-loaded sentinel lymph node was demonstrated. By analyzing the SPECT/CT images taken at different time points, the PK profiles of 111In-LCP in the blood and major organs were determined. The results indicated that the decrement of 111In-LCP blood concentration was not due to excretion, but to tissue penetration, leading to lymphatic accumulation. Larger LCP (diameter ˜65 nm) nanoparticles were also prepared for the purpose of comparison. Results indicated that larger LCP achieved slightly lower accumulation in the tumor and lymph nodes, but much higher accumulation in the liver and spleen; thus, larger nanoparticles might not be favorable for imaging purposes. We also demonstrated that LCP with a diameter of ˜25 nm were better able to penetrate into tissues, travel in the lymphatic system and preferentially accumulate in the lymph nodes due to 1) small

  17. Graphene based strain sensor with LCP substrate

    Science.gov (United States)

    Nie, M.; Yang, H. S.; Xia, Y. H.

    2018-02-01

    A flexible strain sensor constructed by an efficient, low-cost fabrication strategy is presented in this paper. It is assembled by adhering grid-like graphene on LCP substrate. Kinds of measurement setup have been designed to verify that the proposed flexible sensor device is suitable to be used in health monitoring system. From the experiment results, it can be proved that the sensor exhibits the following features: ultra-light, relatively good sensitivity, high reversibility, superior physical robustness, easy fabrication. With the great performance of this flexible strain sensor, it is considered to play an important role in body monitoring, structural health monitoring system, fatigue detection and healthcare systems in the near future.

  18. Prediction and design of first super-strong liquid-crystalline polymers

    International Nuclear Information System (INIS)

    Dowell, F.

    1989-01-01

    This paper presents the details of the theoretical prediction and design (atom by atom, bond by bond) of the molecule chemical structures of the first candidate super-strong liquid-crystalline polymers (SS LCPs). These LCPs are the first LCPs designed to have good compressive strengths, as well as to have tensile strengths and tensile moduli significantly larger than those of existing strong LCPs (such as Kevlar). The key feature of this new class of LCPs is that the exceptional strength is three dimensional on a microscopic, molecular level (thus, on a macroscopic level), in contrast to present LCPs (such as Kevlar) with their one-dimensional exceptional strength. These SS LCPs also have some solubility and processing advantages over existing strong LCPs. These SS LCPs are specially-designed combined LCPs such that the side chains of a molecule interdigitate with the side chains of other molecules. This paper also presents other essential general and specific features required for SS LCPs. Considerations in the design of SS LCPs include the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and side chains, the degree of polymerization, the length of the side chains, the regularity of spacing of the side chains along the backbone, the interdigitation of side chains in submolecular strips, the packing of the side chains on one or two sides of the backbone, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and side chains for easy alignment

  19. On the molecular anisotropy of liquid crystalline and flexible polymer systems

    Science.gov (United States)

    van Horn, Brett L.

    The demand for products of ever increasing quality or for novel applications has required increasing attention to or manipulation of the anisotropy of manufactured parts. Oriented plastics are used everywhere from recording film to automotive body parts to monofilament fishing line. Liquid crystals are also used in a wide array of applications including their dominance in the flat panel display industry, color changing temperature sensors, and woven bullet resistant fabrics. Anisotropy can also be detrimental, for instance sometimes leading to poor fracture resistance or low yield stress along specific directions. Controlling and measuring anisotropy of materials has become increasingly important, but doing so is wrought with challenges. Measuring physical properties of isotropic liquids, such as water or most oils can be done in a straightforward fashion. Their viscosities and densities, for example, have unique values under a given set of conditions. With anisotropic fluids, like liquid crystals, the viscosity, for instance, will not only depend upon temperature, concentration, etc. but also upon the direction of observation, degree of anisotropy, source of anisotropy, and so forth. This added degree of complexity complicates our ability to define the state of the material at which the measurements are made and generally necessitates the use of more sophisticated measurement strategies or techniques. This work presents techniques and tools for investigating anisotropy in liquid crystalline and stretched polymeric systems. Included are the use of conoscopy for the determination of birefringence and orientation of nematic liquid crystals and stretched polymers, the shear response of flow aligning nematic liquid crystal monodomains, and the design of a novel linear rheometer that allows for in situ optical or scattering investigations.

  20. Fuzzy set implementation for controlling and evaluation of factors affecting melting, crystallinity and interaction in polymer blends

    International Nuclear Information System (INIS)

    Al-Rawajfeh, Aiman Eid; Mamlook, Rustom

    2008-01-01

    In this study, the factors (i.e. weight fractions, crystallization temperatures and interaction such as hydrogen bonding) affecting melting, crystallinity, interaction parameters and miscibility of polymer blends (PB) have been studied by implementation of a fuzzy set. The interaction parameters were calculated using the Nishi-Wang equation, which is based on the Flory-Huggins theory. The values of interaction parameters χ 12 were negative for all blend compositions suggesting that χ 12 depends on the volume fraction (Φ) of the polymer. The various characteristics for the case study was synthesized and converted into relative weights w.r.t fuzzy set method. The fuzzy set analysis for the case study reveal increase as confirmed by the experimental data. The application of the fuzzy set methodology offers reasonable prediction and assessment for detecting yield in polymer blends

  1. Research and development activity in support of LCP

    International Nuclear Information System (INIS)

    Lubell, M.S.

    1979-01-01

    The research and development activity (RDAC) established in support of the Large Coil Program (LCP) at Oak Ridge National Laboratory (ORNL) is described. Some experimental results are presented and the importance of the RDAC to the magnet community is discussed

  2. Processing-microstructure relationships in thermotropic liquid crystalline polymers: Experimental and numerical modeling studies

    Science.gov (United States)

    Fang, Jun

    Thermotropic liquid crystalline polymers (TLCPs) are a class of promising engineering materials for high-demanding structural applications. Their excellent mechanical properties are highly correlated to the underlying molecular orientation states, which may be affected by complex flow fields during melt processing. Thus, understanding and eventually predicting how processing flows impact molecular orientation is a critical step towards rational design work in order to achieve favorable, balanced physical properties in finished products. This thesis aims to develop deeper understanding of orientation development in commercial TLCPs during processing by coordinating extensive experimental measurements with numerical computations. In situ measurements of orientation development of LCPs during processing are a focal point of this thesis. An x-ray capable injection molding apparatus is enhanced and utilized for time-resolved measurements of orientation development in multiple commercial TLCPs during injection molding. Ex situ wide angle x-ray scattering is also employed for more thorough characterization of molecular orientation distributions in molded plaques. Incompletely injection molded plaques ("short shots") are studied to gain further insights into the intermediate orientation states during mold filling. Finally, two surface orientation characterization techniques, near edge x-ray absorption fine structure (NEXAFS) and infrared attenuated total reflectance (FTIR-ATR) are combined to investigate the surface orientation distribution of injection molded plaques. Surface orientation states are found to be vastly different from their bulk counterparts due to different kinematics involved in mold filling. In general, complex distributions of orientation in molded plaques reflect the spatially varying competition between shear and extension during mold filling. To complement these experimental measurements, numerical calculations based on the Larson-Doi polydomain model

  3. Functionalized Nanoporous Polymer Membranes with Well-Defined Pore Architectures via Lyotropic Liquid-Crystalline Monomers

    National Research Council Canada - National Science Library

    Gin, Douglas

    1997-01-01

    .... Two lyotropic liquid-crystalline monomer platforms have been synthesized. The interchannel separations in the polymerizable materials can be varied in the 30-40 A range by the choice of counterion on the ionic headgroup of the monomers...

  4. Welding behavior of semi-crystalline polymers 2. The effect of cocrystallisation on autoadhesion

    NARCIS (Netherlands)

    Xue, Y.-Q.; Tervoort, T.A.; Rastogi, S.; Lemstra, P.J.

    2000-01-01

    The effect of cocrystallization on the welding behavior of semicrystalline polymers was studied by means of T-peel testing at room temperature, using ultrahigh-molecular-weight polyethylene (UHMWPE) as a model polymer. Solution-cast films of UHMWPE have a very special morphology, consisting of

  5. Influence of the nematic order on the rheology and conformation of stretched comb-like liquid crystalline polymers

    Science.gov (United States)

    Fourmaux-Demange, V.; Brûlet, A.; Boué, F.; Davidson, P.; Keller, P.; Cotton, J. P.

    2000-04-01

    We have studied the rheology and the conformation of stretched comb-like liquid-crystalline polymers. Both the influence of the comb-like structure and the specific effect of the nematic interaction on the dynamics are investigated. For this purpose, two isomers of a comb-like polymetacrylate polymer, of well-defined molecular weights, were synthesized: one displays a nematic phase over a wide range of temperature, the other one has only an isotropic phase. Even with high degrees of polymerization N, between 40 and 1000, the polymer chains studied were not entangled. The stress-strain curves during the stretching and relaxation processes show differences between the isotropic and nematic comb-like polymers. They suggest that, in the nematic phase, the chain dynamics is more cooperative than for a usual linear polymer. Small-angle neutron scattering has been used in order to determine the evolution of the chain conformation after stretching, as a function of the duration of relaxation t_r. The conformation can be described with two parameters only: λ_p, the global deformation of the polymer chain, and p, the number of statistical units of locally relaxed sub-chains. For the comb-like polymer, the chain deformation is pseudo-affine: λ_p is always smaller than λ (the deformation ratio of the whole sample). In the isotropic phase, λ_p has a constant value, while p increases as t_r. This latter behavior is not that expected for non-entangled chains, in which p varies as {t_r}^{1/2} (Rouse model). In the nematic phase, λ_p decreases as a stretched exponential function of t_r, while p remains constant. The dynamics of the comb-like polymers is discussed in terms of living clusters from which junctions are produced by interactions between side chains. The nematic interaction increases the lifetime of these junctions and, strikingly, the relaxation is the same at all scales of the whole polymer chain.

  6. Highly mesoporous single-crystalline zeolite beta synthesized using a nonsurfactant cationic polymer as a dual-function template

    KAUST Repository

    Zhu, Jie

    2014-02-12

    Mesoporous zeolites are useful solid catalysts for conversion of bulky molecules because they offer fast mass transfer along with size and shape selectivity. We report here the successful synthesis of mesoporous aluminosilicate zeolite Beta from a commercial cationic polymer that acts as a dual-function template to generate zeolitic micropores and mesopores simultaneously. This is the first demonstration of a single nonsurfactant polymer acting as such a template. Using high-resolution electron microscopy and tomography, we discovered that the resulting material (Beta-MS) has abundant and highly interconnected mesopores. More importantly, we demonstrated using a three-dimensional electron diffraction technique that each Beta-MS particle is a single crystal, whereas most previously reported mesoporous zeolites are comprised of nanosized zeolitic grains with random orientations. The use of nonsurfactant templates is essential to gaining single-crystalline mesoporous zeolites. The single-crystalline nature endows Beta-MS with better hydrothermal stability compared with surfactant-derived mesoporous zeolite Beta. Beta-MS also exhibited remarkably higher catalytic activity than did conventional zeolite Beta in acid-catalyzed reactions involving large molecules. © 2014 American Chemical Society.

  7. Towards the understanding of the molecular weight dependence of essential work of fracture in semi-crystalline polymers: A study on poly(ε-caprolactone

    Directory of Open Access Journals (Sweden)

    F. Tuba

    2014-11-01

    Full Text Available The plane-stress ductile fracture of poly(#-caprolactone (PCL has been investigated as a function of molecular weight and related crystalline structure. Because of the interacting effects in semi-crystalline polymers a separate study of a given structural parameter is rather challenging. Nevertheless, this polymer seems to be a good model material to study the effect of molecular weight on the essential work of fracture, as the interactions between the separate parameters, at room temperature, are negligible. The molecular characteristics of PCL were determined by size exclusion chromatography. To confirm the entangled molecular structure of studied polymers rheological measurements were performed. The crystalline morphology has been characterized by differential scanning calorimetry and wide angle X-ray diffraction. Quasi-static tensile tests and essential work of fracture tests were performed to study the mechanical behavior. Based on the experimental observations an empirical model has been proposed to outline the molecular weight and crystallinity dependence of the essential work of fracture in this semi-crystalline polymer.

  8. Small Molecule Acceptor and Polymer Donor Crystallinity and Aggregation Effects on Microstructure Templating: Understanding Photovoltaic Response in Fullerene-Free Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, Nicholas D.; Dudnik, Alexander S.; Aldrich, Thomas J.; Manley, Eric F.; Fauvell, Thomas J.; Hartnett, Patrick E.; Wasielewski, Michael R.; Chen, Lin X.; Melkonyan, Ferdinand S.; Facchetti, Antonio; Chang, Robert P. H.; Marks, Tobin J.

    2017-05-10

    Perylenediimide (PDI) small molecule acceptor (SMA) crystallinity and donor polymer aggregation and crystallinity effects on bulk-heterojunction microstructure and polymer solar cell (PSC) performance are systematically investigated. Two highperformance polymers, semicrystalline poly[5-(2-hexyldodecyl)-4Hthieno[3,4-c]pyrrole-4,6(5H)-dione-1,3-yl-alt-4,4''dodecyl-2,2':5',2''- terthiophene-5,5''-diyl] (PTPD3T or D1) and amorphous poly{4,8- bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene- 2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-2-carboxylate-2,6-diyl) (PBDTT-FTTE or D2), are paired with three PDI-based SMAs (A1-A3) of differing crystallinity (A1 is the most, A3 is the least crystalline). The resulting PSC performance trends are strikingly different from those of typical fullerene-based PSCs and are highly material-dependent. The present trends reflect synergistic aggregation propensities between the SMA and polymer components. Importantly, the active layer morphology is templated by the PDI in some blends and by the polymer in others, with the latter largely governed by the polymer aggregation. Thus, PTPD3T templating capacity increases as self-aggregation increases (greater Mn), optimizing PSC performance with A2, while A3-based cells exhibit an inverse relationship between polymer aggregation and performance, which is dramatically different from fullerene-based PSCs. For PBDTT-FTTE, A2-based cells again deliver the highest PCEs of ~5%, but here both A2 and PBDTT-FTTE (medium Mn) template the morphology. Overall, the present results underscore the importance of nonfullerene acceptor aggregation for optimizing PSC performance and offer guidelines for pairing SMAs with acceptable donor polymers.

  9. Enhanced drug delivery capabilities from stents coated with absorbable polymer and crystalline drug

    OpenAIRE

    Carlyle, Wenda C.; McClain, James B.; Tzafriri, Abraham R.; Bailey, Lynn; Zani, Brett G.; Markham, Peter M.; Stanley, James R.L.; Edelman, Elazer R.

    2012-01-01

    Current drug eluting stent (DES) technology is not optimized with regard to the pharmacokinetics of drug delivery. A novel, absorbable-coating sirolimus-eluting stent (AC-SES) was evaluated for its capacity to deliver drug more evenly within the intimal area rather than concentrating drug around the stent struts and for its ability to match coating erosion with drug release. The coating consisted of absorbable poly-lactide-co-glycolic acid (PLGA) and crystalline sirolimus deposited by a dry-p...

  10. New theories for smectic and nematic liquid-crystal polymers: Backbone LCPs [liquid crystalline polymers] and their mixtures and side-chain LCPs

    International Nuclear Information System (INIS)

    Dowell, F.

    1987-01-01

    A summary of predictions and explanations from statistical-physics theories for both backbone and side-chain liquid crystalline polymers (LCPs) and for mixtures with backbone LCPs are presented. Trends in the thermodynamic and molecular ordering properties have been calculated as a function of pressure, density, temperature, and molecule chemical structures (including degree of polymerization and the following properties of the chemical structures of the repeat units: lengths and shapes, intra-chain rotation energies, dipole moments, site-site polarizabilities and Lennard-Jones potentials, etc.) in nematic and multiple smectic-A LC phases and in the isotropic liquid phase. The theoretical results are found to be in good agreement with existing experimental data. These theories can also be applied to combined LCPs. Since these theories have no ad hoc or arbitrarily adjustable parameters, these theories can be used to design new LCPs and new solvents as well as to predict and explain properties. 27 refs., 4 tabs

  11. Ionic conductivity studies in crystalline PVA/NaAlg polymer blend electrolyte doped with alkali salt KCl

    Science.gov (United States)

    Sheela, T.; Bhajantri, R. F.; Ravindrachary, V.; Pujari, P. K.; Rathod, Sunil G.; Naik, Jagadish

    2014-04-01

    Potassium Chloride (KCl) doped poly(vinyl alcohol) (PVA)/sodium alginate (NaAlg) in 60:40 wt% polymer blend electrolytes were prepared by solution casting method. The complexation of KCl with host PVA/NaAlg blend is confirmed by FTIR and UV-Vis spectra. The XRD studies show that the crystallinity of the prepared blends increases with increase in doping. The dc conductivity increases with increase in dopant concentration. Temperature dependent dc conductivity shows an Arrhenius behavior. The dielectric properties show that both the dielectric constant and dielectric loss increases with increase in KCl doping concentration and decreases with frequency. The cole-cole plots show a decrease in bulk resistance, indicates the increase in ac conductivity, due to increase in charge carrier mobility. The doping of KCl enhances the mechanical properties of PVA/NaAlg, such as Young's modulus, tensile strength, stiffness.

  12. Study of the Transformations of Micro/Nano-crystalline Acetaminophen Polymorphs in Drug-Polymer Binary Mixtures.

    Science.gov (United States)

    Maniruzzaman, Mohammed; Lam, Matthew; Molina, Carlos; Nokhodchi, Ali

    2017-07-01

    This study elucidates the physical properties of sono-crystallised micro/nano-sized acetaminophen/paracetamol (PMOL) and monitors its possible transformation from polymorphic form I (monoclinic) to form II (orthorhombic). Hydrophilic Plasdone® S630 copovidone (S630), N-vinyl-2-pyrrolidone and vinyl acetate copolymer, and methacrylate-based cationic copolymer, Eudragit® EPO (EPO), were used as polymeric carriers to prepare drug/polymer binary mixtures. Commercially available PMOL was crystallised under ultra sound sonication to produce micro/nano-sized (0.2-10 microns) crystals in monoclinic form. Homogeneous binary blends of drug-polymer mixtures at various drug concentrations were obtained via a thorough mixing. The analysis conducted via the single X-ray crystallography determined the detailed structure of the crystallised PMOL in its monoclinic form. The solid state and the morphology analyses of the PMOL in the binary blends evaluated via differential scanning calorimetry (DSC), modulated temperature DSC (MTDSC), scanning electron microscopy (SEM) and hot stage microscopy (HSM) revealed the crystalline existence of the drug within the amorphous polymeric matrices. The application of temperature controlled X-ray diffraction (VTXRPD) to study the polymorphism of PMOL showed that the most stable form I (monoclinic) was altered to its less stable form II (orthorhombic) at high temperature (>112°C) in the binary blends regardless of the drug amount. Thus, VTXRD was used as a useful tool to monitor polymorphic transformations of crystalline drug (e.g. PMOL) to assess their thermal stability in terms of pharmaceutical product development and research.

  13. Study of LCP based flexible patch antenna array

    KAUST Repository

    Ghaffar, Farhan A.; Shamim, Atif; Roy, Langis

    2012-01-01

    Wrapping of a two element LCP based patch antenna array is studied in this work. For the first time, the designed array is bent in both E and H planes to observe the effect on the radiation and impedance performance of the antenna. The 38 GHz

  14. LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

    Science.gov (United States)

    Borden, C. S.

    1994-01-01

    The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site

  15. Diffusion of Lithium Ions in Amorphous and Crystalline Poly(ethylene oxide)_3:LiCF_3SO_3 Polymer Electrolytes

    International Nuclear Information System (INIS)

    Xue, Sha; Liu, Yingdi; Li, Yaping; Teeters, Dale; Crunkleton, Daniel W.; Wang, Sanwu

    2017-01-01

    The PEO_3:LiCF_3SO_3 polymer electrolyte has attracted significant research due to high conductivity and enhanced stability in lithium polymer batteries. Most experimental studies have shown that amorphous PEO lithium salt electrolytes have higher conductivity than the crystalline ones. Other studies, however, have shown that crystalline PEO salt complexes can conduct ions. As a result, further theoretical investigations are warranted to help clarify the issue. In this work, we use density functional theory with the climbing image nudged elastic band method to investigate the atomic-scale mechanism of lithium ion transport in the polymer electrolytes. We also use density functional theory and ab initio molecular dynamics simulations to obtain the amorphous structure of PEO_3:LiCF_3SO_3. The diffusion pathways and activation energies of lithium ions in both crystalline and amorphous PEO_3:LiCF_3SO_3 are determined. In crystalline PEO_3:LiCF_3SO_3, the activation energy for the low-barrier diffusion pathway is approximately 1.0 eV. In the amorphous phase, the value is 0.6 eV. This result would support the experimental observation that amorphous PEO_3:LiCF_3SO_3 has higher ionic conductivity than the crystalline phase.

  16. Synthesis of Isothianaphthene (ITN and 3,4-Ethylenedioxy-Thiophene (EDOT-Based Low-Bandgap Liquid Crystalline Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Hiromasa Goto

    2013-05-01

    Full Text Available Copolymers, consisting of isothianaphthene and phenylene derivatives with liquid crystal groups, were synthesized via Migita-Kosugi-Stille polycondensation reaction. IR absorption, UV-vis optical absorption, and PL spectroscopy measurements were carried out. Thermotropic liquid crystallinity of the polymers with bandgap of ~2.5 eV was confirmed.

  17. On the “Tertiary Structure” of Poly-Carbenes; Self-Assembly of sp3-Carbon-Based Polymers into Liquid-Crystalline Aggregates

    NARCIS (Netherlands)

    Franssen, N.G.M.; Ensing, B.; Hegde, M.; Dingemans, T.J.; Norder, B.; Picken, S.J.; Alberda van Ekenstein, G.O.R.; van Eck, E.R.H.; Elemans, J.A.A.W; Vis, M.; Reek, J.N.H.; de Bruin, B.

    2013-01-01

    The self-assembly of poly(ethylidene acetate) (st-PEA) into van der Waals-stabilized liquid-crystalline (LC) aggregates is reported. The LC behavior of these materials is unexpected, and unusual for flexible sp(3)-carbon backbone polymers. Although the dense packing of polar ester functionalities

  18. Calcium carbonate interaction analysis in polypropylene compounds and their impact on the formation of beta crystalline phase of this polymer

    International Nuclear Information System (INIS)

    Sakahara, Rogerio M.; Hui, Wang S.

    2011-01-01

    The insertion of calcium carbonate (CaCO 3 ) in polypropylene compound is a thoroughly known technique widely studied in the academic area and in the industry. Its wide application is due, mainly, to increase mechanical properties with low manufacturing cost. These improvements in this polymer make it more versatile and competitive compared to other expensive polymers. In this study, the incorporation of four types of CaCO3 from the same manufacturer were compared and the focus was on the size of this mineral filler. Furthermore, it was analyzed the interaction of graphitized polypropylene with maleic anhydride (PP-g-MA) in the same samples. All these samples were analyzed by WAXS and SEM. The physical properties of tensile strength and impact were also analyzed. It was observed from this study that the smallest CaCO3 produced with PP-g-MA resulted in better physical properties with the formation of a crystalline phase beta, as originally studied by other authors using other raw materials. (author)

  19. Stress controlled gas-barrier oxide coatings on semi-crystalline polymers

    International Nuclear Information System (INIS)

    Rochat, G.; Leterrier, Y.; Fayet, P.; Manson, J.-A.E.

    2005-01-01

    Thin silicon oxide (SiO x ) barrier coatings formed by plasma enhanced chemical vapor deposition on poly(ethylene terephthalate) (PET) substrates were subjected to post-deposition annealing treatments in the temperature range for orientation relaxation of the polymer. The resulting change in coating internal stress state was measured by means of thermo-mechanical analyses, and its effect on the coating cohesive properties and coating/polymer adhesion was determined from the analysis of uniaxial fragmentation tests in situ in a scanning electron microscope, assuming a Weibull-type probability of failure and a perfectly plastic stress transfer at the SiO x /PET interface. The strain to failure and intrinsic fracture toughness of the ultrathin oxide coating were found to be as high as 5.7% and 10 J/m 2 , respectively, and its interfacial shear strength with PET was found to be close to 100 MPa. Annealing for 10 min at 150 deg. C did not modify the oxygen permeation properties of the SiO x /PET film, which suggests that the defect population of the oxide was not affected by the thermal treatment. In contrast, the coating internal compressive stress resulting from annealing was shown to increase by 40% the apparent coating cohesive properties and adhesion to the polymer

  20. Effect of molecular structure and thermal treatment on photooptical properties of photochromic azobenzene-containing polymers films

    Czech Academy of Sciences Publication Activity Database

    Bobrovsky, A.; Shibaev, V.; Bubnov, Alexej; Hamplová, Věra; Kašpar, Miroslav; Pociecha, D.; Glogarová, Milada

    2011-01-01

    Roč. 212, č. 4 (2011), s. 342-352 ISSN 1022-1352 R&D Projects: GA AV ČR IAA100100911; GA AV ČR(CZ) GA202/09/0047; GA MŠk(CZ) OC10006 Grant - others:Federal Agency for Science and Innovation , Russian Federation(RU) RFASI No 02.740.11.5166 Institutional research plan: CEZ:AV0Z10100520 Keywords : calorimetry * liquid-crystalline polymers (LCP) * monomers phase behavior * polysiloxanes Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.361, year: 2011 http://onlinelibrary.wiley.com/doi/10.1002/macp.201000534/pdf

  1. Detection of gaseous effluents from partly crystalline polymer tubes for chemicals

    International Nuclear Information System (INIS)

    Hessel, J.; Henkhaus, R.; Buss, R.

    1980-01-01

    In case of polymer tubes which lead aggressive, liquid media and additionally have to sustain a mechanical load possibly at clevated temperatures a leakage can occur in the gas phase due to the permeability of the material. The paper describes a detection method for a quantitative analysis of the medium which desorbes on the outside of the tube wall. As examples the systems polypropylene/acetic acid and polyethylene/acetic acid were chosen. An inert carrier gas leads the desorbed medium to a conductivity cell which registers the conductivity as a function of time. The measured conductivity is directly proportional to the quantity of medium desorbed by the examined part of the tube. (orig.) [de

  2. Macromolecular crowding-assisted fabrication of liquid-crystalline imprinted polymers.

    Science.gov (United States)

    Zhang, Chen; Zhang, Jing; Huang, Yan-Ping; Liu, Zhao-Sheng

    2015-04-01

    A macromolecular crowding-assisted liquid-crystalline molecularly imprinted monolith (LC-MIM) was prepared successfully for the first time. The imprinted stationary phase was synthesized with polymethyl methacrylate (PMMA) or polystyrene (PS) as the crowding agent, 4-cyanophenyl dicyclohexyl propylene (CPCE) as the liquid-crystal monomer, and hydroquinidine as the pseudo-template for the chiral separation of cinchona alkaloids in HPLC. A low level of cross-linker (26%) has been found to be sufficient to achieve molecular recognition on the crowding-assisted LC-MIM due to the physical cross-linking of mesogenic groups in place of chemical cross-linking, and baseline separation of quinidine and quinine could be achieved with good resolution (R(s) = 2.96), selectivity factor (α = 2.16), and column efficiency (N = 2650 plates/m). In contrast, the LC-MIM prepared without crowding agents displayed the smallest diastereoselectivity (α = 1.90), while the crowding-assisted MIM with high level of cross-linker (80%) obtained the greatest selectivity factor (α = 7.65), but the lowest column efficiency (N = 177 plates/m).

  3. Enhanced drug delivery capabilities from stents coated with absorbable polymer and crystalline drug.

    Science.gov (United States)

    Carlyle, Wenda C; McClain, James B; Tzafriri, Abraham R; Bailey, Lynn; Zani, Brett G; Markham, Peter M; Stanley, James R L; Edelman, Elazer R

    2012-09-28

    Current drug eluting stent (DES) technology is not optimized with regard to the pharmacokinetics of drug delivery. A novel, absorbable-coating sirolimus-eluting stent (AC-SES) was evaluated for its capacity to deliver drug more evenly within the intimal area rather than concentrating drug around the stent struts and for its ability to match coating erosion with drug release. The coating consisted of absorbable poly-lactide-co-glycolic acid (PLGA) and crystalline sirolimus deposited by a dry-powder electrostatic process. The AC-SES demonstrated enhanced drug stability under simulated use conditions and consistent drug delivery balanced with coating erosion in a porcine coronary implant model. The initial drug burst was eliminated and drug release was sustained after implantation. The coating was absorbed within 90 days. Following implantation into porcine coronary arteries the AC-SES coating is distributed in the surrounding intimal tissue over the course of several weeks. Computational modeling of drug delivery characteristics demonstrates how distributed coating optimizes the load of drug immediately around each stent strut and extends drug delivery between stent struts. The result was a highly efficient arterial uptake of drug with superior performance to a clinical bare metal stent (BMS). Neointimal thickness (0.17±0.07 mm vs. 0.28±0.11 mm) and area percent stenosis (22±9% vs. 35±12%) were significantly reduced (pstent implantation in an overlap configuration in porcine coronary arteries. Inflammation was significantly reduced in the AC-SES compared to the BMS at both 30 and 90 days after implantation. Biocompatible, rapidly absorbable stent coatings enable the matching of drug release with coating erosion and provide for the controlled migration of coating material into tissue to reduce vicissitudes in drug tissue levels, optimizing efficacy and reducing potential toxicity. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Polymer Vesicles as Robust Scaffolds for the Directed Assembly of Highly Crystalline Nanocrystals †

    KAUST Repository

    Wang, Mingfeng

    2009-12-15

    We report the incorporation of various inorganic nanoparticles (NPs) (PbS, LaOF, LaF3, and TiO2, each capped by oleic acid, and CdSe/ZnS core/shell QDs capped by trioctylphosphine oxide) into vesicles (d = 70-150 nm) formed by a sample of poly(styrene-b-acrylic acid) (PS4o4-b-PAA 62, where the subscripts refer to the degree of polymerization) in mixtures of tetrahydrofuran (THF), dioxane, and water. The block copolymer formed mixtures of crew-cut micelles and vesicles with some enhancement of the vesicle population when the NPs were present. The vesicle fraction could be isolated by selective sedimentation via centrifugation, followed by redispersion in water. The NPs appeared to be incorporated into the PAA layers on the internal and external walls of the vesicles (strongly favoring the former). NPs on the exterior surface of the vesicles could be removed completely by treating the samples with a solution of ethylenediaminetetraacetate (EDTA) in water. The triangular nanoplatelets of LaF3 behaved differently. Stacks of these platelets were incorporated into solid colloidal entities, similar in size to the empty vesicles that accompanied them, during the coassembly as water was added to the polymer/LaF3/THF/ dioxane mixture. © 2009 American Chemical Society.

  5. Ericksen number and Deborah number cascade predictions of a model for liquid crystalline polymers for simple shear flow

    Science.gov (United States)

    Klein, D. Harley; Leal, L. Gary; García-Cervera, Carlos J.; Ceniceros, Hector D.

    2007-02-01

    We consider the behavior of the Doi-Marrucci-Greco (DMG) model for nematic liquid crystalline polymers in planar shear flow. We found the DMG model to exhibit dynamics in both qualitative and quantitative agreement with experimental observations reported by Larson and Mead [Liq. Cryst. 15, 151 (1993)] for the Ericksen number and Deborah number cascades. For increasing shear rates within the Ericksen number cascade, the DMG model displays three distinct regimes: stable simple shear, stable roll cells, and irregular structure accompanied by disclination formation. In accordance with experimental observations, the model predicts both ±1 and ±1/2 disclinations. Although ±1 defects form via the ridge-splitting mechanism first identified by Feng, Tao, and Leal [J. Fluid Mech. 449, 179 (2001)], a new mechanism is identified for the formation of ±1/2 defects. Within the Deborah number cascade, with increasing Deborah number, the DMG model exhibits a streamwise banded texture, in the absence of disclinations and roll cells, followed by a monodomain wherein the mean orientation lies within the shear plane throughout the domain.

  6. Formation process of hierarchical structures in crystalline polymers as analyzed by simultaneous measurements of small-angle X-ray scattering and other techniques

    International Nuclear Information System (INIS)

    Yamamoto, Katsuhiro; Sakurai, Shinichi

    2006-01-01

    Crystalline polymers spontaneously form hierarchical structures, which provide us a potential use as a specialty material. Recently, not only a crystalline homopolymer but also semi-crystalline block copolymers and crystalline polymer blends have been attracting interests for the study of a hierarchical structure. In order to analyze such hierarchical structures in a variety of length scales, a simultaneous measurement of small-(SAXS) and wide-angle (WAXS) X-ray scattering with differential scanning calorimetry (DSC), or with small-angle light scattering (Hv-SALS) are most suitable. In this review, we show some examples of the simultaneous measurements. With DSC, exothermic heat flow can be simultaneously measured with X-ray scattering. On the other hand, with Hv-SALS it is possible to analyze evolution of a spherulitic structure, which is the structure at the highest rank in the hierarchy. For both cases, one can realize that it is impossible to obtain good statistics for SAXS and WAXS measurements without synchrotron radiations. (author)

  7. Green Approach To Synthesize Crystalline Nanoscale ZnII-Coordination Polymers: Cell Growth Inhibition and Immunofluorescence Study.

    Science.gov (United States)

    Mukherjee, Somali; Ganguly, Sumi; Manna, Krishnendu; Mondal, Sanchaita; Mahapatra, Supratim; Das, Debasis

    2018-04-02

    Five new coordination polymers (CPs) namely, [{Zn(μ 2 -H 2 O) 0.5 (5N 3 -IPA)(2,2'-bpe)}] ∞ (1), [{Zn(μ 2 -H 2 O) 0.5 (5N 3 -IPA)(1,10-phen)}] ∞ (2), [{Zn(5N 3 -IPA)(1,2-bpe)}] ∞ (3), [{Zn(5N 3 -IPA)(1,2-bpey)}] ∞ (4), and [{Zn(H 2 O)(5N 3 -IPA)(4,4'-tme)}(H 2 O) 0.5 ] ∞ (5) (5N 3 -H 2 IPA = 5-azidoisophthalic acid, 2,2'-bpe= 2,2'-bipyridine, 1,10-phen = 1,10-phenanthroline, 1,2-bpe = 1,2-bis(4-pyridyl)ethane, 1,2-bpey = 1,2-bis(4-pyridyl)ethylene, 4,4'-tme = 4,4'-trimethylenedipyridine), have been synthesized based on a mixed ligand approach adopting a solvothermal technique. Depending upon the intrinsic structural flexibility of the bis-pyridyl coligands, interesting structural topologies have also been observed in the resulting CPs: Sra SrAl2 type topology for 3 and a 3-fold interpenetrated dmp topology for 4. A green hand grinding technique has been implemented to reduce the particle size of the CPs to generate nanoscale CPs (NCPs). SEM studies of NCPs reveal the formation of square and spherical particles for NCP 1 and 2, respectively, and nano rod for NCP 3, 4, and 5. Remarkably, when scaled down to nano range all the NCPs retain their crystalline nature. The cytotoxic activity of the NCPs (1-5) has been studied using human colorectal carcinoma cells (HCT 116). Significant cell death is observed for NCP 2, which is further corroborated by cell growth inhibition study. The observed cell death is likely to be due to mitochondrial-assisted apoptosis as is evident from immunofluorescence study.

  8. The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

    Energy Technology Data Exchange (ETDEWEB)

    Tylkowski, Bartosz; Castelao, Nuria [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Giamberini, Marta, E-mail: marta.giamberini@urv.net [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Garcia-Valls, Ricard [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain); Reina, Jose Antonio [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, Carrer Marcel.li Domingo s/n, E-43007, Tarragona (Spain); Gumi, Tania [Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Paiesos Catalans, 26, E-43007, Tarragona (Spain)

    2012-02-01

    We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion Registered-Sign N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH. - Highlights: Black-Right-Pointing-Pointer We prepared oriented membranes based on a liquid crystalline columnar polyether. Black-Right-Pointing-Pointer In this structure, the inner polyether chain could work as an ion channel. Black-Right-Pointing-Pointer We obtained membranes by casting a chloroform solution in the presence of water. Black-Right-Pointing-Pointer Membranes showed good proton permeability due to the presence of oriented channels.

  9. The importance of orientation in proton transport of a polymer film based on an oriented self-organized columnar liquid-crystalline polyether

    International Nuclear Information System (INIS)

    Tylkowski, Bartosz; Castelao, Nuria; Giamberini, Marta; Garcia-Valls, Ricard; Reina, José Antonio; Gumí, Tània

    2012-01-01

    We prepared membranes based on a liquid-crystalline side-chain polyether obtained by chemical modification of commercial poly(epichlorohydrin) (PECH) with dendrons. This polymer exhibited a columnar structure, which could form an ion channel in the inner part. The columns were successfully oriented by taking advantage of surface interactions between the polymer and hydrophilic substrates, as confirmed by X-ray diffraction analysis (XRD), environmental scanning electron microscopy (ESEM) and optical microscopy between crossed polars (POM). Column orientation was found to be crucial for effective transport: the oriented membranes exhibited proton transport comparable to that of Nafion® N117 and no water uptake. An increase in sodium ion concentration in the feed phase suggested a proton/cation antiport. On the contrary, no proton transport was detected on unoriented membranes based on the same liquid-crystalline side-chain polyether or on unmodified PECH. - Highlights: ► We prepared oriented membranes based on a liquid crystalline columnar polyether. ► In this structure, the inner polyether chain could work as an ion channel. ► We obtained membranes by casting a chloroform solution in the presence of water. ► Membranes showed good proton permeability due to the presence of oriented channels.

  10. Pathogenic Leptospira species acquire factor H and vitronectin via the surface protein LcpA.

    Science.gov (United States)

    da Silva, Ludmila Bezerra; Miragaia, Lidia Dos Santos; Breda, Leandro Carvalho Dantas; Abe, Cecilia Mari; Schmidt, Mariana Costa Braga; Moro, Ana Maria; Monaris, Denize; Conde, Jonas Nascimento; Józsi, Mihály; Isaac, Lourdes; Abreu, Patrícia Antônia Estima; Barbosa, Angela Silva

    2015-03-01

    Upon infection, pathogenic Leptospira species bind several complement regulators in order to overcome host innate immunity. We previously characterized a 20-kDa leptospiral surface protein which interacts with C4b binding protein (C4BP): leptospiral complement regulator-acquiring protein A (LcpA). Here we show that LcpA also interacts with human factor H (FH), which remains functionally active once bound to the protein. Antibodies directed against short consensus repeat 20 (SCR20) inhibited binding of FH to LcpA by approximately 90%, thus confirming that this particular domain is involved in the interaction. We have also shown for the first time that leptospires bind human vitronectin and that the interaction is mediated by LcpA. Coincubation with heparin blocked LcpA-vitronectin interaction in a dose-dependent manner, strongly suggesting that binding may occur through the heparin binding domains of vitronectin. LcpA also bound to the terminal pathway component C9 and inhibited Zn(2+)-induced polymerization and membrane attack complex (MAC) formation. Competitive binding assays indicated that LcpA interacts with C4BP, FH, and vitronectin through distinct sites. Taken together, our findings indicate that LcpA may play a role in leptospiral immune evasion. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  11. Histidine at Position 195 is Essential for Association of Heme- b in Lcp1VH2

    Science.gov (United States)

    Oetermann, Sylvia; Vivod, Robin; Hiessl, Sebastian; Hogeback, Jens; Holtkamp, Michael; Karst, Uwe; Steinbüchel, Alexander

    2018-05-01

    The latex clearing protein (Lcp) is the key enzyme of polyisoprene degradation in actinomycetes (Yikmis and Steinbüchel in Appl Environ Microbiol 78:4543-4551, https://doi.org/10.1128/AEM.00001-12 , 2012). In this study it was shown that Lcp from Gordonia polyisoprenivorans VH2 (Lcp1VH2) harbors a non-covalently bound heme b as cofactor, which was identified by pyridine hemochrome spectra and confirmed by LC/ESI-ToF-MS. It contains iron, most likely in the Fe3+ state. We focused on the characterization of the heme-cofactor, its accessibility with respect to the conformation of Lcp1VH2, and the identification of putative histidine residues involved in the coordination of heme. A change was detectable in UV/Vis-spectra of reduced Lcp1VH2 when imidazole was added, showing that Lcp1VH2 "as isolated" occurs in an open state, directly being accessible for external ligands. In addition, three highly conserved histidines (H195, H200 and H228), presumably acting as ligands coordinating the heme within the heme pocket, were replaced with alanines by site-directed mutagenesis. The effect of these changes on in vivo rubber-mineralization was investigated. The lcp- deletion mutant complemented with the H195A variant of lcp1 VH2 was unable to mineralize poly( cis-1,4-isoprene). In vitro analyses of purified, recombinant Lcp1VH2H195A confirmed the loss of enzyme activity, which could be ascribed to the loss of heme. Hence, H195 is essential for the association of heme- b in the central region of Lcp1VH2.

  12. A PROSPECTIVE STUDY OF DISTAL TIBIAL FRACTURES BY MIPO (LCP

    Directory of Open Access Journals (Sweden)

    Chandra Sekharam Naidu

    2015-05-01

    contact . 9 MIPO promoted by AO group emphasis on indirect reduction, axial alignment and s table fixation without disturbing the fracture environment and thus preserving most of the vascularization and fracture haematoma, containing all necessary growth factors for bony healing. Technique of closed reduction and MIPPO with LCP has emerged as an alternative treatment option for distal dia - metaphyseal tibia fracture. When applied subcutaneously, LCP does not endanger periosteal blood supply, respect fracture heamtoma and also provides biomechanically stable construct. Several clinical studies have established MIPO with LCP as a biologically friendly and technically sound method of fixation for distal meta - diaphyseal tibial fracture.

  13. Biomass enzymatic saccharification is determined by the non-KOH-extractable wall polymer features that predominately affect cellulose crystallinity in corn.

    Science.gov (United States)

    Jia, Jun; Yu, Bin; Wu, Leiming; Wang, Hongwu; Wu, Zhiliang; Li, Ming; Huang, Pengyan; Feng, Shengqiu; Chen, Peng; Zheng, Yonglian; Peng, Liangcai

    2014-01-01

    Corn is a major food crop with enormous biomass residues for biofuel production. Due to cell wall recalcitrance, it becomes essential to identify the key factors of lignocellulose on biomass saccharification. In this study, we examined total 40 corn accessions that displayed a diverse cell wall composition. Correlation analysis showed that cellulose and lignin levels negatively affected biomass digestibility after NaOH pretreatments at pcorn samples indicated that cellulose and lignin should not be the major factors on biomass saccharification after pretreatments with NaOH and H2SO4 at three concentrations. Notably, despite that the non-KOH-extractable residues covered 12%-23% hemicelluloses and lignin of total biomass, their wall polymer features exhibited the predominant effects on biomass enzymatic hydrolysis including Ara substitution degree of xylan (reverse Xyl/Ara) and S/G ratio of lignin. Furthermore, the non-KOH-extractable polymer features could significantly affect lignocellulose crystallinity at pcorn.

  14. Study of LCP based flexible patch antenna array

    KAUST Repository

    Ghaffar, Farhan A.

    2012-07-01

    Wrapping of a two element LCP based patch antenna array is studied in this work. For the first time, the designed array is bent in both E and H planes to observe the effect on the radiation and impedance performance of the antenna. The 38 GHz simulation results reveal better performance for H plane bending as compared to E plane bending. A 100 um thick substrate is used for the design which is best suited for flexible antenna applications. Gain variations of 1.1 dB and 1.4 dB are observed for the two orientations while a significantly increased impedance bandwidth of 3 % is obtained with H plane wrapping. The design is highly suitable for broadband micro-cellular backhaul applications. © 2012 IEEE.

  15. Molecular Design for Preparation of Hexagonal-Ordered Porous Films Based on Side-chain Type Liquid-Crystalline Star Polymer.

    Science.gov (United States)

    Naka, Yumiko; Takayama, Hiromu; Koyama, Teruhisa; Le, Khoa V; Sasaki, Takeo

    2018-05-02

    Fabrication of regularly porous films by the breath-figure method has attracted much attention. The simple, low-cost technique uses the condensation of water droplets to produce these structures, but the phenomenon itself is complex, requiring control over many interacting parameters that change throughout the process. Developing a unified understanding for the molecular design of polymers to prepare ordered porous films is challenging, but required for further advancements. In this article, the effects of the chemical structure of polymers in the breath-figure technique were systematically explored using side-chain type liquid-crystalline (LC) star polymers. The formation of porous films was affected by the structure of the polymers. Although the entire film surface of poly(11-[4-(4-cyanobiphenyl)oxy]undecyl methacrylate) (P11CB) had a hexagonal ordered porous structure over a certain Mn value, regularly arranged holes did not easily form in poly(methyl methacrylate) (PMMA), even though the main chain of PMMA is similar to that of P11CB. Comparing P11CB and poly(11-[(1,1'-biphenyl)-4-yloxy]undecyl methacrylate) (P11B) (P11CB without cyano groups) showed that the local polar groups in hydrophobic polymers promoted the formation of ordered porous films. No holes formed in poly(4-cyanobiphenyl methacrylate) (P0CB) (P11CB without alkyl spacers) films due to its hydrophilicity. The introduction of alkyl chains in P0CB allowed the preparation of honeycomb-structured films by increasing the internal tension. However, alkyl chains in the side chain alone did not result in a porous structure, as in the case of poly(11-[(1,1'-biphenyl)-4-yloxy]undecyl methacrylate) (P11). Aromatic rings are also required to increase the Tg and improve film formability. In the present study, suitable molecular designs of polymers were found, specifically hydrophobic polymers with local polar groups, to form a regularly porous structure. Development of clear guidelines for the molecular

  16. PVD Silicon Carbide as a Thin Film Packaging Technology for Antennas on LCP Substrates for Harsh Environments

    Science.gov (United States)

    Scardelletti, Maximilian C.; Stanton, John W.; Ponchak, George E.; Jordan, Jennifer L.; Zorman, Christian A.

    2010-01-01

    This paper describes an effort to develop a thin film packaging technology for microfabricated planar antennas on polymeric substrates based on silicon carbide (SiC) films deposited by physical vapor deposition (PVD). The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on liquid crystal polymer (LCP) substrates. The PVD SiC thin films were deposited directly onto the antennas by RF sputtering at room temperature at a chamber pressure of 30 mTorr and a power level of 300 W. The SiC film thickness is 450 nm. The return loss and radiation patterns were measured before and after the SiC-coated antennas were submerged into perchloric acid for 1 hour. No degradation in RF performance or physical integrity of the antenna was observed.

  17. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui; Yu, Xinhong; Li, Ruipeng; Amassian, Aram; Han, Yanchun

    2015-01-01

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport

  18. Carbon/Liquid Crystal Polymer Prepreg for Cryogenic and High-Temp Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — KaZaK Composites proposes to develop a pultrusion process to produce carbon fiber / liquid crystal polymer (LCP) prepreg, a first for this category of materials and...

  19. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui

    2015-09-07

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport and optoelectronic properties. Yet, to date the vast majority of studies have focused on the fast solution process itself, with studies of slower intrinsic molecular self-assembly in formulations lagging behind. Here we have investigated molecular self-assembly during spontaneous organization and uncovered how changes in formulation influence the microstructure, morphology and transport properties of conjugated polymer thin films. Our results suggest that the polymer-solvent interaction is the key factor for the molecular self-assembly and changes in macroscopic charge transport, which is in contrast with most solution processes, such as spin-coating and blade coating, where solvent drying kinetics dominates the aggregation and crystallization processes. Energetically favourable interactions between the polymer and its solvent are shown to cause chain expansion, resulting in a large hydrodynamic volume and few chain entanglements in solution. This provides molecular freedom for self-assembly and is shown to greatly enhance the local and long range order of the polymer, intra-chain backbone planarity and crystallite size. These improvements, in turn, are shown to endow the conjugated polymer with high carrier transport, as demonstrated by organic thin film transistors.

  20. [Comparison of LCP and locked intramedullary nailing fixation in treatment of tibial diaphysis fractures].

    Science.gov (United States)

    Huang, Peng; Tang, Peifu; Yao, Qi

    2007-11-01

    To evaluate the treatment results of LCP and locked intramedullary nailing for tibial diaphysis fractures. From October 2003 to April 2006, 55 patients with tibial diaphysis fractures (58 fractures) were treated. Of them there were 39 males and 16 females with an average of 39 years years ( 14 to 62 years). The fractures were on the left side in 27 patients and on the right side in 31 patients (3 patients had bilateral involvement). Thirty-four fractures were treated by intramedullary nailing (intramedullary nailing group) and 24 fractures by LCP fixation (LCP group). The average disease course was 3 days (intramedullary nailing group) and 3.1 days (LCP group). The operation time, the range of motion of knee and ankle joints, fracture healing time, and complications were evaluated. The patients were followed up 8-26 months (13 months on average). The operation time was 84.0+/-9.2 min (intramedullary nailing group) and 69.0+/-8.4 min (LCP group); the average cost in hospital was yen 19,297.78 in the intramedullary nailing group and yen 14,116.55 in the LCP group respectively, showing significant differences (P 0.05). The doral flexion and plantar flexion of ankle joint were 13.0+/-1.7 degrees and 41.0+/-2.6 degrees in intramedullary nailing group, and 10.0+/-1.4 degrees and 44.0+/-2.3 degrees in LCP group, showing no significant differences (P>0.05). The mean healing time was 3.3 months in intramedullary nailing group, and 3. 1 months in LCP group. Length discrepancy occurred in 1 case (2.5 cm), delayed union in 1 case and nailing end trouble in 3 cases in intramedullary nailing group; moreover rotation deformity occurred 1 case and anterior knee pain occurred in 6 cases (17.1%). One angulation and open fracture developed osteomyelitis in 1 case 1 week postoperatively and angulation deformity occurred in 1 case of distal-third tibial fractures in LCP group. LCP and locked intramedullary nailing can achieve satisfactory results in treating tibial diaphysis fracture

  1. Coupled effects of director orientations and boundary conditions on light induced bending of monodomain nematic liquid crystalline polymer plates

    International Nuclear Information System (INIS)

    You, Yue; Ding, Shurong; Huo, Yongzhong; Xu, Changwei

    2012-01-01

    A photo-chromic liquid crystal polymers (LCPs) is a smart material for large light-activated variation or bending to transfer luminous energy into mechanical energy. We study the light induced behavior by modeling planar and homeotropic nematic network polymer plates. We effectively illustrate some reported experimental outcomes and theoretically predict some possible bending patterns. This paper constructs an understanding between the bending behaviors and interactions among the alignments, aspect ratios and boundary conditions, etc. Our work provides information on optimizing light induced bending in the process of micro-opto-mechanical system (MOMS) design. (paper)

  2. Biomass enzymatic saccharification is determined by the non-KOH-extractable wall polymer features that predominately affect cellulose crystallinity in corn.

    Directory of Open Access Journals (Sweden)

    Jun Jia

    Full Text Available Corn is a major food crop with enormous biomass residues for biofuel production. Due to cell wall recalcitrance, it becomes essential to identify the key factors of lignocellulose on biomass saccharification. In this study, we examined total 40 corn accessions that displayed a diverse cell wall composition. Correlation analysis showed that cellulose and lignin levels negatively affected biomass digestibility after NaOH pretreatments at p<0.05 & 0.01, but hemicelluloses did not show any significant impact on hexoses yields. Comparative analysis of five standard pairs of corn samples indicated that cellulose and lignin should not be the major factors on biomass saccharification after pretreatments with NaOH and H2SO4 at three concentrations. Notably, despite that the non-KOH-extractable residues covered 12%-23% hemicelluloses and lignin of total biomass, their wall polymer features exhibited the predominant effects on biomass enzymatic hydrolysis including Ara substitution degree of xylan (reverse Xyl/Ara and S/G ratio of lignin. Furthermore, the non-KOH-extractable polymer features could significantly affect lignocellulose crystallinity at p<0.05, leading to a high biomass digestibility. Hence, this study could suggest an optimal approach for genetic modification of plant cell walls in bioenergy corn.

  3. Biomass Enzymatic Saccharification Is Determined by the Non-KOH-Extractable Wall Polymer Features That Predominately Affect Cellulose Crystallinity in Corn

    Science.gov (United States)

    Wu, Leiming; Wang, Hongwu; Wu, Zhiliang; Li, Ming; Huang, Pengyan; Feng, Shengqiu; Chen, Peng; Zheng, Yonglian; Peng, Liangcai

    2014-01-01

    Corn is a major food crop with enormous biomass residues for biofuel production. Due to cell wall recalcitrance, it becomes essential to identify the key factors of lignocellulose on biomass saccharification. In this study, we examined total 40 corn accessions that displayed a diverse cell wall composition. Correlation analysis showed that cellulose and lignin levels negatively affected biomass digestibility after NaOH pretreatments at pbiomass saccharification after pretreatments with NaOH and H2SO4 at three concentrations. Notably, despite that the non-KOH-extractable residues covered 12%–23% hemicelluloses and lignin of total biomass, their wall polymer features exhibited the predominant effects on biomass enzymatic hydrolysis including Ara substitution degree of xylan (reverse Xyl/Ara) and S/G ratio of lignin. Furthermore, the non-KOH-extractable polymer features could significantly affect lignocellulose crystallinity at pbiomass digestibility. Hence, this study could suggest an optimal approach for genetic modification of plant cell walls in bioenergy corn. PMID:25251456

  4. Semiflexible polymers confined in a slit pore with attractive walls: two-dimensional liquid crystalline order versus capillary nematization.

    Science.gov (United States)

    Milchev, Andrey; Egorov, Sergei A; Binder, Kurt

    2017-03-01

    Semiflexible polymers under good solvent conditions interacting with attractive planar surfaces are investigated by Molecular Dynamics (MD) simulations and classical Density Functional Theory (DFT). A bead-spring type potential complemented by a bending potential is used, allowing variation of chain stiffness from completely flexible coils to rod-like polymers whose persistence length by far exceeds their contour length. Solvent is only implicitly included, monomer-monomer interactions being purely repulsive, while two types of attractive wall-monomer interactions are considered: (i) a strongly attractive Mie-type potential, appropriate for a strictly structureless wall, and (ii) a corrugated wall formed by Lennard-Jones particles arranged on a square lattice. It is found that in dilute solutions the former case leads to the formation of a strongly adsorbed surface layer, and the profile of density and orientational order in the z-direction perpendicular to the wall is predicted by DFT in nice agreement with MD. While for very low bulk densities a Kosterlitz-Thouless type transition from the isotropic phase to a phase with power-law decay of nematic correlations is suggested to occur in the strongly adsorbed layer, for larger densities a smectic-C phase in the surface layer is detected. No "capillary nematization" effect at higher bulk densities is found in this system, unlike systems with repulsive walls. This finding is attributed to the reduction of the bulk density (in the center of the slit pore) due to polymer adsorption on the attractive wall, for a system studied in the canonical ensemble. Consequently in a system with two attractive walls nematic order in the slit pore can occur only at a higher density than for a bulk system.

  5. Introduction of chemical, physical and mechanical coupling in the study of the blistering phenomena for semi-crystalline polymers; Une approche multiphysique de l'endommagement de polymeres en milieu petrolier: exemple du blistering

    Energy Technology Data Exchange (ETDEWEB)

    Cangemi, L.; Klopffer, M.H.; Martin, J. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France); Grandidier, J.C. [Poitiers Univ., Lab. de Mecanique et de Physique des Materiaux, UMR 6617 CNRS, ENSMA, 86 (France)

    2005-09-01

    Polymer materials are used in numerous oil applications where the knowledge and the control of their barrier properties are required: thermosetting coatings, rubber seals, thermoplastic liners. In that case, thermoplastic materials are in contact with water, hydrocarbons, gases and all carried fluids at high temperature and high pressure (up to 13 deg C and to 100 MPa). Under these extreme conditions, gases contained in petroleum products (such as H{sub 2}S, CO{sub 2}) have a high tendency to dissolve into semi-crystalline polymers (polyolefins, fluorinated polymers). A decompression, i.e. a rupture of the thermodynamic equilibrium may eventually lead to gas concentration and temperature gradients in the polymer structures. The resulting damaging phenomenon is called blistering and can be really dramatic for the material because it is irreversible and may end the pipe leak-proofness. As a matter of fact, the condition of damage is mainly correlated to the temperature, the rate of decompression and the properties of the material. Thereby, it is important to have an accurate knowledge of all the involved phenomena in order to quantify and then predict the barrier properties of the materials in those aggressive conditions. The aim of this study is to identify the various mechanism involved in the blistering phenomena for semi-crystalline polymers (such as PVF2, PE), to establish some relations between the polymer microstructure (morphology), its mechanical properties and the damage and to build physicochemical models which will take into account some mechanical, thermal and diffusional aspects. (authors)

  6. Concentrator bifacial crystalline silicon solar cells with multi-wire metallization attached to TCO layers using transparent conductive polymers

    Science.gov (United States)

    Untila, Gennady; Chebotareva, Alla; Kost, Tatiana; Salazkin, Sergei; Shaposhnikova, Vera; Shvarts, Maxim

    2017-09-01

    Replacing expensive silver with inexpensive copper for the metallization of silicon wafer solar cells can lead to substantial reductions in material costs associated with cell production. A promising approach is the use of multi-wire design. This technology uses many wires in the place of busbars, and the copper wires are "soldered" during the low-temperature lamination process to the fingers (printed or plated) or to the transparent conductive oxide (TCO) layer, e.g. in the case of the α-Si/c-Si heterojunction cells. Here we describe a solar cell design in which wires are attached to TCO layers using transparent conductive polymer (TCP) films. To this end, we have synthesized a number of thermoplastics, poly(arylene ether ketone) copolymers (co-PAEKs), containing phthalide in their main chain. The fraction of phthalide-containing units in the copolymers was p = 3, 5, 15, and 50 mol %. With increasing p, the peak strain temperature of the co-PAEKs rises from 205 to 290 °C and their optical band gap and refractive index increase from 3.12 to 3.15 eV and from 1.6 to 1.614, respectively. The copolymers have a negligible absorption coefficient in the wavelength range 400- 1100 nm. When exposed to an excess pressure of 1 atm or above, co-PAEK films less than 30 µm in thickness undergo a transition from a dielectric to a conductive state. The resistivity (ρC) of wire/TCP/TCO (ITO = In2O3:Sn and IFO = In2O3:F) contacts ranges from 0.37 to 1.43 mΩ cm2. The polymer with the highest phthalide content (p = 50 mol %) has the lowest ρC. The average work of adhesion per unit area determined by pulling off the wires from the polymer surface depends on both the phthalide content of the co-PAEKs and their reduced viscosity, ranging from 14.3 to 43.5 N/cm. The highest value was obtained for the co-PAEK with p = 50 mol %. We have fabricated low-concentration bifacial IFO/(n+pp+)Cz-Si/ITO solar cells with a wire contact grid attached to IFO and ITO using a co-PAEK film. The

  7. Competitive concurrence of surface wrinkling and dewetting of liquid crystalline polymer films on non-wettable substrates.

    Science.gov (United States)

    Song, Sung E; Choi, Gwan H; Yi, Gi-Ra; Yoo, Pil J

    2017-11-01

    Polymeric thin films coated on non-wettable substrates undergo film-instabilities, which are usually manifested as surface deformation in the form of dewetting or wrinkling. The former takes place in fluidic films, whereas the latter occurs in solid films. Therefore, there have rarely been reports of systems involving simultaneous deformations of dewetting and wrinkling. In this study, we propose polymeric thin films of liquid crystalline (LC) mesogens prepared on a non-wettable Si substrate and apply a treatment of plasma irradiation to form a thin polymerized layer at the surface. The resulting compressive stress generated in the surface region drives the formation of wrinkles, while at the same time, dipolar attraction between LC molecules induces competitive cohesive dewetting. Intriguing surface structures were obtained whereby dewetting-like hole arrays are nested inside the randomly propagated wrinkles. The structural features are readily controlled by the degree of surface cross-linking, hydrophilicity of the substrates, and the LC film thickness. In particular, dewetting of LC mesogens is observed to be restricted to occur at the trough regions of wrinkles, exhibiting the typical behavior of geometrically confined dewetting. Finally, wrinkling-dewetting mixed structures are separated from the substrate in the form of free standing films to demonstrate the potential applicability as membranes.

  8. Comparison of the Resistance to Bending Forces of the 4.5 LCP Plate-rod Construct and of 4.5 LCP Alone Applied to Segmental Femoral Defects in Miniature Pigs

    Directory of Open Access Journals (Sweden)

    Lucie Urbanová

    2010-01-01

    Full Text Available The study deals with the determination of mechanical properties, namely resistance to bending forces, of flexible buttress osteosynthesis using two different bone-implant constructs stabilizing experimental segmental femoral bone defects (segmental ostectomy in a miniature pig ex vivo model using 4.5 mm titanium LCP and a 3 mm intramedullary pin (“plate and rod” construct (PR-LCP, versus the 4.5 mm titanium LCP alone (A-LCP. The “plate and rod” fixation (PR-LCP of the segmental femoral defect is significantly more resistant (p in vivo experiments in the miniature pig to investigate bone defect healing after transplantation of mesenchymal stem cells in combination with biocompatible scaffolds.

  9. Histidine at Position 195 is Essential for Association of Heme-b in Lcp1VH2

    Science.gov (United States)

    Oetermann, Sylvia; Vivod, Robin; Hiessl, Sebastian; Hogeback, Jens; Holtkamp, Michael; Karst, Uwe; Steinbüchel, Alexander

    2018-03-01

    The latex clearing protein (Lcp) is the key enzyme of polyisoprene degradation in actinomycetes (Yikmis and Steinbüchel in Appl Environ Microbiol 78:4543-4551, https://doi.org/10.1128/AEM.00001-12, 2012). In this study it was shown that Lcp from Gordonia polyisoprenivorans VH2 (Lcp1VH2) harbors a non-covalently bound heme b as cofactor, which was identified by pyridine hemochrome spectra and confirmed by LC/ESI-ToF-MS. It contains iron, most likely in the Fe3+ state. We focused on the characterization of the heme-cofactor, its accessibility with respect to the conformation of Lcp1VH2, and the identification of putative histidine residues involved in the coordination of heme. A change was detectable in UV/Vis-spectra of reduced Lcp1VH2 when imidazole was added, showing that Lcp1VH2 "as isolated" occurs in an open state, directly being accessible for external ligands. In addition, three highly conserved histidines (H195, H200 and H228), presumably acting as ligands coordinating the heme within the heme pocket, were replaced with alanines by site-directed mutagenesis. The effect of these changes on in vivo rubber-mineralization was investigated. The lcp- deletion mutant complemented with the H195A variant of lcp1 VH2 was unable to mineralize poly(cis-1,4-isoprene). In vitro analyses of purified, recombinant Lcp1VH2H195A confirmed the loss of enzyme activity, which could be ascribed to the loss of heme. Hence, H195 is essential for the association of heme-b in the central region of Lcp1VH2.

  10. Users Manual for the Program LCP2 (Version 2.40)

    DEFF Research Database (Denmark)

    Gaunholt, Hans

    1996-01-01

    LCP2 (Linear Circuit Program) is developed as an analysis and optimization tool to be used in the design of passive, active and digital filters with arbitrary structures. By the aid of an optimization loop the program may be used to solve nonlinear design equations for active filter structures or...

  11. CO2 Sparging Proof of Concept Test Report, Revision 1, LCP Chemicals Site, Brunswick, Georgia

    Science.gov (United States)

    April 2013 report to evaluate the feasibility of CO2 sparging to remediate a sub-surface caustic brine pool (CBP) at the LCP Chemicals Superfund Site, GA. Region ID : 04, DocID: 10940639 , DocDate: 2013-04-01

  12. A fast Linear Complementarity Problem (LCP) solver for separating fluid-solid wall boundary Conditions

    DEFF Research Database (Denmark)

    Andersen, Michael; Abel, Sarah Maria Niebe; Erleben, Kenny

    2017-01-01

    We address the task of computing solutions for a separating fluid-solid wall boundary condition model. We present an embarrassingly parallel, easy to implement, fluid LCP solver.We are able to use greater domain sizes than previous works have shown, due to our new solver. The solver exploits matr...

  13. Miniaturized and Ferrite Based Tunable Bandpass Filters in LCP and LTCC Technologies for SoP Applications

    KAUST Repository

    Arabi, Eyad A.

    2015-04-01

    Wireless systems with emerging applications are leaning towards small size, light-weight and low cost. Another trend for these wireless devices is that new applications and functionalities are being added without increasing the size of the device. To accomplish this, individual components must be miniaturized and the system should be designed to maximize the integration of the individual components. The high level of 3D integration feasible in system on package design (SoP) concept can fulfill the latter requirement. Bandpass filters are important components on all wireless systems to reject the unwanted signals and reduce interference. Being mostly implemented with passive and distributed components, bandpass filters take considerable space in a wireless system. Moreover, with emerging bands and multiple applications encompassed in a single device, many bandpass filters are required. The miniaturization related to bandpass filters can be approached by three main ways: (1) at the component level through the miniaturization of individual bandpass filters, (2) at the system level through the use of tunable filters to reduce the overall number of filters, and (3) at the system level through the high level of integration in a 3D SoP platform. In this work we have focused on all three aspects of miniaturization of band pass filters mentioned above. In the first part of this work, a low frequency (1.5 GHz global positioning system (GPS) band) filter implemented through 3D lumped components in two leading SoP technologies, namely low temperature co-fired ceramic (LTCC) and the liquid crystal polymers (LCP) is demonstrated. The miniaturized filter is based on a second order topology, which has been modified to improve the selectivity and out-of-band rejection without increasing the size. Moreover, for the case of LCP, the filter is realized in an ultra-thin stack up comprising four metallization layers with an overall thickness of only 100 _m. Due to its ultra

  14. 3D lumped components and miniaturized bandpass filter in an ultra-thin M-LCP for SOP applications

    KAUST Repository

    Arabi, Eyad A.

    2013-01-01

    In this work, a library of 3D lumped components completely embedded in the thinnest, multilayer LCP (M-LCP) stack- up with four metallization layers and 100 μm of total thickness, is reported for the first time. A vertically and horizontally interdigitated capacitor, realized in this stack-up, provides higher self resonant frequency as compared to a similarly sized conventional parallel plate capacitor. Based on the above mentioned library, a miniaturized bandpass filter is presented for the GPS application. It utilizes mutually coupled inductors and is the smallest reported in the literature with a size of (0.035×0.028×0.00089)λg. Finally, the same filter realized in a competing ceramic technology (LTCC) is compared in performance with the ultra-thin M-LCP design. The M-LCP module presented in this work is inherently exible and offers great potential for wearable and conformal applications.

  15. Potential of a newly developed high-speed near-infrared (NIR) camera (Compovision) in polymer industrial analyses: monitoring crystallinity and crystal evolution of polylactic acid (PLA) and concentration of PLA in PLA/Poly-(R)-3-hydroxybutyrate (PHB) blends.

    Science.gov (United States)

    Ishikawa, Daitaro; Nishii, Takashi; Mizuno, Fumiaki; Sato, Harumi; Kazarian, Sergei G; Ozaki, Yukihiro

    2013-12-01

    This study was carried out to evaluate a new high-speed hyperspectral near-infrared (NIR) camera named Compovision. Quantitative analyses of the crystallinity and crystal evolution of biodegradable polymer, polylactic acid (PLA), and its concentration in PLA/poly-(R)-3-hydroxybutyrate (PHB) blends were investigated using near-infrared (NIR) imaging. This NIR camera can measure two-dimensional NIR spectral data in the 1000-2350 nm region obtaining images with wide field of view of 150 × 250 mm(2) (approximately 100  000 pixels) at high speeds (in less than 5 s). PLA with differing crystallinities between 0 and 50% blended samples with PHB in ratios of 80/20, 60/40, 40/60, 20/80, and pure films of 100% PLA and PHB were prepared. Compovision was used to collect respective NIR spectra in the 1000-2350 nm region and investigate the crystallinity of PLA and its concentration in the blends. The partial least squares (PLS) regression models for the crystallinity of PLA were developed using absorbance, second derivative, and standard normal variate (SNV) spectra from the most informative region of the spectra, between 1600 and 2000 nm. The predicted results of PLS models achieved using the absorbance and second derivative spectra were fairly good with a root mean square error (RMSE) of less than 6.1% and a determination of coefficient (R(2)) of more than 0.88 for PLS factor 1. The results obtained using the SNV spectra yielded the best prediction with the smallest RMSE of 2.93% and the highest R(2) of 0.976. Moreover, PLS models developed for estimating the concentration of PLA in the blend polymers using SNV spectra gave good predicted results where the RMSE was 4.94% and R(2) was 0.98. The SNV-based models provided the best-predicted results, since it can reduce the effects of the spectral changes induced by the inhomogeneity and the thickness of the samples. Wide area crystal evolution of PLA on a plate where a temperature slope of 70-105 °C had occurred was also

  16. LCP method for a planar passive dynamic walker based on an event-driven scheme

    Science.gov (United States)

    Zheng, Xu-Dong; Wang, Qi

    2018-06-01

    The main purpose of this paper is to present a linear complementarity problem (LCP) method for a planar passive dynamic walker with round feet based on an event-driven scheme. The passive dynamic walker is treated as a planar multi-rigid-body system. The dynamic equations of the passive dynamic walker are obtained by using Lagrange's equations of the second kind. The normal forces and frictional forces acting on the feet of the passive walker are described based on a modified Hertz contact model and Coulomb's law of dry friction. The state transition problem of stick-slip between feet and floor is formulated as an LCP, which is solved with an event-driven scheme. Finally, to validate the methodology, four gaits of the walker are simulated: the stance leg neither slips nor bounces; the stance leg slips without bouncing; the stance leg bounces without slipping; the walker stands after walking several steps.

  17. A copper-based layered coordination polymer: synthesis, magnetic properties and electrochemical performance in supercapacitors.

    Science.gov (United States)

    Liu, Qi; Liu, Xiuxiu; Shi, Changdong; Zhang, Yanpeng; Feng, Xuejun; Cheng, Mei-Ling; Su, Seng; Gu, Jiande

    2015-11-28

    A copper-based layered coordination polymer ([Cu(hmt)(tfbdc)(H2O)]; hmt = hexamethylenetetramine, tfbdc = 2,3,5,6-tetrafluoroterephthalate; Cu-LCP) has been synthesized, and it has been structurally and magnetically characterized. The Cu-LCP shows ferromagnetic interactions between the adjacent copper(II) ions. Density functional theory calculations on the special model of Cu-LCP support the occurrence of ferromagnetic interactions. As an electrode material for supercapacitors, Cu-LCP exhibits a high specific capacitance of 1274 F g(-1) at a current density of 1 A g(-1) in 1 M LiOH electrolyte, and the capacitance retention is about 88% after 2000 cycles.

  18. Treatment of type 2 and 4 olecranon fractures with locking compression plate (LCP) osteosynthesis in horses: a prospective study (2002-2008)

    OpenAIRE

    Jackson, M; Kummer, M; Auer, J; Hagen, R; Fürst, A

    2011-01-01

    This prospective study describes a series of 18 olecranon fractures in 16 horses that were treated with locking compression plates (LCP). Twelve of the 18 fractures were simple (type 2), whereas six were comminuted (type 4). Six fractures were open and 12 were closed. Each horse underwent LCP osteosynthesis consisting of open reduction and application of one or two LCP. Complete fracture healing was achieved in 13 horses. Three horses had to be euthanatized: two because of severe infection an...

  19. Mathematical model of mechanical testing of bone-implant (4.5 mm LCP construct

    Directory of Open Access Journals (Sweden)

    Lucie Urbanová

    2012-01-01

    Full Text Available The study deals with the possibility of substituting time- and material-demanding mechanical testing of a bone defect fixation by mathematical modelling. Based on the mechanical model, a mathematical model of bone-implant construct stabilizing experimental segmental femoral bone defect (segmental ostectomy in a miniature pig ex vivo model using 4.5 mm titanium LCP was created. It was subsequently computer-loaded by forces acting parallel to the long axis of the construct. By the effect of the acting forces the displacement vector sum of individual construct points occurred. The greatest displacement was noted in the end segments of the bone in close proximity to ostectomy and in the area of the empty central plate hole (without screw at the level of the segmental bone defect. By studying the equivalent von Mises stress σEQV on LCP as part of the tested construct we found that the greatest changes of stress occur in the place of the empty central plate hole. The distribution of this strain was relatively symmetrical along both sides of the hole. The exceeding of the yield stress value and irreversible plastic deformations in this segment of LCP occurred at the acting of the force of 360 N. These findings are in line with the character of damage of the same construct loaded during its mechanic testing. We succeeded in creating a mathematical model of the bone-implant construct which may be further used for computer modelling of real loading of similar constructs chosen for fixation of bone defects in both experimental and clinical practice.

  20. Short-term supplementation of low-dose gamma-linolenic acid (GLA), alpha-linolenic acid (ALA), or GLA plus ALA does not augment LCP omega 3 status of Dutch vegans to an appreciable extent

    NARCIS (Netherlands)

    Fokkema, M R; Brouwer, D A; Hasperhoven, M B; Martini, I A; Muskiet, F A

    Vegans do not consume meat and fish and have therefore low intakes of long chain polyunsaturated fatty acids (LCP). They may consequently have little negative feedback inhibition from dietary LCP on conversion of alpha -linolenic acid (ALA) to the LCP omega 3 eicosapentaenoic (EPA) and

  1. Light-controlled supramolecular helicity of a liquid crystalline phase using a helical polymer functionalized with a single chiroptical molecular switch

    NARCIS (Netherlands)

    Pijper, Dirk; Jongejan, Mahthild G. M.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    Control over the preferred helical sense of a poly(n-hexyl isocyanate) (PHIC) by using a single light-driven molecular motor, covalently attached at the polymer's terminus, has been accomplished in solution via a combination of photochemical and thermal isomerizations. Here, we report that after

  2. Organic Field-Effect Transistors Based on a Liquid-Crystalline Polymeric Semiconductor using SU-8 Gate Dielectrics on Flexible Substrates

    Science.gov (United States)

    Tetzner, Kornelius; Bose, Indranil R.; Bock, Karlheinz

    2014-01-01

    In this work, the insulating properties of poly(4-vinylphenol) (PVP) and SU-8 (MicroChem, Westborough, MA, USA) dielectrics are analyzed and compared with each other. We further investigate the performance behavior of organic field-effect transistors based on a semiconducting liquid-crystal polymer (LCP) using both dielectric materials and evaluate the results regarding the processability. Due to the lower process temperature needed for the SU-8 deposition, the realization of organic transistors on flexible substrates is demonstrated showing comparable charge carrier mobilities to devices using PVP on glass. In addition, a µ-dispensing procedure of the LCP on SU-8 is presented, improving the switching behavior of the organic transistors, and the promising stability data of the SU-8/LCP stack are verified after storing the structures for 60 days in ambient air showing negligible irreversible degradation of the organic semiconductor. PMID:28788243

  3. Organic Field-Effect Transistors Based on a Liquid-Crystalline Polymeric Semiconductor using SU-8 Gate Dielectrics onFlexible Substrates

    Directory of Open Access Journals (Sweden)

    Kornelius Tetzner

    2014-10-01

    Full Text Available In this work, the insulating properties of poly(4-vinylphenol (PVP and SU-8 (MicroChem, Westborough, MA, USA dielectrics are analyzed and compared with each other. We further investigate the performance behavior of organic field-effect transistors based on a semiconducting liquid-crystal polymer (LCP using both dielectric materials and evaluate the results regarding the processability. Due to the lower process temperature needed for the SU-8 deposition, the realization of organic transistors on flexible substrates is demonstrated showing comparable charge carrier mobilities to devices using PVP on glass. In addition, a µ-dispensing procedure of the LCP on SU-8 is presented, improving the switching behavior of the organic transistors, and the promising stability data of the SU-8/LCP stack are verified after storing the structures for 60 days in ambient air showing negligible irreversible degradation of the organic semiconductor.

  4. Organic Field-Effect Transistors Based on a Liquid-Crystalline Polymeric Semiconductor using SU-8 Gate Dielectrics onFlexible Substrates.

    Science.gov (United States)

    Tetzner, Kornelius; Bose, Indranil R; Bock, Karlheinz

    2014-10-29

    In this work, the insulating properties of poly(4-vinylphenol) (PVP) and SU-8 (MicroChem, Westborough, MA, USA) dielectrics are analyzed and compared with each other. We further investigate the performance behavior of organic field-effect transistors based on a semiconducting liquid-crystal polymer (LCP) using both dielectric materials and evaluate the results regarding the processability. Due to the lower process temperature needed for the SU-8 deposition, the realization of organic transistors on flexible substrates is demonstrated showing comparable charge carrier mobilities to devices using PVP on glass. In addition, a µ-dispensing procedure of the LCP on SU-8 is presented, improving the switching behavior of the organic transistors, and the promising stability data of the SU-8/LCP stack are verified after storing the structures for 60 days in ambient air showing negligible irreversible degradation of the organic semiconductor.

  5. Identification of three homologous latex-clearing protein (lcp) genes from the genome of Streptomyces sp. strain CFMR 7.

    Science.gov (United States)

    Nanthini, Jayaram; Ong, Su Yean; Sudesh, Kumar

    2017-09-10

    Rubber materials have greatly contributed to human civilization. However, being a polymeric material does not decompose easily, it has caused huge environmental problems. On the other hand, only few bacteria are known to degrade rubber, with studies pertaining them being intensively focusing on the mechanism involved in microbial rubber degradation. The Streptomyces sp. strain CFMR 7, which was previously confirmed to possess rubber-degrading ability, was subjected to whole genome sequencing using the single molecule sequencing technology of the PacBio® RS II system. The genome was further analyzed and compared with previously reported rubber-degrading bacteria in order to identify the potential genes involved in rubber degradation. This led to the interesting discovery of three homologues of latex-clearing protein (Lcp) on the chromosome of this strain, which are probably responsible for rubber degrading activities. Genes encoding oxidoreductase α-subunit (oxiA) and oxidoreductase β-subunit (oxiB) were also found downstream of two lcp genes which are located adjacent to each other. In silico analysis reveals genes that have been identified to be involved in the microbial degradation of rubber in the Streptomyces sp. strain CFMR 7. This is the first whole genome sequence of a clear-zone-forming natural rubber- degrading Streptomyces sp., which harbours three Lcp homologous genes with the presence of oxiA and oxiB genes compared to the previously reported Gordonia polyisoprenivorans strain VH2 (with two Lcp homologous genes) and Nocardia nova SH22a (with only one Lcp gene). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. VA-LCP anterior clavicle plate: the anatomically precontoured fixation system with angular stability for clavicle shaft.

    Science.gov (United States)

    van Olden, G D J

    2014-12-01

    The aim of this investigation was to evaluate the introduction of the VA-LCP anterior clavicle plate in the treatment of clavicle fractures. From March 2011 to March 2013, 42 clavicle fractures were treated; 40 were middle-third and 2 lateral-third, and 13/42 (31 %) patients were treated due to painful nonunion. Patient age ranged from 16 to 81 years. Complications were screw placement through the AC-joint, one superficial wound infection and one neuropraxia of the nervus radialis with dropping hand. We had some difficulties prebending both lateral to low and lateral to high but without clinical consequences. In all cases, the fracture healed with full functionality. After 1 year, 4 patients underwent a removal of the hardware. The VA-LCP anterior plate showed good reliability and sufficient stability with both middle-third, lateral and nonunion fractures of the clavicle.

  7. Emission inventory for large combustion plants in France according to the 2001/80/CE European directive - LCP - February 2010

    International Nuclear Information System (INIS)

    Chang, Jean-Pierre; Fontelle, Jean-Pierre; Gavel, Antoine; Vincent, Julien; Matthias, Etienne; Druart, Ariane; Jacquier, Guillaume; Nicco, Laetitia

    2010-02-01

    After a recall of the methodological aspects of this inventory (scope of application, concept of existing or new installation, thermal power, fuels, considered pollutants, equipment, data acquisition and processing), this report presents the national results: typology of large combustion plant (LCP) installations, energy consumption, atmospheric emissions (sulphur dioxide, nitrogen dioxide, particles), emission distribution per energy type, sector-based distribution of LCPs. It also presents regional results (for 2008 and evolutions in 2009)

  8. Bio-based liquid crystalline polyesters

    Science.gov (United States)

    Wilsens, Carolus; Rastogi, Sanjay; Dutch Collaboration

    2013-03-01

    The reported thin-film polymerization has been used as a screening method in order to find bio-based liquid crystalline polyesters with convenient melting temperatures for melt-processing purposes. An in depth study of the structural, morphological and chemical changes occurring during the ongoing polycondensation reactions of these polymers have been performed. Structural and conformational changes during polymerization for different compositions have been followed by time resolved X-ray and Infrared spectroscopy. In this study, bio-based monomers such as vanillic acid and 2,5-furandicarboxylic acid are successfully incorporated in liquid crystalline polyesters and it is shown that bio-based liquid crystalline polymers with high aromatic content and convenient processing temperatures can be synthesized. Special thanks to the Dutch Polymer Institute for financial support

  9. Hierarchical self-assembly, coassembly, and self-organization of novel liquid crystalline lattices and superlattices from a twin-tapered dendritic benzamide and its four-cylinder-bundle supramolecular polymer.

    Science.gov (United States)

    Percec, Virgil; Bera, Tushar K; Glodde, Martin; Fu, Qiongying; Balagurusamy, Venkatachalapathy S K; Heiney, Paul A

    2003-02-17

    The synthesis and structural analysis of the twin-dendritic benzamide 10, based on the first-generation, self-assembling, tapered dendrons 3,4,5-tris(4'-dodecyloxybenzyloxy)benzoic acid and 3,4,5-tris(4'-dodecyloxybenzyloxy)-1-aminobenzene, and the polymethacrylate, 20, which contains 10 as side groups, are presented. Benzamide 10 self-assembles into a supramolecular cylindrical dendrimer that self-organizes into a columnar hexagonal (Phi(h)) liquid crystalline (LC) phase. Polymer 20 self-assembles into an imperfect four-cylinder-bundle supramolecular dendrimer, and creates a giant vesicular supercylinder that self-organizes into a columnar nematic (N(c)) LC phase which displays short-range hexagonal order. In mixtures of 20 and 10, 10 acts as a guest and 20 as a host to create a perfect four-cylinder-bundle host-guest supramolecular dendrimer that coorganizes with 10. A diversity of Phi(h), simple rectangular columnar (Phi(r-s)) and centered rectangular columnar (Phi(r-c)), superlattices are produced at different ratios between 20 and 10. This diversity of LC lattices and superlattices is facilitated by the architecture of the twin-dendritic building block, polymethacrylate, the host-guest supramolecular assembly, and by hydrogen bonding along the center of the supramolecular cylinders generated from 10 and 20.

  10. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  11. Structural Analysis of Aromatic Liquid Crystalline Polyesters

    Directory of Open Access Journals (Sweden)

    Arpad Somogyi

    2011-01-01

    Full Text Available Laboratory preparations of liquid crystalline prepolymers, distillates accompanying prepolymers, final polymers, and sublimates accompanying final polymers were examined. NaOD/D2O depolymerization of prepolymers and polymers back to monomers with integration of the 1H NMR spectra showed up to 6% excess of carboxyls over phenol groups, caused partly by loss of the low-boiling comonomer hydroquinone through distillation during prepolymerization and leaving anhydride units in the polymer chain. ESI− MS and MS/MS of hexafluoroisopropanol extracts of the prepolymer detected small molecules including some containing anhydride groups; ESI+ MS showed the presence of small cyclic oligomers. 1H NMR (including TOCSY spectra provided more quantitative analyses of these oligomers. The final polymerization increases the length of the polymer chains and sublimes out the small oligomers. Anhydride linkages remaining in the polymer must make LCP’s more susceptible to degradation by nucleophilic reagents such as water, alkalis, and amines.

  12. Diketopyrrolopyrrole polymers for organic solar cells

    NARCIS (Netherlands)

    Li, Wei Wei; Hendriks, K.H.; Wienk, M.M.; Janssen, R.A.J.

    2016-01-01

    Conspectus Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a

  13. LCP crystallization and X-ray diffraction analysis of VcmN, a MATE transporter from Vibrio cholerae

    Energy Technology Data Exchange (ETDEWEB)

    Kusakizako, Tsukasa [Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan); Tanaka, Yoshiki [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192 (Japan); Hipolito, Christopher J. [Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575 (Japan); Kuroda, Teruo [Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Ishitani, Ryuichiro [Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan); Suga, Hiroaki [Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nureki, Osamu, E-mail: nureki@bs.s.u-tokyo.ac.jp [Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan)

    2016-06-22

    A V. cholerae MATE transporter was crystallized using the lipidic cubic phase (LCP) method. X-ray diffraction data sets were collected from single crystals obtained in a sandwich plate and a sitting-drop plate to resolutions of 2.5 and 2.2 Å, respectively. Multidrug and toxic compound extrusion (MATE) transporters, one of the multidrug exporter families, efflux xenobiotics towards the extracellular side of the membrane. Since MATE transporters expressed in bacterial pathogens contribute to multidrug resistance, they are important therapeutic targets. Here, a MATE-transporter homologue from Vibrio cholerae, VcmN, was overexpressed in Escherichia coli, purified and crystallized in lipidic cubic phase (LCP). X-ray diffraction data were collected to 2.5 Å resolution from a single crystal obtained in a sandwich plate. The crystal belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 52.3, b = 93.7, c = 100.2 Å. As a result of further LCP crystallization trials, crystals of larger size were obtained using sitting-drop plates. X-ray diffraction data were collected to 2.2 Å resolution from a single crystal obtained in a sitting-drop plate. The crystal belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 61.9, b = 91.8, c = 100.9 Å. The present work provides valuable insights into the atomic resolution structure determination of membrane transporters.

  14. Crystalline and Crystalline International Disposal Activities

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-21

    This report presents the results of work conducted between September 2014 and July 2015 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program.

  15. Molecular Engineering of Liquid Crystalline Polymers

    Science.gov (United States)

    1992-03-27

    Szasz , N. Sheppard and D. H. Rank, J. Chem. Phys., 1948, 16..704 119. P. B. Woller and E. W. Garbisch, Jr., J. Am. Chem. Soc., 1972, 94, 53 10 120. A. L...schematic representation of a sanidic (from Greek for boardlike) mesophase.202 Figure 15. a) Layer spacing d calculated according to Bragg’s law

  16. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  17. Impaired maternal glucose homeostasis during pregnancy is associated with low status of long-chain polyunsaturated fatty acids (LCP) and essential fatty acids (EFA) in the fetus

    NARCIS (Netherlands)

    Dijck-Brouwer, DAJ; Hadders-Algra, M; Bouwstra, H; Decsi, T; Boehm, G; Martini, IA; Boersma, ER; Muskiet, FAJ

    Low status of long-chain polyunsaturated fatty acids (LCP) and essential fatty acids (EFA) in the fetus is associated with less favorable neonatal neurological condition. A 'relative', rather than 'absolute' EFA deficiency might explain this finding. A relative EFA deficiency may derive from

  18. Crystalline and Crystalline International Disposal Activities

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Hari S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, Timothy M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, Jeffrey De' Haven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, Nataliia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-06

    This report presents the results of work conducted between September 2015 and July 2016 at Los Alamos National Laboratory in the crystalline disposal and crystalline international disposal work packages of the Used Fuel Disposition Campaign (UFDC) for DOE-NE’s Fuel Cycle Research and Development program. Los Alamos focused on two main activities during this period: Discrete fracture network (DFN) modeling to describe flow and radionuclide transport in complex fracture networks that are typical of crystalline rock environments, and a comprehensive interpretation of three different colloid-facilitated radionuclide transport experiments conducted in a fractured granodiorite at the Grimsel Test Site in Switzerland between 2002 and 2013. Chapter 1 presents the results of the DFN work and is divided into three main sections: (1) we show results of our recent study on the correlation between fracture size and fracture transmissivity (2) we present an analysis and visualization prototype using the concept of a flow topology graph for characterization of discrete fracture networks, and (3) we describe the Crystalline International work in support of the Swedish Task Force. Chapter 2 presents interpretation of the colloidfacilitated radionuclide transport experiments in the crystalline rock at the Grimsel Test Site.

  19. Contact mechanics in glassy polymers

    NARCIS (Netherlands)

    Breemen, van L.C.A.

    2009-01-01

    Polymers, primarily semi-crystalline, are widely used in applications where low friction is required; examples are cups in artificial hip joints, bearings and gears. Until now there is no clear indication why some polymers display low friction and others don’t. In this thesis a systematic

  20. Crystalline Silica Primer

    Science.gov (United States)

    ,

    1992-01-01

    Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a threedimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHAregulated businesses that use materials containing 0.1% or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHAregulated

  1. What Is Crystalline Silica?

    Science.gov (United States)

    ... and ceramic manufacturing and the tool and die, steel and foundry industries. Crystalline silica is used in manufacturing, household abrasives, adhesives, paints, soaps, and glass. Additionally, ...

  2. Crystallinity evaluation of polyhydroxybutyrate and polycaprolactone blends

    International Nuclear Information System (INIS)

    Cavalcante, Maxwell P.; Rodrigues, Elton Jorge R.; Tavares, Maria Ines B.

    2015-01-01

    Polyhydroxybutyrate, PHB, is a polymer obtained through bacterial or synthetic pathways. It has been used in the biomedical field as a matrix for drug delivery, medical implants and as scaffold material for tissue engineering. PHB has high structural organization, which makes it highly crystalline and brittle, making biodegradation difficult, reducing its employability. In order to enhance the mechanical and biological properties of PHB, blends with other polymers, biocompatible or not, are researched and produced. In this regard, blends of PHB and polycaprolactone, PCL, another biopolymer widely used in the biomedical industry, were obtained via solution casting and were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and low field nuclear magnetic resonance (LF-NMR). Results have shown a dependence between PHB's crystallinity index and PCL quantity employed to obtain the blends.(author)

  3. Controlled synthesis of single-crystalline graphene

    Directory of Open Access Journals (Sweden)

    Wang Xueshen

    2014-02-01

    Full Text Available This paper reports the controlled synthesis of single-crystalline graphene on the back side of copper foil using CH4 as the precursor. The influence of growth time and the pressure ratio of CH4/H2 on the structure of graphene are examined. An optimized polymer-assisted method is used to transfer the synthesized graphene onto a SiO2/Si substrate. Scanning electron microscopy and Raman spectroscopy are used to characterize the graphene.

  4. Piezoelectric Flexible LCP-PZT Composites for Sensor Applications at Elevated Temperatures

    Science.gov (United States)

    Tolvanen, Jarkko; Hannu, Jari; Juuti, Jari; Jantunen, Heli

    2018-03-01

    In this paper fabrication of piezoelectric ceramic-polymer composites is demonstrated via filament extrusion enabling cost-efficient large-scale production of highly bendable pressure sensors feasible for elevated temperatures. These composites are fabricated by utilizing environmentally resistant and stable liquid crystal polymer matrix with addition of lead zirconate titanate at loading levels of 30 vol%. These composites, of approximately 0.99 mm thick and length of > 50 cm, achieved excellent bendability with minimum bending radius of 6.6 cm. The maximum piezoelectric coefficients d33 and g33 of the composites were > 14 pC/N and > 108 mVm/N at pressure < 10 kPa. In all cases, the piezoelectric charge coefficient (d33) of the composites decreased as a function of pressure. Also, piezoelectric coefficient (d33) further decreased in the case of increased frequency press-release cycle sand pre-stress levels by approximately 37-50%. However, the obtained results provide tools for fabricating novel piezoelectric sensors in highly efficient way for environments with elevated temperatures.

  5. Midterm Follow-up of Treating Volar Marginal Rim Fractures with Variable Angle Lcp Volar Rim Distal Radius Plates.

    Science.gov (United States)

    Goorens, Chul Ki; Geeurickx, Stijn; Wernaers, Pascal; Staelens, Barbara; Scheerlinck, Thierry; Goubau, Jean

    2017-06-01

    Specific treatment of the volar marginal rim fragment of distal radius fractures avoids occurance of volar radiocarpal dislocation. Although several fixation systems are available to capture this fragment, adequately maintaining internal fixation is difficult. We present our experience of the first 10 cases using the 2.4 mm variable angle LCP volar rim distal radius plate (Depuy Synthes®, West Chester, US), a low-profile volar rim-contouring plate designed for distal plate positioning and stable buttressing of the volar marginal fragment. Follow-up patient satisfaction, range of motion, grips strength, functional scoring with the QuickDASH and residual pain with a numeric rating scale were assessed. Radiological evaluation consisted in evaluating fracture consolidation, ulnar variance, volar angulation and maintenance of the volar rim fixation. The female to male ratio was 5:5 and the mean age was 52.2 (range, 17-80) years. The mean follow-up period was 11 (range, 5-19) months postoperatively. Patient satisfaction was high. The mean total flexion/extension range was 144° (range, 100-180°) compared to the contralateral uninjured side 160° (range, 95-180°). The mean total pronation/supination range was 153° (range, 140-180°) compared to the contralateral uninjured side 170° (range, 155-180°). Mean grip strength was 14 kg (range, 9-22), compared to the contralateral uninjured side 20 kg (range, 12-25 kg). Mean pre-injury level activity QuickDASH was 23 (range, 0-34.1), while post-recovery QuickDASH was 25 (range 0-43.2). Residual pain was 1.5 on the visual numerical pain rating scale. Radiological evaluation revealed in all cases fracture consolidation, satisfactory reconstruction of ulnar variance, volar angulation and volar rim. We encountered no flexor tendon complications, although plate removal was systematically performed after fracture consolidation. The 2.4 mm variable angle LCP volar rim distal radius plates is a valid treatment option for treating

  6. Liquid crystallinity driven highly aligned large graphene oxide composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Eun; Oh, Jung Jae; Yun, Taeyeong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of); Kim, Sang Ouk, E-mail: sangouk.kim@kaist.ac.kr [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701 (Korea, Republic of); Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701 (Korea, Republic of)

    2015-04-15

    Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase, LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.

  7. Crystallinity and mechanical effects from annealing Parylene thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Nathan, E-mail: Nathan.Jackson@tyndall.ie [Tyndall National Institute, University College Cork, Cork (Ireland); Stam, Frank; O' Brien, Joe [Tyndall National Institute, University College Cork, Cork (Ireland); Kailas, Lekshmi [University of Limerick, Limerick (Ireland); Mathewson, Alan; O' Murchu, Cian [Tyndall National Institute, University College Cork, Cork (Ireland)

    2016-03-31

    Parylene is commonly used as thin film polymer for MEMS devices and smart materials. This paper investigates the impact on bulk properties due to annealing various types of Parylene films. A thin film of Parylene N, C and a hybrid material consisting of Parylene N and C were deposited using a standard Gorham process. The thin film samples were annealed at varying temperatures from room temperature up to 300 °C. The films were analyzed to determine the mechanical and crystallinity effects due to different annealing temperatures. The results demonstrate that the percentage of crystallinity and the full-width-half-maximum value on the 2θ X-ray diffraction scan increases as the annealing temperature increases until the melting temperature of the Parylene films was achieved. Highly crystalline films of 85% and 92% crystallinity were achieved for Parylene C and N respectively. Investigation of the hybrid film showed that the individual Parylene films behave independently to each other, and the crystallinity of one film had no significant impact to the other film. Mechanical testing showed that the elastic modulus and yield strength increase as a function of annealing, whereas the elongation-to-break parameter decreases. The change in elastic modulus was more significant for Parylene C than Parylene N and this is attributed to the larger change in crystallinity that was observed. Parylene C had a 112% increase in crystallinity compared to a 61% increase for Parylene N, because the original Parylene N material was more crystalline than Parylene C so the change of crystallinity was greater for Parylene C. - Highlights: • A hybrid material consisting of Parylene N and C was developed. • Parylene N has greater crystallinity than Parylene C. • Phase transition of Parylene N due to annealing results in increased crystallinity. • Annealing caused increased crystallinity and elastic modulus in Parylene films. • Annealed hybrid Parylene films crystallinity behave

  8. Crystalline color superconductivity

    International Nuclear Information System (INIS)

    Alford, Mark; Bowers, Jeffrey A.; Rajagopal, Krishna

    2001-01-01

    In any context in which color superconductivity arises in nature, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with nonzero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde, and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. Unlike the original LOFF state, these crystalline quark matter condensates include both spin-zero and spin-one Cooper pairs. We explore the range of parameters for which crystalline color superconductivity arises in the QCD phase diagram. If in some shell within the quark matter core of a neutron star (or within a strange quark star) the quark number densities are such that crystalline color superconductivity arises, rotational vortices may be pinned in this shell, making it a locus for glitch phenomena

  9. Neutron scattering studies of molecular conformations in liquid crystal polymers

    Science.gov (United States)

    Noirez, L.; Moussa, F.; Cotton, J. P.; Keller, P.; Pépy, G.

    1991-03-01

    A comblike liquid crystal polymer (LPC) is a polymer on which mesogenic molecules have been grafted. It exhibits a succession of liquid crystal phases. Usually the equilibrium conformation of an ordinary polymeric chain corresponds to a maximum entropy, i.e., to an isotropic spherical coil. How does the backbone of a LCP behave in the nematic and smectic field? Small-angle neutron scattering may answer this question. Such measurements are presented here on four different polymers as a function of temperature. An anisotropy of the backbone conformation is found in all these studied compounds, much more pronounced in the smectic phase than in the nematic phase: the backbone spreads more or less perpendicularly to its hanging cores. A comparison with existing theories and a discussion of these results is outlined.

  10. Molecular and supramolecular orientation in conducting polymers

    International Nuclear Information System (INIS)

    Aldissi, M.

    1987-01-01

    Intrinsic anisotropy in electrical and optical properties of conducting polymers constitutes a unique aspect that derives π-electron delocalization along the polymer backbone and from the weak inter-chain interaction. To acquire such an intrinsic property, conducting polymers have to be oriented macroscopically and microscopically (at the chain level). A review of the various techniques, including stretch-alignment of the polymer and of precursor polymers, polymerization in ordered media, i.e., in a liquid crystal solvent, and synthesis of liquid crystalline conducting polymers will be given. 29 refs

  11. Dissolution of crystalline ceramics

    International Nuclear Information System (INIS)

    White, W.B.

    1982-01-01

    The present program objectives are to lay out the fundamentals of crystalline waste form dissolution. Nuclear waste ceramics are polycrystalline. An assumption of the work is that to the first order, the release rate of a particular radionuclide is the surface-weighted sum of the release rates of the radionuclide from each crystalline form that contains it. In the second order, of course, there will be synergistic effects. There will be also grain boundary and other microstructural influences. As a first approximation, we have selected crystalline phases one at a time. The sequence of investigations and measurements is: (i) Identification of the actual chemical reactions of dissolution including identification of the solid reaction products if such occur. (ii) The rates of these reactions are then determined empirically to give what may be called macroscopic kinetics. (iii) Determination of the rate-controlling mechanisms. (iv) If the rate is controlled by surface reactions, the final step would be to determine the atomic kinetics, that is the specific atomic reactions that occur at the dissolving interface. Our concern with the crystalline forms are in two areas: The crystalline components of the reference ceramic waste form and related ceramics and the alumino-silicate phases that appear in some experimental waste forms and as waste-rock interaction products. Specific compounds are: (1) Reference Ceramic Phases (zirconolite, magnetoplumbite, spinel, Tc-bearing spinel and perovskite); (2) Aluminosilicate phases (nepheline, pollucite, CsAlSi 5 O 12 , Sr-feldspar). 5 figures, 1 table

  12. Self-assembly of azobenzene based side-chain liquid crystalline ...

    Indian Academy of Sciences (India)

    The polymeric complexes acquitted as undivided liquid crystalline properties ... India) methanol and other solvents were purified by .... mixture was warmed to room temperature and stirred ... Polymer is soluble in DMF, CHCl3, CH2Cl2 and.

  13. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru

    2010-01-01

    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattices, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. This book is divided into three parts. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. In the third part, the multi-electron system is discussed theoretically, as a quantum-mechanical example, for the superconducting state in metallic crystals. Throughout the book, the role played by the lattice is emphasized and examined in-depth. Thermodynamics of Crystalline States is an introductory treatise and textbook on meso...

  14. Liquid crystalline dihydroazulene photoswitches

    DEFF Research Database (Denmark)

    Petersen, Anne Ugleholdt; Jevric, Martyn; Mandle, Richard J.

    2015-01-01

    A large selection of photochromic dihydroazulene (DHA) molecules incorporating various substituents at position 2 of the DHA core was prepared and investigated for their ability to form liquid crystalline phases. Incorporation of an octyloxy-substituted biphenyl substituent resulted in nematic...... phase behavior and it was possible to convert one such compound partly into its vinylheptafulvene (VHF) isomer upon irradiation with light when in the liquid crystalline phase. This conversion resulted in an increase in the molecular alignment of the phase. In time, the meta-stable VHF returns...... to the DHA where the alignment is maintained. The systematic structural variation has revealed that a biaryl spacer between the DHA and the alkyl chain is needed for liquid crystallinity and that the one aromatic ring in the spacer cannot be substituted by a triazole. This work presents an important step...

  15. Calcium carbonate interaction analysis in polypropylene compounds and their impact on the formation of beta crystalline phase of this polymer; Analise da interacao de diferentes tipos de carbonato de calcio em compositos de polipropileno e suas consequencias na formacao da fase cristalina beta do PP

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The insertion of calcium carbonate (CaCO{sub 3}) in polypropylene compound is a thoroughly known technique widely studied in the academic area and in the industry. Its wide application is due, mainly, to increase mechanical properties with low manufacturing cost. These improvements in this polymer make it more versatile and competitive compared to other expensive polymers. In this study, the incorporation of four types of CaCO3 from the same manufacturer were compared and the focus was on the size of this mineral filler. Furthermore, it was analyzed the interaction of graphitized polypropylene with maleic anhydride (PP-g-MA) in the same samples. All these samples were analyzed by WAXS and SEM. The physical properties of tensile strength and impact were also analyzed. It was observed from this study that the smallest CaCO3 produced with PP-g-MA resulted in better physical properties with the formation of a crystalline phase beta, as originally studied by other authors using other raw materials. (author)

  16. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  17. Effect of carbon derivatives in sulfonated poly(etherimide)-liquid crystal polymer composite for methanol vapor sensing

    Science.gov (United States)

    Bag, Souvik; Rathi, Keerti; Pal, Kaushik

    2017-05-01

    A class of highly sensitive chemiresistive sensors is developed for methanol (MeOH) vapor detection in ambient atmosphere by introducing conductive nanofillers like carbon black, multi-wall carbon nanotubes, and reduced graphene oxide into sulfonated poly(etherimide) (PEI)/liquid crystal polymer (LCP) composite (sPEI-LCP). Polar composites are prepared by a sulfonation process for instantaneous enhancement in adsorption capability of the sensing films to the target analyte (MeOH). Sensing properties exhibit that polymer composite-based fabricated sensors are efficient for the detection of different concentration of methanol vapor from 300-1200 parts-per-million (ppm) at room temperature. The incorporation of nanofiller induces the dramatic change in sensing behavior of base composite film (sPEI-LCP). Thus, less mass fraction of nanofillers (i.e. 2 wt%) influences the nonlinear sensing behavior for the entire range of methanol vapor. The simple method and low fabrication cost of the prepared sensor are compelling reasons that methanol vapor sensor is suitable for environmental monitoring.

  18. A liquid crystal polymer membrane MEMS sensor for flow rate and flow direction sensing applications

    International Nuclear Information System (INIS)

    Kottapalli, A G P; Tan, C W; Olfatnia, M; Miao, J M; Barbastathis, G; Triantafyllou, M

    2011-01-01

    The paper reports the design, fabrication and experimental results of a liquid crystal polymer (LCP) membrane-based pressure sensor for flow rate and flow direction sensing applications. Elaborate experimental testing results demonstrating the sensors' performance as an airflow sensor have been illustrated and validated with theory. MEMS sensors using LCP as a membrane structural material show higher sensitivity and reliability over silicon counterparts. The developed device is highly robust for harsh environment applications such as atmospheric wind flow monitoring and underwater flow sensing. A simple, low-cost and repeatable fabrication scheme has been developed employing low temperatures. The main features of the sensor developed in this work are a LCP membrane with integrated thin film gold piezoresistors deposited on it. The sensor developed demonstrates a good sensitivity of 3.695 mV (ms −1 ) −1 , large operating range (0.1 to >10 ms −1 ) and good accuracy in measuring airflow with an average error of only 3.6% full-scale in comparison with theory. Various feasible applications of the developed sensor have been demonstrated with experimental results. The sensor was tested for two other applications—in clinical diagnosis for breath rate, breath velocity monitoring, and in underwater applications for object detection by sensing near-field spatial flow pressure

  19. Strain hardening and anisotropy in solid polymers

    NARCIS (Netherlands)

    Senden, D.J.A.

    2013-01-01

    Mechanical properties of polymers strongly depend on the underlying microstructure. For instance, processing-induced molecular orientation may, in semi-crystalline polymers, lead to differences in lifetime up to a factor of 500 within a single injection molded product. Furthermore, enormous

  20. Crystalline structure of metals

    International Nuclear Information System (INIS)

    Holas, A.

    1972-01-01

    An attempt is made to find the crystalline structure of metals on the basis of the existing theory of metals. The considerations are limited to the case of free crystals, that is, not subjected to any stresses and with T=0. The energy of the crystal lattice has been defined and the dependence of each term on structures and other properties of metals has been described. The energy has been used to find the values of crystalline structure parameters as the values at which the energy has an absolute minimum. The stability of the structure has been considered in cases of volume changes and shearing deformations. A semiqualitative description has been obtained which explains characteristic properties of one-electron metals. (S.B.)

  1. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru

    2013-01-01

    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium with the surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattice, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. New to this edition is the examination of magnetic crystals, where magnetic symmetry is essential for magnetic phase transitions. The multi-electron system is also discussed  theoretically, as a quantum-mechanical example, for superconductivity in metallic crystals. Throughout the book, the role played by the lattice is emphasized and studied in-depth. Thermod...

  2. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, Jie; Li, Xiao-Ping

    1993-01-01

    In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Schiffer et al. depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  3. Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

    KAUST Repository

    Cates, Nichole C.; Gysel, Roman; Dahl, Jeremy E. P.; Sellinger, Alan; McGehee, Michael D.

    2010-01-01

    Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study

  4. WORKSHOP: Crystalline beams

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Following pioneer work by specialists at the Soviet Novosibirsk Laboratory some ten years ago, interest developed in the possibility of 'freezing' ion beams in storage rings by pushing cooling (to smooth out beam behaviour) to its limits, the final goal being to lock the ions into a neat crystal pattern. After advances by groups working on laser cooled ions in traps, and with several cooling rings now in operation, a workshop on crystalline ion beams was organized recently by the GSI (Darmstadt) Laboratory and held at Wertheim in Germany

  5. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, Jie; Li, Xiao-Ping; Sessler, A.M.

    1993-01-01

    In order to employ Molecular Dynamics method, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  6. Crystalline beam ground state

    International Nuclear Information System (INIS)

    Wei, J.; Li, X.P.

    1993-01-01

    In order to employ the Molecular Dynamics method, commonly used in condensed matter physics, the authors have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. They include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations has been performed to obtain the equilibrium structure. The effects of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time-dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Rahman and Schiffer, depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing

  7. Biodegradable Polymers

    OpenAIRE

    Vroman, Isabelle; Tighzert, Lan

    2009-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  8. Letter from Kirk Kessler, EPS to Galo Jackson, USEPA. Subject: Results of the July 2011 Sampling in the Former Brunswick-Altamaha Canal South of the LCP Chemicals Site, Brunswick, Ga, Revision Dated April 19, 2012

    Science.gov (United States)

    Results report of sediment and fish tissue samples collected from the former Brunswick-Altamaha Canal, in a segment of the canal south of the LCP Chemicals Site in Brunswick, Georgia in July 2010. Region ID: 04 DocID: 10843428, DocDate: 04-19-2012

  9. Crystallinity of Electrospun and Centrifugal Spun Polycaprolactone Fibers: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Eva Kuzelova Kostakova

    2017-01-01

    Full Text Available Crystalline properties of semicrystalline polymers are very important parameters that can influence the application area. The internal structure, like the mentioned crystalline properties, of polymers can be influenced by the production technology itself and by changing technology parameters. The present work is devoted to testing of electrospun and centrifugal spun fibrous and nanofibrous materials and compare them to foils and granules made from the same raw polymer. The test setup reveals the structural differences caused by the production technology. Effects of average molecular weight are also exhibited. The applied biodegradable and biocompatible polymer is polycaprolactone (PCL as it is a widespread material for medical purposes. The crystallinity of PCL has significant effect on rate of degradation that is an important parameter for a biodegradable material and determines the applicability. The results of differential scanning calorimetry (DSC showed that, at the degree of crystallinity, there is a minor difference between the electrospun and centrifugal spun fibrous materials. However, the significant influence of polymer molecular weight was exhibited. The morphology of the fibrous materials, represented by fiber diameter, also did not demonstrate any connection to final measured crystallinity degree of the tested materials.

  10. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  11. Groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    Palmqvist, K.

    1990-06-01

    The aim of this project was to make detailed descriptions of the geological conditions and the different kinds of leakage in some tunnels in Sweden, to be able to describe the presence of ground water in crystalline bedrock. The studies were carried out in TBM tunnels as well as in conventionally drilled and blasted tunnels. Thanks to this, it has been possible to compare the pattern and appearance of ground water leakage in TBM tunnels and in blasted tunnels. On the basis of some experiments in a TBM tunnel, it has been confirmed that a detailed mapping of leakage gives a good picture of the flow paths and their aquiferous qualities in the bedrock. The same picture is found to apply even in cautious blasted tunnels. It is shown that the ground water flow paths in crystalline bedrock are usually restricted to small channels along only small parts of the fractures. This is also true for fracture zones. It has also been found that the number of flow paths generally increases with the degree of tectonisation, up to a given point. With further tectonisation the bedrock is more or less crushed which, along with mineral alteration, leaves only a little space left for the formation of water channels. The largest individual flow paths are usually found in fracture zones. The total amount of ground water leakage per m tunnel is also greater in fracture zones than in the bedrock between the fracture zones. In mapping visible leakage, five classes have been distinguished according to size. Where possible, the individual leak inflow has been measured during the mapping process. The quantification of the leakage classes made in different tunnels are compared, and some quantification standards suggested. A comparison of leakage in different rock types, tectonic zones, fractures etc is also presented. (author)

  12. Novel polypyrrole films with excellent crystallinity and good thermal stability

    International Nuclear Information System (INIS)

    Jeeju, Pullarkat P.; Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M.; Jayalekshmi, Sankaran

    2012-01-01

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: ► Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. ► The solution casted films exhibit semi-crystallinity and good thermal stability. ► Percentage crystallinity estimated using XRD and DSC analysis is about 65%. ► Raman studies support the enhancement in crystallinity based on XRD and DSC data. ► The conductivity of the film is 30 times higher than that of HCl doped sample.

  13. Novel polypyrrole films with excellent crystallinity and good thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Jeeju, Pullarkat P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Jayalekshmi, Sankaran, E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India)

    2012-06-15

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: Black-Right-Pointing-Pointer Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. Black-Right-Pointing-Pointer The solution casted films exhibit semi-crystallinity and good thermal stability. Black-Right-Pointing-Pointer Percentage crystallinity estimated using XRD and DSC analysis is about 65%. Black-Right-Pointing-Pointer Raman studies support the enhancement in crystallinity based on XRD and DSC data. Black-Right-Pointing-Pointer The conductivity of the film is 30 times higher than that of HCl doped sample.

  14. Polymer compound

    NARCIS (Netherlands)

    1995-01-01

    A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

  15. Amorphous and Crystalline Particulates: Challenges and Perspectives in Drug Delivery.

    Science.gov (United States)

    Al-Obaidi, Hisham; Majumder, Mridul; Bari, Fiza

    2017-01-01

    Crystalline and amorphous dispersions have been the focus of academic and industrial research due to their potential role in formulating poorly water-soluble drugs. This review looks at the progress made starting with crystalline carriers in the form of eutectics moving towards more complex crystalline mixtures. It also covers using glassy polymers to maintain the drug as amorphous exhibiting higher energy and entropy. However, the amorphous form tends to recrystallize on storage, which limits the benefits of this approach. Specific interactions between the drug and the polymer may retard this spontaneous conversion of the amorphous drug. Some studies have shown that it is possible to maintain the drug in the amorphous form for extended periods of time. For the drug and the polymer to form a stable mixture they have to be miscible on a molecular basis. Another form of solid dispersions is pharmaceutical co-crystals, for which research has focused on understanding the chemistry, crystal engineering and physico-chemical properties. USFDA has issued a guidance in April 2013 suggesting that the co-crystals as a pharmaceutical product may be a reality; but just not yet! While some of the research is still oriented towards application of these carriers, understanding the mechanism by which drug-carrier miscibility occurs is also covered. Within this context is the use of thermodynamic models such as Flory-Huggins model with some examples of studies used to predict miscibility. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  17. [Calcaneal fractures treated by open reduction and internal fixation with a locking compression plate (LCP). A prospective study. part I: basic analysis of the group].

    Science.gov (United States)

    Svatoš, F; Bartoška, R; Skála-Rosenbaum, J; Douša, P; Pacovský, V; Krbec, M

    2011-01-01

    In a prospective study of patients with calcaneal fractures treated by open reduction from an extensile lateral approach and LCP osteosynthesis, the authors evaluated the basic epidemiological data, mechanism of injury, type of fracture, essential data on surgery, days of hospital stay and the number of complications. In the period from September 1, 2006 to July 31, 2010, a total of 230 patients with 243 calcaneal fractures were treated. The fractures were classified as either open or closed and according to the Essex-Lopresti system. Of the total number of patients, 135 (55.6 % of all fractures) were indicated for conservative treatment and 108 (44.4% of all fractures) for surgical intervention. Indications for surgery based on the generally accepted criteria enabled us to select 77 patients with 82 fractures (33.7 % of all fractures) for treatment by the method of open reduction and LCP osteosynthesis. These patients constituted the group evaluated here. The other patients were treated using other techniques (21 fractures, i.e., 8.6 % of all fractures, by the Stehlík-Štulík transfixation method and further five [2.1 %] by screw osteosynthesis). Six surgeons were involved in the treatment of this group. For the diagnosis of fractures, plain radiographs in lateral and axial projection and axial and coronal CT images were used. All fractures were treated after subsidence of oedema by the method of open reduction and LCP fixation from an extensile lateral approach, with the use of a tourniquet. The follow-up period for the evaluation of functional outcome and bone union was 3 to 48 months. Fifty patients were followed up for over one year. The group evaluated comprised 58 men (75.3 %) with 63 fractures (76.8 %) and 19 women (24.7 %) with 19 fractures (23.2 %). The average age of the group was 42 years, with 41 years (range, 22-61 years) in men and 47 years (range, 30-70 years) in women. The most frequent cause of injury was a fall from a height below 1 metre and

  18. Alpha B- and βA3-crystallins containing d-aspartic acids exist in a monomeric state.

    Science.gov (United States)

    Sakaue, Hiroaki; Takata, Takumi; Fujii, Norihiko; Sasaki, Hiroshi; Fujii, Noriko

    2015-01-01

    Crystallin stability and subunit-subunit interaction are essential for eye lens transparency. There are three types of crystallins in lens, designated as α-, β-, and γ-crystallins. Alpha-crystallin is a hetero-polymer of about 800kDa, consisting of 35-40 subunits of two different αA- and αB-subunits, each of 20kDa. The β/γ-crystallin superfamily comprises oligomeric β-crystallin (2-6 subunits) and monomeric γ-crystallin. Since lens proteins have very long half-lives, they undergo numerous post-translational modifications including racemization, isomerization, deamidation, oxidation, glycation, and truncation, which may decrease crystallin solubility and ultimately cause cataract formation. Racemization and isomerization of aspartyl (Asp) residues have been detected only in polymeric α- and oligomeric β-crystallin, while the situation in monomeric γ-crystallin has not been studied. Here, we investigated the racemization and isomerization of Asp in the γ-crystallin fraction of elderly donors. The results show that Asp residues of γS-, γD- and γC-crystallins were not racemized and isomerized. However, strikingly, we found that a portion of αB-crystallin and βA3-crystallin moved to the lower molecular weight fraction which is the same size of γ-crystallin. In those fractions, Asp-96 of αB-crystallin and Asp-37 of βA3-crystallin were highly inverted, which do not occur in the native lens higher molecular weight fraction. Our results indicate the possibility that the inversion of Asp residues may induce dissociation of αB- and βA3-crystallins from the polymeric and oligomeric states. This is the first report that stereoinversion of amino acids disturbs lens protein assembly in aged human lens. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Crystalline Bioceramic Materials

    Directory of Open Access Journals (Sweden)

    de Aza, P. N.

    2005-06-01

    Full Text Available A strong interest in the use of ceramics for biomedical engineering applications developed in the late 1960´s. Used initially as alternatives to metallic materials in order to increase the biocompatibility of implants, bioceramics have become a diverse class of biomaterials, presently including three basic types: relatively bioinert ceramics; bioactive or surface reactive bioceramics and bioresorbable ceramics. This review will only refer to bioceramics “sensus stricto”, it is to say, those ceramic materials constituted for nonmetallic inorganic compounds, crystallines and consolidated by thermal treatments of powders to high temperatures. Leaving bioglasses, glass-ceramics and biocements apart, since, although all of them are obtained by thermal treatments to high temperatures, the first are amorphous, the second are obtained by desvitrification of a glass and in them vitreous phase normally prevails on the crystalline phases and the third are consolidated by means of a hydraulic or chemical reaction to room temperature. A review of the composition, physiochemical properties and biological behaviour of the principal types of crystalline bioceramics is given, based on the literature data and on the own experience of the authors.

    A finales de los años sesenta se despertó un gran interés por el uso de los materiales cerámicos para aplicaciones biomédicas. Inicialmente utilizados como una alternativa a los materiales metálicos, con el propósito de incrementar la biocompatibilidad de los implantes, las biocerámicas se han convertido en una clase diversa de biomateriales, incluyendo actualmente tres tipos: cerámicas cuasi inertes; cerámicas bioactivas o reactivas superficialmente y cerámicas reabsorbibles o biodegradables. En la presente revisión se hace referencia a las biocerámicas en sentido estricto, es decir, a aquellos materiales constitutitos por compuestos inorgánicos no metálicos, cristalinos y consolidados

  20. Gamma-irradiation effects to posttranslational modification and chaperon function of bovine α-crystalline

    International Nuclear Information System (INIS)

    Hiroki, K; Matsumoto, S.; Awakura, M.; Fujii, N.

    2001-01-01

    The formation of D-asparate (D-Asp) in αA-crystallin of the aged human eye and the cataract crystalline lens has been reported. Crystalline lens keeps the transparency by forming α-crystallin which consists of a high order association of αA-and αB-crystallin. Bovine α-crystallin for investigating a chaperone function which protects the crystalline lens from getting to opaque or disordered agglutination with heat or light, is irradiated by gamma-ray (Co-60) at 0, 1, 2, 3, and 4 kGy, respectively. The irradiated bovine α-crystallin are analyzed with electrophoresis, gel permeation chromatograph, and UV absorption spectrometer for checking on the agglutination and the isomerization of macromolecules. Oxidation of methionine residues (Met-1) and isomerization of asparagine residues (Asp-151) in the αA-crystallin are ascertained in molecular levels with reversed phase liquid chromatography. The Met-1 oxidation and the Asp-151 isomerization depend on gamma-irradiation doses. It is thought that OH radical and H radical in water generated by the irradiation lead to the oxidation and the isomerization. Stereoinversion in the α-crystallin following to such a chemical change are considered to lead to the agglutination of polymer and the reduction of chaperon function. (M. Suetake)

  1. Homogeneous crystal nucleation in polymers.

    Science.gov (United States)

    Schick, C; Androsch, R; Schmelzer, J W P

    2017-11-15

    The pathway of crystal nucleation significantly influences the structure and properties of semi-crystalline polymers. Crystal nucleation is normally heterogeneous at low supercooling, and homogeneous at high supercooling, of the polymer melt. Homogeneous nucleation in bulk polymers has been, so far, hardly accessible experimentally, and was even doubted to occur at all. This topical review summarizes experimental findings on homogeneous crystal nucleation in polymers. Recently developed fast scanning calorimetry, with cooling and heating rates up to 10 6 K s -1 , allows for detailed investigations of nucleation near and even below the glass transition temperature, including analysis of nuclei stability. As for other materials, the maximum homogeneous nucleation rate for polymers is located close to the glass transition temperature. In the experiments discussed here, it is shown that polymer nucleation is homogeneous at such temperatures. Homogeneous nucleation in polymers is discussed in the framework of the classical nucleation theory. The majority of our observations are consistent with the theory. The discrepancies may guide further research, particularly experiments to progress theoretical development. Progress in the understanding of homogeneous nucleation is much needed, since most of the modelling approaches dealing with polymer crystallization exclusively consider homogeneous nucleation. This is also the basis for advancing theoretical approaches to the much more complex phenomena governing heterogeneous nucleation.

  2. Enhancing the piezoelectric properties of flexible hybrid AlN materials using semi-crystalline parylene

    Science.gov (United States)

    Jackson, Nathan; Mathewson, Alan

    2017-04-01

    Flexible piezoelectric materials are desired for numerous applications including biomedical, wearable, and flexible electronics. However, most flexible piezoelectric materials are not compatible with CMOS fabrication technology, which is desired for most MEMS applications. This paper reports on the development of a hybrid flexible piezoelectric material consisting of aluminium nitride (AlN) and a semi-crystalline polymer substrate. Various types of semi-crystalline parylene and polyimide materials were investigated as the polymer substrate. The crystallinity and surfaces of the polymer substrates were modified by micro-roughening and annealing in order to determine the effects on the AlN quality. The AlN crystallinity and piezoelectric properties decreased when the polymer surfaces were treated with O2 plasma. However, increasing the crystallinity of the parylene substrate prior to deposition of AlN caused enhanced c-axis (002) AlN crystallinity and piezoelectric response of the AlN. Piezoelectric properties of 200 °C annealed parylene-N substrate resulted in an AlN d 33 value of 4.87 pm V-1 compared to 2.17 pm V-1 for AlN on polyimide and 4.0 pm V-1 for unannealed AlN/parylene-N. The electrical response measurements to an applied force demonstrated that the parylene/AlN hybrid material had higher V pp (0.918 V) than commercial flexible piezoelectric material (PVDF) (V pp 0.36 V). The results in this paper demonstrate that the piezoelectric properties of a flexible AlN hybrid material can be enhanced by increasing the crystallinity of the polymer substrate, and the enhanced properties can function better than previous flexible piezoelectrics.

  3. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  4. Crystallinity of polyethylene in uni-axial extensional flow

    DEFF Research Database (Denmark)

    Wingstrand, Sara Lindeblad; van Drongelen, Martin; Mortensen, Kell

    Flow history of polymer melts in processing greatly influences the crystallinity and hence the solid properties of the final material. A wide range of polymer processes involve extensional flows e.g. fiber spinning, blow moulding etc. However, due to instrumental difficulties, experimental studies...... on polymer crystallization in controlled uniaxial extension are quite rare compared to studies of crystallization in shear. Inherently uniaxial extensional flows are strong and simple relative to shear flows, in the sense that chain stretch is easily obtained and that the molecules experience no tumbling...... such that crystallization from a stretched state can take place. In this work we explore this feature in the attempt to link the nonlinear extensional rheology to the final morphology. We investigate polyethylenes (PE) of various chain architectures and observe that, even for complex architectures like long chain branched...

  5. CLASSIFICATION OF BIODEGRADABLE POLYMERS

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2015-01-01

    Full Text Available The executed investigations have made it possible to ascertain that a morphological structure of starch granules mainly determine technological peculiarities of starch isolation from raw material, its modification and its later use. Morphological structure of starch granules primarily depends on type of plant starch-containing raw material which has been used for its isolation. Class of raw material exerts a strong impact on the shape and size of the granules. Linear “light” amylose chains and “heavy” amylopectin branch chains form a starch granule ultrastructure. X-ray research has proved that starch granules are characterized by presence of interlacing amorphous and crystalline regions. In this case polymer orientation using stretching of the obtained end product influences on its physical and mechanical  indices which are increasing due to polymer orientation. For the purpose of packaging orientation of polymer films can solve such important problems as significant improvement of operational properties, creation of  thermosetting film materials, improvement of qualitative indices of the recycled film.Results of the conducted research have proved the fact that it is necessary to make changes in technology in order to increase biological degradability of the recycled packaging made from polymers and improve physical and mechanical indices. In this regard film production technology presupposes usage of such substances as stark and others which are characterized by rather large presence of branch chains of molecules and interlacing amorphous and crystalline regions. Such approach makes it possible to obtain after-use package which is strong and quickly degradable by micro-organisms.

  6. Neutron transmission through crystalline Fe

    International Nuclear Information System (INIS)

    Adib, M.; Habib, N.; Kilany, M.; El-Mesiry, M.S.

    2004-01-01

    The neutron transmission through crystalline Fe has been calculated for neutron energies in the range 10 4 < E<10 eV using an additive formula. The formula permits calculation of the nuclear capture, thermal diffuse and Bragg scattering cross-section as a function of temperature and crystalline form. The obtained agreement between the calculated values and available experimental ones justifies the applicability of the used formula. A feasibility study on using poly-crystalline Fe as a cold neutron filter and a large Fe single crystal as a thermal one is given

  7. Radhard optical patchcords and packaging for satellites using liquid crystal polymers

    Science.gov (United States)

    O'Riorden, S.; Mahapatra, A.

    2017-11-01

    There are many advantages to employing fiber optics for high capacity satellite communication. However, optical cables can be susceptible to high radiation, temperature extremes and vacuum environment. Any hardware used in these systems must be rugged, durable and immune to the detrimental effects of the aforementioned conditions. Standard COTS optical fiber will darken when exposed to high levels of radiation limiting the effectiveness of the communications system. Of particular concern to satellites in GEO are energetic electrons, bursts of heavy particles due to solar storms which can cause total dose and single event effects (SEE). Conventional fiber optic cables have several issues performing in high radiation environments. Linden has patented and developed a novel cable using an extruded layer of Liquid Crystal Polymer (LCP) applied to commercially available fiber. Total dose effects are minimized by shielding with Liquid Crystal Polymer jacketing. It is a simple, inexpensive way to increase the radiation shielding and mechanical performance of cables in satellites while concomitantly providing hermeticity and thus increased fatigue factor for optical glass. • LCPs exposed to 5000 Mrad dose of gamma rays retain in excess of 90% of their mechanical properties. • LCPs exposed to 1 Mrad radiation dose with energetic protons retain almost 100% of their mechanical strength. Tensile modulus increases with exposure to the radiation. • Weight for weight the proton absorbing power of LCP is 25% better than that of aluminum. We will present experimental data on radhard optical patchcords.

  8. Synthesis and characterization of novel side-chain liquid crystalline polycarbonates, 4 - Synthesis of side-chain liquid crystalline polycarbonates with mesogenic groups having tails of different lengths

    NARCIS (Netherlands)

    Jansen, J.C.; Addink, R.; Nijenhuis, K.T.; Mijs, W.J.

    1999-01-01

    Side-chain liquid crystalline polycarbonates with alkoxyphenylbenzoate side groups, having a short spacer and tails ranging from 1 to 8 C-atoms, were synthesized. The polymers were prepared by an organo-zinc catalysed copolymerization of carbon dioxide and mesogenic 4-alkoxyphenyl

  9. A quantitative correlation between the mobility and crystallinity of photo-cross-linkable P3HT

    KAUST Repository

    Woo, Claire; Piliego, Claudia; Holcombe, Thomas W.; Toney, Michael F.; Frechet, Jean

    2012-01-01

    The performance of polymer field effect transistors (FETs) can vary by orders of magnitude by applying different processing conditions. Although it is generally believed that a higher degree of crystallinity results in a higher mobility, the correlation is not straightforward. In addition, the effect of cross-linking on polymer thin film microstructural order is relatively unknown. This study investigates the effect of thermal annealing and UV-initiated photo-cross-linking on the FET performance and microstructural order of a photo-cross-linkable P3HT derivative. Our results demonstrate that while cross-linking did not disrupt the overall crystallinity of the polymer thin film, the photo-cross-linking process likely induced doping in the semiconductor layer, leading to the absence of saturation behavior in the FET. Annealing after cross-linking slightly improved the FET performance but only minimally affected the microstructural order of the polymer film since the 3D morphology had been "locked in" during the first cross-linking step. Importantly, annealing and cross-linking simultaneously was a successful method to preserve polymer crystallinity while also achieving effective cross-linking. Using newly developed quantitative X-ray analysis techniques, our study established a quantitative correlation between FET charge mobility and thin film crystallinity. © 2012 American Chemical Society.

  10. A quantitative correlation between the mobility and crystallinity of photo-cross-linkable P3HT

    KAUST Repository

    Woo, Claire

    2012-04-10

    The performance of polymer field effect transistors (FETs) can vary by orders of magnitude by applying different processing conditions. Although it is generally believed that a higher degree of crystallinity results in a higher mobility, the correlation is not straightforward. In addition, the effect of cross-linking on polymer thin film microstructural order is relatively unknown. This study investigates the effect of thermal annealing and UV-initiated photo-cross-linking on the FET performance and microstructural order of a photo-cross-linkable P3HT derivative. Our results demonstrate that while cross-linking did not disrupt the overall crystallinity of the polymer thin film, the photo-cross-linking process likely induced doping in the semiconductor layer, leading to the absence of saturation behavior in the FET. Annealing after cross-linking slightly improved the FET performance but only minimally affected the microstructural order of the polymer film since the 3D morphology had been "locked in" during the first cross-linking step. Importantly, annealing and cross-linking simultaneously was a successful method to preserve polymer crystallinity while also achieving effective cross-linking. Using newly developed quantitative X-ray analysis techniques, our study established a quantitative correlation between FET charge mobility and thin film crystallinity. © 2012 American Chemical Society.

  11. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  12. Photorefractive polymers

    NARCIS (Netherlands)

    Bolink, Hendrik Jan; Hadziioannou, G

    1997-01-01

    This thesis describes the synthesis and properties of photorefractive polymers. Photorefractive polymers are materials in which the refractive index can be varied by the interaction with light. Unlike in numerous other photosensitive materials, in photorefractive materials this occurs via

  13. Liquid crystal polymers: evidence of hairpin defects in nematic main chains, comparison with side chain polymers

    Science.gov (United States)

    Li, M. H.; Brûlet, A.; Keller, P.; Cotton, J. P.

    1996-09-01

    This article describes the conformation of two species of liquid crystalline polymers as revealed by small angle neutron scattering. The results obtained with side chain polymers are recalled. The procedure used to analyze the scattering data of main chains in the nematic phase is reported in this paper. It permits a demonstration of the existence of hairpins. Comparison of both polymer species shows that in the isotropic phase, the two polymers adopt a random coil conformation. In the nematic phase, the conformations are very different; the side chains behave as a melt of penetrable random coils whereas the main chains behave as a nematic phase of non penetrable cylinders.

  14. Polymer Brushes

    NARCIS (Netherlands)

    Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.

    2010-01-01

    A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

  15. A constitutive law for degrading bioresorbable polymers.

    Science.gov (United States)

    Samami, Hassan; Pan, Jingzhe

    2016-06-01

    This paper presents a constitutive law that predicts the changes in elastic moduli, Poisson's ratio and ultimate tensile strength of bioresorbable polymers due to biodegradation. During biodegradation, long polymer chains are cleaved by hydrolysis reaction. For semi-crystalline polymers, the chain scissions also lead to crystallisation. Treating each scission as a cavity and each new crystal as a solid inclusion, a degrading semi-crystalline polymer can be modelled as a continuum solid containing randomly distributed cavities and crystal inclusions. The effective elastic properties of a degrading polymer are calculated using existing theories for such solid and the tensile strength of the degrading polymer is predicted using scaling relations that were developed for porous materials. The theoretical model for elastic properties and the scaling law for strength form a complete constitutive relation for the degrading polymers. It is shown that the constitutive law can capture the trend of the experimental data in the literature for a range of biodegradable polymers fairly well. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Characterisation of gamma-irradiated crystalline polymer: Pt. 3

    International Nuclear Information System (INIS)

    Jinhua Feng; Lihua Zhang; Donglin Chen

    1991-01-01

    Thermal behaviour of γ-irradiated plain PA1010 containing different amounts of difunctional cross-linking agent BMI was investigated. In DSC endo- and exotherm, it was found that during irradiation the presence of BMI markedly changes the melting and crystallisation characteristics of PA1010. A supposition that the network of BMI-containing specimens is rather loose in structure was proposed to explain the discrepancy in thermal behaviour between these two kinds of specimens. The supposition was further ascertained by the less brittleness in mechanical property of specimens containing BMI. Besides, the complexity of the thermal behaviour of γ-irradiated PA1010 was discussed and attributed mainly to the increase in σ e , the fold surface free energy of chain fold crystals. (author)

  17. Microstructure of Amorphous and Semi-Crystalline Polymers.

    Science.gov (United States)

    1981-06-07

    in IFigure 1. Again. nf evidence ofan ii( hilar featir’s is seen and the comnbinaion of the bright-field and dark-field micrographs provides strfng...S. Y’. Yeh. (’re v1c". Aacrm ,l.m I 1rcm. I, 17311972). 5. S. Krinim and A. V. Tabo sky. Textile Res. J. 21, 805 (1951). 6. A. Bij rnhatig

  18. (Meth)acrylate liquid crystalline polymers for membrane applications

    Czech Academy of Sciences Publication Activity Database

    Rabie, F.; Sedláková, Zdeňka; Sheth, S.; Marand, E.; Martin, S. M.; Poláková, Lenka

    2015-01-01

    Roč. 132, č. 43 (2015), 42694_1-42694_8 ISSN 0021-8995 Institutional support: RVO:61389013 Keywords : copolymers * liquid crystals * membranes Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.866, year: 2015

  19. LIQUID CRYSTALLINE POLYMERS FROM VANILLIC ACID: SYNTHESIS, PROPERTIES, AND APPLICATIONS.

    NARCIS (Netherlands)

    Wilsens, Karel

    2017-01-01

    Thermotropic polyesters are an important class of materials for high erformance applications. Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compression-molded

  20. Hydrodynamics of isotropic and liquid crystalline active polymer solutions.

    Science.gov (United States)

    Ahmadi, Aphrodite; Marchetti, M C; Liverpool, T B

    2006-12-01

    We describe the large-scale collective behavior of solutions of polar biofilaments and stationary and mobile crosslinkers. Both mobile and stationary crosslinkers induce filament alignment promoting either polar or nematic order. In addition, mobile crosslinkers, such as clusters of motor proteins, exchange forces and torques among the filaments and render the homogeneous states unstable via filament bundling. We start from a Smoluchowski equation for rigid filaments in solutions, where pairwise crosslink-mediated interactions among the filaments yield translational and rotational currents. The large-scale properties of the system are described in terms of continuum equations for filament and motor densities, polarization, and alignment tensor obtained by coarse-graining the Smoluchovski equation. The possible homogeneous and inhomogeneous states of the systems are obtained as stable solutions of the dynamical equations and are characterized in terms of experimentally accessible parameters. We make contact with work by other authors and show that our model allows for an estimate of the various parameters in the hydrodynamic equations in terms of physical properties of the crosslinkers.

  1. Modification of the twist angle in chiral nematic polymer films by photoisomerization of the chiral dopant

    NARCIS (Netherlands)

    Witte, van de P.; Neuteboom, E.E.; Brehmer, M.; Lub, Johan

    1999-01-01

    A method for the production of polarization sensitive recordings in liquid crystalline polymers is presented. The system is based on local modification of the twist angle of chiral nematic polymer films. The twist angle of the polymer film is varied by modifying the chemical structure of the chiral

  2. The effect of modified ijuk fibers to crystallinity of polypropylene composite

    Science.gov (United States)

    Prabowo, I.; Nur Pratama, J.; Chalid, M.

    2017-07-01

    Nowadays, plastics becomes concern associated with its degradation and environmental issues. It has led studies to develop an environmental-friendly material. To minimize the impact of those problems, recently the usage of natural fibers as a filler are introduced because of biodegradability and availability. The promising natural fiber is “ijuk” fiber from Arenga pinnata plant as a filler and polypropylene (PP) polymer as a matrix. Unfortunately, the natural fibers and polymers have the different properties on which polymers are polar while natural fibers are non-polar so that reducing the compatibility and resulting the poor crystallinity. To enhance the compatibility and crystallinity, ijuk fibers were prepared by multistage treatments including alkalinization with 5 and 10% sodium hydroxide (NaOH), oxidation with 3 and 6% sodium hypochlorite (NaClO) and hydrolysis with 20% sulphuric acid (H2SO4) in sequences. The purposes of multistage treatments are to remove the components such as lignin, wax, hemicellulose, to cause an oxidative fragmentation of remaining lignin and to annihilate the amorphous parts respectively. Fourier-Transform Infrared (FTIR) confirms the compatibility meanwhile Differential Scanning Calorimetry (DSC) reveals the crystallinity and Scanning Electron Microscope (SEM) displays surface morphology of polypropylene. The experiments were revealing that the effects of “ijuk” fibers by the multistage treatments of 5 and 10% NaOH resulting the crystallinity of polypropylene around 31.2 and 27.64% respectively compared to the crystallinity before adding the “ijuk” fibers for 16.8%. It indicates that the entire treatments increasing the compatibility and crystallinity of polypropylene. In addition, the use of 5% NaOH offers the better crystallinity than non-treated polypropylene. The experiments conclude that by adding alkalinized “ijuk” fibers of multistage treatments can increase the compatibility and crystallinity of polypropylene.

  3. Elaboration of submicron structures on PEEK polymer by femtosecond laser

    International Nuclear Information System (INIS)

    Hammouti, S.; Beaugiraud, B.; Salvia, M.; Mauclair, C.; Pascale-Hamri, A.; Benayoun, S.; Valette, S.

    2015-01-01

    Highlights: • We compare PEEK polymer under two crystalline forms: semi-crystalline and amorphous. • We assess topographical modifications of surface morphologies after femtosecond laser irradiation. • At low laser energy regime, there is an influence of the crystallinity rate on topographical features of surface morphologies. • At high laser energy regime, the contribution of the crystallinity tends to disappear. - Abstract: In this work, laser parameters initiating the emergence of periodic structures, so-called ripples on poly (ether ether ketone) (PEEK) surfaces, are investigated. PEEK was used in its semi-crystalline and amorphous forms. Polymer surfaces were treated locally by performing a matrix of laser impacts to highlight the influence of the crystallinity in ultrashort laser interaction. Different surface morphologies or ripples were analyzed by atomic force microscopy and optical interferometry. A map of the presence of these different morphologies according to the laser fluence and the number of pulses was established. Analysis by optical interferometry was carried out and led to the calculations of ablation efficiency. Some significant differences were demonstrated between amorphous and semi-crystalline surfaces. This work revealed topographical information on the local behavior of the irradiated material. Finally, the crystallinity rate of polymer surface seems to be a determinant factor for the periodic nanostructured appearance

  4. Elaboration of submicron structures on PEEK polymer by femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Hammouti, S., E-mail: sabrina.hammouti@ec-lyon.fr [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Beaugiraud, B.; Salvia, M. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Mauclair, C. [LaHC, Université Jean Monnet, 18 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); Pascale-Hamri, A. [MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); Benayoun, S. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Valette, S. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France)

    2015-02-01

    Highlights: • We compare PEEK polymer under two crystalline forms: semi-crystalline and amorphous. • We assess topographical modifications of surface morphologies after femtosecond laser irradiation. • At low laser energy regime, there is an influence of the crystallinity rate on topographical features of surface morphologies. • At high laser energy regime, the contribution of the crystallinity tends to disappear. - Abstract: In this work, laser parameters initiating the emergence of periodic structures, so-called ripples on poly (ether ether ketone) (PEEK) surfaces, are investigated. PEEK was used in its semi-crystalline and amorphous forms. Polymer surfaces were treated locally by performing a matrix of laser impacts to highlight the influence of the crystallinity in ultrashort laser interaction. Different surface morphologies or ripples were analyzed by atomic force microscopy and optical interferometry. A map of the presence of these different morphologies according to the laser fluence and the number of pulses was established. Analysis by optical interferometry was carried out and led to the calculations of ablation efficiency. Some significant differences were demonstrated between amorphous and semi-crystalline surfaces. This work revealed topographical information on the local behavior of the irradiated material. Finally, the crystallinity rate of polymer surface seems to be a determinant factor for the periodic nanostructured appearance.

  5. The make up of crystalline bedrock - crystalline body and blocks

    International Nuclear Information System (INIS)

    Huber, M.; Huber, A.

    1986-01-01

    Statements of a geological nature can be made on the basis of investigations of the bedrock exposed in southern Black Forest and these can, in the form of prognoses, be applied to the crystalline Basement of northern Switzerland. Such statements relate to the average proportions of the main lithological groups at the bedrock surface and the surface area of the granite body. Some of the prognoses can be compared and checked with the results from the deep drilling programme in northern Switzerland. Further, analogical interferences from the situation in the southern Black Forest allow predictions to be made on the anticipated block structure of the crystalline Basement. (author)

  6. neutron transmission through crystalline materials

    International Nuclear Information System (INIS)

    El Mesiry, M.S.

    2011-01-01

    The aim of the present work is to study the neutron transmission through crystalline materials. Therefore a study of pyrolytic graphite (PG) as a highly efficient selective thermal neutron filter and Iron single crystal as a whole one, as well as the applicability of using their polycrystalline powders as a selective cold neutron filters is given. Moreover, the use of PG and iron single crystal as an efficient neutron monochromator is also investigated. An additive formula is given which allows calculating the contribution of the total neutron cross-section including the Bragg scattering from different )(hkl planes to the neutron transmission through crystalline iron and graphite. The formula takes into account their crystalline form. A computer CFe program was developed in order to provide the required calculations for both poly- and single-crystalline iron. The validity of the CFe program was approved from the comparison of the calculated iron cross-section data with the available experimental ones. The CFe program was also adapted to calculate the reflectivity from iron single crystal when it used as a neutron monochromator The computer package GRAPHITE, developed in Neutron Physics laboratory, Nuclear Research Center, has been used in order to provide the required calculations for crystalline graphite in the neutron energy range from 0.1 meV to 10 eV. A Mono-PG code was added to the computer package GRAPHITE in order to calculate the reflectivity from PG crystal when it used as a neutron monochromator.

  7. Diverse topics in crystalline beams

    International Nuclear Information System (INIS)

    Wei, Jie; Draeseke, A.; Sessler, A.M.; Li, Xiao-Ping

    1995-01-01

    Equations of motion are presented, appropriate to interacting charged particles of diverse charge and mass, subject to the external forces produced by various kinds of magnetic fields and radio-frequency (rf) electric fields in storage rings. These equations are employed in the molecular dynamics simulations to study the properties of crystalline beams. The two necessary conditions for the formation and maintenance of crystalline beams are summarized. The transition from ID to 2D, and from 2D to 3D is explored, and the scaling behavior of the heating rates is discussed especially in the high temperature limit. The effectiveness of various cooling techniques in achieving crystalline states has been investigated. Crystalline beams made of two different species of ions via sympathetic cooling are presented, as well as circulating ''crystal balls'' bunched in all directions by magnetic focusing and rf field. By numerically reconstructing the original experimental conditions of the NAP-M ring, it is found that only at extremely low beam intensities, outside of the range of the original measurement, proton particles can form occasionally-passing disks. The proposed New ASTRID ring is shown to be suitable for the formation and maintenance of crystalline beams of all dimensions

  8. The influence of polymerization rate on conductivity and crystallinity of electropolymerized polypyrrole

    DEFF Research Database (Denmark)

    Dyreklev, P.; Granström, M.; Inganäs, O.

    1996-01-01

    We report studies on electronic conductivity and crystallinity in electropolymerized polypyrrole. Different growth rates during electropolymerization strongly influence and determine structural and electronic properties. Polymer films grown using low current density show higher electronic conduct...... a different coupling route in the polymerization, induced by the lower current density. Copyright (C) 1996 Elsevier Science Ltd....

  9. Controlling the morphology of side chain liquid crystalline block copolymer thin films through variations in liquid crystalline content.

    Science.gov (United States)

    Verploegen, Eric; Zhang, Tejia; Jung, Yeon Sik; Ross, Caroline; Hammond, Paula T

    2008-10-01

    In this paper, we describe methods for manipulating the morphology of side-chain liquid crystalline block copolymers through variations in the liquid crystalline content. By systematically controlling the covalent attachment of side chain liquid crystals to a block copolymer (BCP) backbone, the morphology of both the liquid crystalline (LC) mesophase and the phase-segregated BCP microstructures can be precisely manipulated. Increases in LC functionalization lead to stronger preferences for the anchoring of the LC mesophase relative to the substrate and the intermaterial dividing surface. By manipulating the strength of these interactions, the arrangement and ordering of the ultrathin film block copolymer nanostructures can be controlled, yielding a range of morphologies that includes perpendicular and parallel cylinders, as well as both perpendicular and parallel lamellae. Additionally, we demonstrate the utilization of selective etching to create a nanoporous liquid crystalline polymer thin film. The unique control over the orientation and order of the self-assembled morphologies with respect to the substrate will allow for the custom design of thin films for specific nanopatterning applications without manipulation of the surface chemistry or the application of external fields.

  10. Thermal characterization of semiconducting polymer bulk heterojunctions

    Science.gov (United States)

    Remy, Roddel A.

    Polymer semiconductors are intriguing due to their potential use in flexible electronics. Poly (3-hexylthiophene) (P3HT)--a very common polymer in this field--is semicrystalline and it is known that crystalline P3HT has a higher hole mobility than amorphous P3HT. Quantifying each fraction in the bulk and thin film states is therefore crucial to understanding its performance in transistor and other applications. In polymer solar cells, it acts as an electron donor and is typically mixed with the nanoparticle-like molecule, phenyl-C61-butyric acid methyl ester (PCBM)--an electron acceptor--in a thin film morphology termed a bulk heterojunction (BHJ). The structural hierarchy within the bulk heterojunction is complicated and its characterization, with a focus on P3HT morphology, is the topic of this dissertation. Calorimetry can play an important role in the elucidation of P3HT morphology with quantitative analysis of the crystalline and amorphous fractions present in the material. This was demonstrated by employing differential scanning calorimetry (DSC) to obtain the enthalpy of fusion of 100% crystalline P3HT (42.9 J/g) using oligomeric P3HT measurements. The more sensitive temperature modulated DSC (TMDSC) was then used to examine the glass transition of P3HT and the crystalline, mobile amorphous and rigid amorphous phases were quantified. The presence of these phases can play a large role in understanding the charge transfer process in polymer semiconductors. BHJ thin films of 50 wt.% PCBM were then analyzed and a polymer crystallinity of 30% was found after thermal annealing from initially non-crystalline polymer material. With assistance from previously acquired small angle neutron scattering data, a thorough analysis of the entire BHJ morphology was accomplished. A surprisingly large rigid amorphous polymer phase is present in the BHJ which could be located at the P3HT/PCBM interface, affecting charge transfer. Finally, interlayer diffusion of PCBM was

  11. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  12. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  13. Polymer chemistry (revised edition)

    International Nuclear Information System (INIS)

    Kim, Jae Mum

    1987-02-01

    This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

  14. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-01-01

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [ 3 H]NaBH 4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  15. gamma. -relaxation process in crystallizable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mindiyarov, Kh G; Zelenev, Yu V; Bartenev, G M [Birskij Gosudarstvennyj Pedagogicheskij Inst. (USSR)

    1975-07-01

    In the present paper, with the aid of radiothermoluminescence technique ..gamma..-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to ..gamma..-rays of Co/sup 60/ at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the ..cap alpha.. - ..gamma..-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP ..cap alpha..-maximum may be absent. Dependence has been studied of the luminescence intensity in the ..cap alpha..- and ..gamma..-maxima (Isub(..cap alpha..)/Isub(..gamma..)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(..gamma..)re of crystallinity degree.

  16. Generic Crystalline Disposal Reference Case

    Energy Technology Data Exchange (ETDEWEB)

    Painter, Scott Leroy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harp, Dylan Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Perry, Frank Vinton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-20

    A generic reference case for disposal of spent nuclear fuel and high-level radioactive waste in crystalline rock is outlined. The generic cases are intended to support development of disposal system modeling capability by establishing relevant baseline conditions and parameters. Establishment of a generic reference case requires that the emplacement concept, waste inventory, waste form, waste package, backfill/buffer properties, EBS failure scenarios, host rock properties, and biosphere be specified. The focus in this report is on those elements that are unique to crystalline disposal, especially the geosphere representation. Three emplacement concepts are suggested for further analyses: a waste packages containing 4 PWR assemblies emplaced in boreholes in the floors of tunnels (KBS-3 concept), a 12-assembly waste package emplaced in tunnels, and a 32-assembly dual purpose canister emplaced in tunnels. In addition, three failure scenarios were suggested for future use: a nominal scenario involving corrosion of the waste package in the tunnel emplacement concepts, a manufacturing defect scenario applicable to the KBS-3 concept, and a disruptive glaciation scenario applicable to both emplacement concepts. The computational approaches required to analyze EBS failure and transport processes in a crystalline rock repository are similar to those of argillite/shale, with the most significant difference being that the EBS in a crystalline rock repository will likely experience highly heterogeneous flow rates, which should be represented in the model. The computational approaches required to analyze radionuclide transport in the natural system are very different because of the highly channelized nature of fracture flow. Computational workflows tailored to crystalline rock based on discrete transport pathways extracted from discrete fracture network models are recommended.

  17. RoxB Is a Novel Type of Rubber Oxygenase That Combines Properties of Rubber Oxygenase RoxA and Latex Clearing Protein (Lcp).

    Science.gov (United States)

    Birke, Jakob; Röther, Wolf; Jendrossek, Dieter

    2017-07-15

    Only two types of rubber oxygenases, rubber oxygenase (RoxA) and latex clearing protein (Lcp), have been described so far. RoxA proteins (RoxAs) are c -type cytochromes of ≈70 kDa produced by Gram-negative rubber-degrading bacteria, and they cleave polyisoprene into 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD), a C 15 oligo-isoprenoid, as the major end product. Lcps are common among Gram-positive rubber degraders and do not share amino acid sequence similarities with RoxAs. Furthermore, Lcps have much smaller molecular masses (≈40 kDa), are b -type cytochromes, and cleave polyisoprene to a mixture of C 20 , C 25 , C 30 , and higher oligo-isoprenoids as end products. In this article, we purified a new type of rubber oxygenase, RoxB Xsp (RoxB of Xanthomonas sp. strain 35Y). RoxB Xsp is distantly related to RoxAs and resembles RoxAs with respect to molecular mass (70.3 kDa for mature protein) and cofactor content (2 c -type hemes). However, RoxB Xsp differs from all currently known RoxAs in having a distinctive product spectrum of C 20 , C 25 , C 30 , and higher oligo-isoprenoids that has been observed only for Lcps so far. Purified RoxB Xsp revealed the highest specific activity of 4.5 U/mg (at 23°C) of all currently known rubber oxygenases and exerts a synergistic effect on the efficiency of polyisoprene cleavage by RoxA Xsp RoxB homologs were identified in several other Gram-negative rubber-degrading species, pointing to a prominent function of RoxB for the biodegradation of rubber in Gram-negative bacteria. IMPORTANCE The enzymatic cleavage of rubber (polyisoprene) is of high environmental importance given that enormous amounts of rubber waste materials are permanently released (e.g., by abrasion of tires). Research from the last decade has discovered rubber oxygenase A, RoxA, and latex clearing protein (Lcp) as being responsible for the primary enzymatic attack on the hydrophobic and water-insoluble biopolymer poly( cis -1,4-isoprene) in Gram

  18. A CLINICAL STUDY OF PROXIMAL FEMUR LOCKING COMPRESSION PLATE (LCP - PF IN THE MANAGEMENT OF COMMUNITED INTERTROCHANTERIC AND SUBTROCHANTERIC FRACTURES OF THE FEMUR

    Directory of Open Access Journals (Sweden)

    Hari Babu

    2015-10-01

    Full Text Available Fractures of proximal femur and hip are relatively common injuries in elderly individuals . The incidence of peritrochanteric and intertrochanteric fracture is also increasing among young population, who sustain high energy trauma Rigid Internal fixation and early mobilization has been the standard method of treatment. A combination of orthopaedic surgery and early postoperative physiotherapy and ambulation is the best approach. The overall goal in the treatment of hip fractures is to return the patient to pre - morbid level of function. AIMS & OBJECTIVE : To analyse the anatomical and f unctional outcome of the treatment with LCP - Proximal femur. METHODOLOGY : The present study consists of 12 adult patients of peritrochanteric factures of femur satisfying the inclusion criteria , treated with Proximal Femoral Locking Compression Plate at S. V. R. R . Govt . General Hospital, Tirupati during the period of nov 2013 to Oct 2015. INCLUSION CRITERIA : Age >18years , comminuted trochanteric and sub trochanteric fractures , Signed written informed consent . EXCLUSION CRITERIA: Inter trochanteric fractures involving piriformis fossa , Compound fractures . Pathological fractures . Any displacement of a femoral neck fracture . A ssociated malignancy. RESULTS : Average age incidence in the present study was 62.7 years. , Predominantly males (75% were affected. , Most cases occurred after a fall 10 (50% cases which was statistically significant , Right side involvement was more common. , Average post - operative stay was 13.5 days. , Out of the 12 cases, evaluated using Salvati - Wilson scoring : 3 cases (25% had good, 8 cases (66.67% fair, 1 case (8.33% had poor score , Average weight bearing time was14.5 weeks , Average union rate was 19.45 weeks.

  19. Chain confinement, phase transitions, and lamellar structure in semicrystalline polymers, polymer blends and polymer nanocomposites

    Science.gov (United States)

    Chen, Huipeng

    Recent studies suggest that there are three phase fractions in semicrystalline polymers, the crystalline, the mobile amorphous and the rigid amorphous phases. Due to the distinct properties of the rigid amorphous fraction, RAF, it has been investigated for more than twenty years. In this thesis, a general method using quasi-isothermal temperature-modulated differential scaning calorimetry, DSC, is provided for the first time to obtain the temperature dependent RAF and the other two fractions, crystalline fraction and mobile amorphous fraction, MAF. For poly(ethylene terephthalate), PET, our results show RAF was vitrified during quasi-isothermal cooling after crystallization had been completed and became totally devitrified during quasi-isothermal heating before the start of melting. Several years after people initially discovered the existence of RAF, another issue arose relating to the physical location of RAF and mobile amorphous fraction, MAF, within a lamellar stack model. Two very different models to describe the location of RAF were proposed. In the Heterogeneous Stack Model, HET, RAF is located outside the lamellar stacks. In the Homogeneous Stack Model, HSM, RAF was located inside the lamellar stacks. To determine the lamellar structure of semicrystalline polymers comprising three phase, a general method is given in this thesis by using a combination of the DSC and small angle X-ray scattering, SAXS techniques. It has been applied to Nylon 6, isotactic polystyrene, iPS, and PET. It was found for all of these materials, the HSM model is correct to describe the lamellar structure. In addition to the determination of lamellar structures, this method can also provide the exact fraction of MAF inside and outside lamellar stacks for binary polymer blends. For binary polymer blends, MAF, normally is located partially inside and partially outside the lamellar stacks. However, the quantification of the MAF inside and outside the lamellar stacks has now been provided

  20. Self-healing polymers

    Science.gov (United States)

    Klein, Daniel J. (Inventor)

    2011-01-01

    A three dimensional structure fabricated from a self-healing polymeric material, comprising poly(ester amides) obtained from ethylene glycol, azelaic acid and 1,1-aminoundecanoic acid, wherein polymeric material has a melt index above 2.5 g/10 min. as determined by ASTM D1238 at 190.degree. C. and 2.16kg, impact resistance and ductility sufficient to resist cracking and brittle fracture upon impact by a 9 mm bullet fired at a temperature of about 29.degree. C. at subsonic speed in a range from about 800 feet/sec to about 1000 feet/sec. It has been determined that the important factors necessary for self-healing behavior of polymers include sufficient impact strength, control of the degree of crystallinity, low melting point and the ability to instantly melt at impacted area.

  1. On the relevance of the micromechanics approach for predicting the linear viscoelastic behavior of semi-crystalline poly(ethylene)terephtalates (PET)

    International Nuclear Information System (INIS)

    Diani, J.; Bedoui, F.; Regnier, G.

    2008-01-01

    The relevance of micromechanics modeling to the linear viscoelastic behavior of semi-crystalline polymers is studied. For this purpose, the linear viscoelastic behaviors of amorphous and semi-crystalline PETs are characterized. Then, two micromechanics modeling methods, which have been proven in a previous work to apply to the PET elastic behavior, are used to predict the viscoelastic behavior of three semi-crystalline PETs. The microstructures of the crystalline PETs are clearly defined using WAXS techniques. Since microstructures and mechanical properties of both constitutive phases (the crystalline and the amorphous) are defined, the simulations are run without adjustable parameters. Results show that the models are unable to reproduce the substantial decrease of viscosity induced by the increase of crystallinity. Unlike the real materials, for moderate crystallinity, both models show materials of viscosity nearly identical to the amorphous material

  2. Ferrofluids in liquid crystalline systems

    International Nuclear Information System (INIS)

    Figueiredo Neto, A.M.; Liebert, L.

    1989-08-01

    It is a well-known fact that intermediate or mesomorphic phase may exist between the crystalline and the isotropic liquid phases. The symmetry properties of these mesophases are intermediate between those of a crystal and a liquid. In this paper, some aspects of the use of ferrofluids in thermotropic and lyotropic systems are studied both the experimental difficulties as well as the fundamental phypical phenomena involved. (A.C.A.S.) [pt

  3. EELS from organic crystalline materials

    International Nuclear Information System (INIS)

    Brydson, R; Seabourne, C R; Hondow, N; Eddleston, M D; Jones, W

    2014-01-01

    We report the use of the electron energy loss spectroscopy (EELS) for providing light element chemical composition information from organic, crystalline pharmaceutical materials including theophylline and paracetamol and discuss how this type of data can complement transmission electron microscopy (TEM) imaging and electron diffraction when investigating polymorphism. We also discuss the potential for the extraction of bonding information using electron loss near-edge structure (ELNES)

  4. Soliton structure in crystalline acetanilide

    International Nuclear Information System (INIS)

    Eilbeck, J.C.; Lomdahl, P.S.; Scott, A.C.

    1984-01-01

    The theory of self-trapping of amide I vibrational energy in crystalline acetanilide is studied in detail. A spectrum of stationary, self-trapped (soliton) solutions is determined and tested for dynamic stability. Only those solutions for which the amide I energy is concentrated near a single molecule were found to be stable. Exciton modes were found to be unstable to decay into solitons

  5. Graphene on insulating crystalline substrates

    International Nuclear Information System (INIS)

    Akcoeltekin, S; El Kharrazi, M; Koehler, B; Lorke, A; Schleberger, M

    2009-01-01

    We show that it is possible to prepare and identify ultra-thin sheets of graphene on crystalline substrates such as SrTiO 3 , TiO 2 , Al 2 O 3 and CaF 2 by standard techniques (mechanical exfoliation, optical and atomic force microscopy). On the substrates under consideration we find a similar distribution of single layer, bilayer and few-layer graphene and graphite flakes as with conventional SiO 2 substrates. The optical contrast C of a single graphene layer on any of those substrates is determined by calculating the optical properties of a two-dimensional metallic sheet on the surface of a dielectric, which yields values between C = -1.5% (G/TiO 2 ) and C = -8.8% (G/CaF 2 ). This contrast is in reasonable agreement with experimental data and is sufficient to make identification by an optical microscope possible. The graphene layers cover the crystalline substrate in a carpet-like mode and the height of single layer graphene on any of the crystalline substrates as determined by atomic force microscopy is d SLG = 0.34 nm and thus much smaller than on SiO 2 .

  6. Biocompatibility of crystalline opal nanoparticles.

    Science.gov (United States)

    Hernández-Ortiz, Marlen; Acosta-Torres, Laura S; Hernández-Padrón, Genoveva; Mendieta, Alicia I; Bernal, Rodolfo; Cruz-Vázquez, Catalina; Castaño, Victor M

    2012-10-22

    Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal), despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm) were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT) and 5-bromo-2'-deoxyuridine (BrdU). 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells.

  7. Thermotropic liquid crystalline polyazomethine nanocomposites via in situ interlayer polymerization

    International Nuclear Information System (INIS)

    Min, Ungki; Chang, Jin-Hae

    2011-01-01

    Highlights: → Nanocomposites of polyazomethine with the organoclay C 12 -MMT were synthesized by using the in situ interlayer polymerization method. → The thermal properties of the polyazomethine hybrids increase with the addition of the organoclay up to a critical content and then decrease with further organoclay loading. → Liquid crystalline compositions with 0-9 wt% organoclay have threaded Schlieren nematic textures. - Abstract: Nanocomposites of polyazomethine (PAM) with the organoclay C 12 -MMT were synthesized by using the in situ interlayer polymerization method. The variations with organoclay content of the thermal properties, morphology, and liquid crystalline mesophases of the hybrids were determined for concentrations from 0 to 9 wt% C 12 -MMT. The thermal properties and the morphologies of the PAM nanocomposites were examined by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide angle X-ray diffractometry (XRD), transmission electron microscopy (TEM), and polarizing optical microscopy (POM). The XRD analysis and TEM micrographs show that the levels of nanosize dispersion can be controlled by varying the C 12 -MMT content. The clay particles are better dispersed in the matrix polymer at low clay contents than at high clay contents. With the exception of the glass transition temperature (T g ), the maximum enhancement in the thermal properties was found to arise at an organoclay content of 1 wt%. Further, the PAM hybrids were shown to exhibit a nematic liquid crystalline phase for organoclay contents in the range 0-9 wt%.

  8. Characterization of the polymer energy landscape in polymer:fullerene bulk heterojunctions with pure and mixed phases

    KAUST Repository

    Sweetnam, Sean

    2014-10-08

    Theoretical and experimental studies suggest that energetic offsets between the charge transport energy levels in different morphological phases of polymer:fullerene bulk heterojunctions may improve charge separation and reduce recombination in polymer solar cells (PSCs). In this work, we use cyclic voltammetry, UV-vis absorption, and ultraviolet photoelectron spectroscopy to characterize hole energy levels in the polymer phases of polymer:fullerene bulk heterojunctions. We observe an energetic offset of up to 150 meV between amorphous and crystalline polymer due to bandgap widening associated primarily with changes in polymer conjugation length. We also observe an energetic offset of up to 350 meV associated with polymer:fullerene intermolecular interactions. The first effect has been widely observed, but the second effect is not always considered despite being larger in magnitude for some systems. These energy level shifts may play a major role in PSC performance and must be thoroughly characterized for a complete understanding of PSC function.

  9. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    methods for the synthesis of polymer nanocomposites. In this article we .... ers, raw materials recovery, drug delivery and anticorrosion .... region giving rise to dose-packed absorption bands called an IR ... using quaternary ammonium salts.

  10. Development of highly porous crystalline titania photocatalysts

    Science.gov (United States)

    Marszewski, Michal

    The objectives of this dissertation are the design, synthesis, and characterization of titania materials with surface area, porosity, crystallinity and doping tailored toward photocatalytic applications. Ultimately, the research should result in a strategy allowing the synthesis of titania with all these important features. The synthetic methods investigated in this research will include: i) soft-templating, ii) hard-templating, and iii) modified precursor strategy. Soft-templating strategy uses organic templates--either block copolymers or surfactants--that under specific conditions assemble into micelles, and later, these micelles are used to template the desired material around them. The resulting organic-inorganic composite is then calcined in air to remove the organic template and recover the final material with high surface area and large pore volume. This work explores 1) synthesis of titania materials in the presence of polymer templates, and the effects of different synthetic conditions on the structure of the resulting materials. Hard-templating, in contrast to soft-templating, uses inorganic templates. The hard template is introduced during the synthesis to cast its shape onto the fabricated material and removed afterwards, when the material has formed. The final material is an inverse replica of the hard template used, typically with a well-developed mesostructure. This work explores 1) hard templating synthesis of titania materials using silica and alumina, and 2) the effects of the template amount and type. The modified precursor strategy is a novel synthetic method, developed in this research, and designed specifically to achieve titania material with high surface area, large pore volume, high crystallinity, and possibly doping. The modified precursors are prepared by reacting generic titania precursors, such as titanium isopropoxide (TIPO), with organic acids, which results in substitution of some or all alkoxide groups in TIPO structure. The goal

  11. Styrene-Based Copolymer for Polymer Membrane Modifications

    OpenAIRE

    Harsha Srivastava; Harshad Lade; Diby Paul; G. Arthanareeswaran; Ji Hyang Kweon

    2016-01-01

    Poly(vinylidene fluoride) (PVDF) was modified with a styrene-based copolymer. The crystalline behavior, phase, thermal stability, and surface morphology of the modified membranes were analyzed. The membrane surface roughness showed a strong dependence on the styrene-acrylonitrile content and was reduced to 34% for a PVDF/styrene-acrylonitrile blend membrane with a 40/60 ratio. The thermal and crystalline behavior confirmed the blend miscibility of both polymers. It was observed in X-ray diffr...

  12. The effect of the stretching of PLA extruded films on their crystallinity and gas barrier properties

    Science.gov (United States)

    Guinault, A.; Menary, G. H.; Courgneau, C.; Griffith, D.; Ducruet, V.; Miri, V.; Sollogoub, C.

    2011-05-01

    Driven by environmental concerns, new polymers based on renewable resources are arriving on the market to replace conventional polymers, obtained from petroleum, for different applications like food packaging. One of the most prominent polymers among these materials is poly(lactic acid) (PLA), a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the USA) or sugarcanes (in the rest of the world). However this polymer presents different disadvantages and especially low gas barrier properties [1]. Thermal crystallization can be used to increase its gas barrier properties but long times are necessary [2] and are not compatible with an industrial process. Another way to increase the gas barrier properties consists in stretching the film in order to increase its crystallinity and so its diffusion coefficient. We have prepared stretched PLA films with different stretch ratio and we have studied the effect of the stretching parameters on the gas barrier properties of PLA films. Finally we compared this process with the isothermal crystallization process by taking into account the crystallinity degree and the crystalline morphology.

  13. Entanglements in Conjugated Polymers

    Science.gov (United States)

    Xie, Renxuan; Lee, Youngmin; Aplan, Melissa; Caggiano, Nick; Gomez, Enrique; Colby, Ralph

    Conjugated polymers, such as poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly-((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(thiophen-5-yl)-2,1,3-benzothiadiazole]-2',2''-diyl) (PFTBT), are widely used as hole and electron transport materials in a variety of electronic devices. However, fundamental knowledge regarding chain entanglements and nematic-to-isotropic transition is still lacking and are crucial to maximize charge transport properties. A systematic melt rheology study on P3HT with various molecular weights and regio regularities was performed. We find that the entanglement molecular weight Me is 5.0 kg/mol for regiorandom P3HT, but the apparent Me for regioregular P3HT is significantly higher. The difference is postulated to arise from the presence of a nematic phase only in regioregular P3HT. Analogously, PFTBT shows a clear rheological signature of the nematic-to-isotropic transition as a reversible sharp transition at 278 C. Shearing of this nematic phase leads to anisotropic crystalline order in PFTBT. We postulate that aligning the microstructure will impact charge transport and thereby advance the field of conducting polymers. National Science Foundation.

  14. The negative piezoelectric effect of the ferroelectric polymer poly(vinylidene fluoride)

    DEFF Research Database (Denmark)

    Katsouras, Ilias; Asadi, Kamal; Li, Mengyuan

    2016-01-01

    with trifluoroethylene (P(VDF-TrFE)), which exhibit a negative longitudinal piezoelectric coefficient. Reported explanations exclusively consider contraction with applied electric field of either the crystalline or the amorphous part of these semi-crystalline polymers. To distinguish between these conflicting...

  15. Saline groundwater in crystalline bedrock

    International Nuclear Information System (INIS)

    Lampen, P.

    1992-11-01

    The State-of-art report describes research made on deep saline groundwaters and brines found in crystalline bedrock, mainly in site studies for nuclear waste disposal. The occurrence, definitions and classifications of saline groundwaters are reviewed with a special emphasis on the different theories concerning the origins of saline groundwaters. Studies of the saline groundwaters in Finland and Sweden have been reviewed more thoroughly. Also the mixing of different bodies of groundwaters, observations of the contact of saline groundwaters and permafrost, and the geochemical modelling of saline groundwaters as well as the future trends of research have been discussed. (orig.)

  16. Crystalline beams: The vertical zigzag

    International Nuclear Information System (INIS)

    Haffmans, A.F.; Maletic, D.; Ruggiero, A.G.

    1994-01-01

    This note is the continuation of our comprehensive investigation of Crystalline Beams. After having determined the equations of motion and the conditions for the formation of the simplest configuration, i.e. the string, we study the possibility of storing an intense beam of charged particles in a storage ring where they form a vertical zigzag. We define the equilibrium configuration, and examine the confinement conditions. Subsequently, we derive the transfer matrix for motion through various elements of the storage ring. Finally we investigate the stability conditions for such a beam

  17. Crystalline cerium(IV) phosphates

    International Nuclear Information System (INIS)

    Herman, R.G.; Clearfield, A.

    1976-01-01

    The ion exchange behaviour of seven crystalline cerium(IV) phosphates towards some of the alkali metal cations is described. Only two of the compounds (A and C) possess ion exchange properties in acidic solutions. Four others show some ion exchange characteristics in basic media with some of the alkali cations. Compound G does not behave as an ion exchanger in solutions of pH + , but show very little Na + uptake. Compound E undergoes ion exchange with Na + and Cs + , but not with Li+. Both Li + and Na + are sorbed by compounds A and C. The results are indicative of structures which show steric exclusion phenomena. (author)

  18. Perfluorinated polymer grafting: influence of preirradiation conditions

    International Nuclear Information System (INIS)

    Moura, E.; Somessari, E.S.R.; Silveira, C.G.; Paes, H.A.; Sousa, C.A.; Fernandes, W.; Manzoli, J.E; Geraldo, A.B.; Cardozo, P.

    2009-01-01

    The technological interest of perfluorinated polymers is related to its specific properties like low chemical reactivity and high mechanical and temperature resistance. The development of polymeric membranes for PEM fuel cell dispositives requires beyond these characteristics, a long-life time performance and low cost compared to Nafion membranes. By these material have high crystallinity, the radiation grafting indeed occurs but this process generate a low mechanical resistance aggregate. In this way, it is necessary to render the polymer with a low crystallinity or even amorphous. Generally, irradiation under polymer melt temperatures makes the crystallinity breaking and polymer crosslinking. The main objective of this work was promoting the crosslinking process into perfluorinated polymers by pre-irradiation method and to precede styrene grafting by electron beam irradiation in a second step. The experimental methodology consists in pre-irradiate perfluorinated polymers films like PTFE and PFA under high temperature (> 300 deg C) and vacuum conditions by electron beam irradiation at 5 kGy to 30 kGy doses and 2,85 kGy/s to 22,4 kGy/s dose rates. To obtain temperatures above 300 deg C, it was necessary construct a vacuum chamber with a heating system where temperature process could be follow up in real time. Some molecular alterations in polymeric matrix were analyzed by Mid-ATR-FTIR spectroscopy; macroscopic changes are verified by gravimetry. The styrene grafting onto these samples is realized by electron beam irradiation at doses between 30 and 100 kGy. These results are discussed. (author)

  19. Structure-Property Relationships of Semiconducting Polymers for Flexible and Durable Polymer Field-Effect Transistors.

    Science.gov (United States)

    Kim, Min Je; Jung, A-Ra; Lee, Myeongjae; Kim, Dongjin; Ro, Suhee; Jin, Seon-Mi; Nguyen, Hieu Dinh; Yang, Jeehye; Lee, Kyung-Koo; Lee, Eunji; Kang, Moon Sung; Kim, Hyunjung; Choi, Jong-Ho; Kim, BongSoo; Cho, Jeong Ho

    2017-11-22

    We report high-performance top-gate bottom-contact flexible polymer field-effect transistors (FETs) fabricated by flow-coating diketopyrrolopyrrole (DPP)-based and naphthalene diimide (NDI)-based polymers (P(DPP2DT-T2), P(DPP2DT-TT), P(DPP2DT-DTT), P(NDI2OD-T2), P(NDI2OD-F2T2), and P(NDI2OD-Se2)) as semiconducting channel materials. All of the polymers displayed good FET characteristics with on/off current ratios exceeding 10 7 . The highest hole mobility of 1.51 cm 2 V -1 s -1 and the highest electron mobility of 0.85 cm 2 V -1 s -1 were obtained from the P(DPP2DT-T2) and P(NDI2OD-Se2) polymer FETs, respectively. The impacts of the polymer structures on the FET performance are well-explained by the interplay between the crystallinity, the tendency of the polymer backbone to adopt an edge-on orientation, and the interconnectivity of polymer fibrils in the film state. Additionally, we demonstrated that all of the flexible polymer-based FETs were highly resistant to tensile stress, with negligible changes in their carrier mobilities and on/off ratios after a bending test. Conclusively, these high-performance, flexible, and durable FETs demonstrate the potential of semiconducting conjugated polymers for use in flexible electronic applications.

  20. Highly Crystalline and Low Bandgap Donor Polymers for Efficient Polymer Solar Cells

    Science.gov (United States)

    2012-01-01

    extraction sequentially with acetone, hexane, chloroform , and chlorobenzene for 24 h each. The chlorobenzene fraction was collected and...resistivity: 15 Ω per square) were ultrasonicated sequentially in detergent, deionized water, acetone, and iso- propyl alcohol for 10 min each. The

  1. Lateral topological crystalline insulator heterostructure

    Science.gov (United States)

    Sun, Qilong; Dai, Ying; Niu, Chengwang; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao

    2017-06-01

    The emergence of lateral heterostructures fabricated by two-dimensional building blocks brings many exciting realms in material science and device physics. Enriching available nanomaterials for creating such heterostructures and enabling the underlying new physics is highly coveted for the integration of next-generation devices. Here, we report a breakthrough in lateral heterostructure based on the monolayer square transition-metal dichalcogenides MX2 (M  =  W, X  =  S/Se) modules. Our results reveal that the MX2 lateral heterostructure (1S-MX2 LHS) can possess excellent thermal and dynamical stability. Remarkably, the highly desired two-dimensional topological crystalline insulator phase is confirmed by the calculated mirror Chern number {{n}\\text{M}}=-1 . A nontrivial band gap of 65 meV is obtained with SOC, indicating the potential for room-temperature observation and applications. The topologically protected edge states emerge at the edges of two different nanoribbons between the bulk band gap, which is consistent with the mirror Chern number. In addition, a strain-induced topological phase transition in 1S-MX2 LHS is also revealed, endowing the potential utilities in electronics and spintronics. Our predictions not only introduce new member and vitality into the studies of lateral heterostructures, but also highlight the promise of lateral heterostructure as appealing topological crystalline insulator platforms with excellent stability for future devices.

  2. Approaches for Making High Performance Polymer Materials from Commodity Polymers

    Institute of Scientific and Technical Information of China (English)

    Xu Xi

    2004-01-01

    A brief surrey of ongoing research work done for improving and enhancing the properties of commodity polymers by the author and author's colleagues is given in this paper. A series of high performance polymers and polymer nanomaterials were successfully prepared through irradiation and stress-induced reactions of polymers and hydrogen bonding. The methods proposed are viable, easy in operation, clean and efficient.1. The effect of irradiation source (UV light, electron beam, γ -ray and microwave), irradiation dose, irradiation time and atmosphere etc. on molecular structure of polyolefine during irradiation was studied. The basic rules of dominating oxidation, degradation and cross-linking reactions were mastered. Under the controlled conditions, cross-linking reactions are prevented, some oxygen containing groups are introduced on the molecular chain of polyolefine to facilitate the interface compatibility of their blends. A series of high performance polymer materials: u-HDPE/PA6,u-HDPE/CaCO3, u-iPP/STC, γ-HDPE/STC, γ-LLDPE/ATH, e-HDPE, e-LLDPE and m-HDPEfilled system were prepared (u- ultraviolet light irradiated, γ- γ-ray irradiated, e- electron beam irradiated, m- microwave irradiated)2. The effect of ultrasonic irradiation, jet and pan-milling on structure and changes in properties of polymers were studied. Imposition of critical stress on polymer chain can cause the scission of bonds to form macroradicals. The macroradicals formed in this way may recombine or react with monomer or other radicals to form linear, branched or cross-linked polymers or copolymers. About 20 kinds of block/graft copolymers have been synthesized from polymer-polymer or polymer-monomer through ultrasonic irradiation.Through jet-milling, the molecular weight of PVC is decreased somewhat, the intensity of its crystalline absorption bonds becomes indistinct. The processability, the yield strength, strength at break and elongation at break of PVC get increased quite a lot after

  3. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel; Srivastava, Samanvaya; Narayanan, Suresh; Archer, Lynden A.

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has

  4. Antimocrobial Polymer

    Science.gov (United States)

    McDonald, William F.; Huang, Zhi-Heng; Wright, Stacy C.

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  5. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  6. Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Baoxia [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Huang, Yankai [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhu, Xu; Hao, Yuanqiang [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Ding, Yujie [College of Biochemical Engineering, Anhui Polytechnic University, Wuhu 241000 (China); Wei, Wei; Wang, Qi [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); Qu, Peng, E-mail: qupeng0212@163.com [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xu, Maotian, E-mail: xumaotian@sqnc.edu.cn [Henan Key Laboratory Cultivation Base of Nanobiological Analytical Chemistry, College of Chemistry and Chemical Engineering, Shangqiu Normal University, Shangqiu 476000 (China); College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

    2016-03-17

    Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg{sup 2+} detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb{sup 3+} from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg{sup 2+} into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg{sup 2+}. As a kind of Hg{sup 2+} nanosensor, the probe exhibited excellent selectivity for Hg{sup 2+} and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg{sup 2+} in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg{sup 2+} was achieved based on time-resolved spectroscopy.

  7. Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination

    International Nuclear Information System (INIS)

    Liu, Baoxia; Huang, Yankai; Zhu, Xu; Hao, Yuanqiang; Ding, Yujie; Wei, Wei; Wang, Qi; Qu, Peng; Xu, Maotian

    2016-01-01

    Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg"2"+ detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb"3"+ from the quenching effect of O–H vibration in water molecules. The subsequent addition of Hg"2"+ into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg"2"+. As a kind of Hg"2"+ nanosensor, the probe exhibited excellent selectivity for Hg"2"+ and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg"2"+ in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging. - Highlights: • Lanthanide coordination polymer of Tb-CIP/AMP was synthesized via a simple self-assembly process. • AMP was employed as a bifunctional molecule for both fluorescence sensitization and target recognition. • Hypersensitive detection of Hg"2"+ was achieved based on time-resolved spectroscopy.

  8. The application of positron annihilation lifetime spectroscopy to the study of glassy and partially crystalline materials

    International Nuclear Information System (INIS)

    Zipper, M.D.; Hill, A.J.

    1994-01-01

    The use of positron annihilation lifetime spectroscopy (PALS) as a materials characterisation technique is discussed and is illustrated by examples from the authors' laboratory. A brief guide to interpretation of PALS results for metals, semiconductors, ionic solids and molecular solids is presented; however, the paper focuses on recent results for glassy and partially crystalline ionic and molecular solids. Case studies are presented in which the phenomena studied by PALS include miscibility of polymer blends, plasticization of solid polymer electrolytes, crystallinity in molecular and ionic solids, nanostructure of glass-ceramics, and refractivity of fluoride glasses. Future directions for PALS research of the electronic and defect structures of materials are discussed. 140 refs., 1 tab., 19 figs

  9. Synthesis and characterization of semi-crystalline polyarylene ether nitrile with AIEE feature

    Science.gov (United States)

    Wang, Pan; Li, Kui; Jia, Kun; Liu, Xiaobo

    2017-12-01

    An AIEgen 1, 2-di (4-hydroxyphenyl)-1, 2-diphenylethene (TPE-2OH) was introduced into the back bone of semi-crystalline poly arylene ether nitriles (PEN). The fluorescence spectra results indicated that the derived polymer displayed a typical aggregation-induced emission enhancement (AIEE) active with an emitting peak at ∼470 nm. Then the AIEE active PEN was prepared into films through casting method and realised strong fluorescence emission and excellent mechanics properties. Besides, the crystal AIEE active polymer shows sphere micro-morphology along with a strong blue emission. These findings will open a door for further research on the high performance semi-crystalline PEN at flexible display technology and optical sensors.

  10. Crystallinity evaluation of polyhydroxybutyrate and polycaprolactone blends; Avaliacao da cristalinidade de blendas de polihidroxibutirato e policaprolactona

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, Maxwell P.; Rodrigues, Elton Jorge R.; Tavares, Maria Ines B., E-mail: maxdpc@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas

    2015-07-01

    Polyhydroxybutyrate, PHB, is a polymer obtained through bacterial or synthetic pathways. It has been used in the biomedical field as a matrix for drug delivery, medical implants and as scaffold material for tissue engineering. PHB has high structural organization, which makes it highly crystalline and brittle, making biodegradation difficult, reducing its employability. In order to enhance the mechanical and biological properties of PHB, blends with other polymers, biocompatible or not, are researched and produced. In this regard, blends of PHB and polycaprolactone, PCL, another biopolymer widely used in the biomedical industry, were obtained via solution casting and were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and low field nuclear magnetic resonance (LF-NMR). Results have shown a dependence between PHB's crystallinity index and PCL quantity employed to obtain the blends.(author)

  11. Photo-responsive liquid crystalline epoxy networks with exchangeable disulfide bonds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuzhan [Washington State Univ., Pullman, WA (United States); Zhang, Yuehong [Washington State Univ., Pullman, WA (United States); Rios, Orlando [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Keum, Jong K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kessler, Michael R. [Washington State Univ., Pullman, WA (United States); North Dakota State Univ., Fargo, ND (United States)

    2017-07-27

    The increasing demand for intelligent materials has driven the development of polymers with a variety of functionalities. However, combining multiple functionalities within one polymer is still challenging because of the difficulties encountered in coordinating different functional building blocks during fabrication. In this work, we demonstrate the fabrication of a multifunctional liquid crystalline epoxy network (LCEN) using the combination of thermotropic liquid crystals, photo-responsive azobenzene molecules, and exchangeable disulfide bonds. In addition to shape memory behavior enabled by the reversible liquid crystalline phase transition and photo-induced bending behavior resulting from the photo-responsive azobenzene molecules, the introduction of dynamic disulfide bonds into the LCEN resulted in a structurally dynamic network, allowing the reshaping, repairing, and recycling of the material.

  12. Hybrid ZnO:polymer bulk heterojunction solar cells from a ZnO precursor

    NARCIS (Netherlands)

    Beek, W.J.E.; Slooff, L.H.; Wienk, M.M.; Kroon, J.M.; Janssen, R.A.J.; Kafafi, Z.H.

    2005-01-01

    We describe a simple and new method to create hybrid bulk heterojunction solar cells consisting of ZnO and conjugated polymers. A gel-forming ZnO precursor, blended with conjugated polymers, is converted into crystalline ZnO at temperatures as low as 110 °C. In-situ formation of ZnO in MDMO-PPV

  13. Comparison of the electronic structure of two polymers with strong dipole ordering

    International Nuclear Information System (INIS)

    Xiao Jie; Rosa, Luis G; Poulsen, Matt; Feng, D-Q; Reddy, D Sahadeva; Takacs, James M; Cai, Lei; Zhang, Jiandi; Ducharme, Stephen; Dowben, P A

    2006-01-01

    Two different polymers, with large local electric dipoles, are compared: copolymers of polyvinylidene fluoride with trifluoroethylene [P(VDF-TrFE, 70%:30%)] and polymethylvinylidenecyanide (PMVC). While the different local point group symmetries play a key role, both crystalline polymers exhibit intra-molecular band structure, though the Brillouin zone critical points differ. (letter to the editor)

  14. Full color camouflage in a printable photonic blue-colored polymer

    NARCIS (Netherlands)

    Moirangthem, M.; Schenning, A.P.H.J.

    2018-01-01

    A blue reflective photonic polymer coating which can be patterned in full color, from blue to red, by printing with an aqueous calcium nitrate solution has been fabricated. Color change in the cholesteric liquid-crystalline polymer network over the entire visible spectrum is obtained by the use of

  15. Schottky spectra and crystalline beams

    International Nuclear Information System (INIS)

    Pestrikov, D.V.

    1996-01-01

    In this paper we revise the current dependence of the Schottky noise power of a cooled proton beam previously measured at NAP-M. More careful study of experimental data indicates a linear decrease in the inverse Schottky noise power with an increase in the beam intensity (N). The root of this function determines a threshold current which occurs at N = N th ≅1.2 x 10 8 particles. The inspection of measured Schottky spectra shows that this threshold does not correspond to some collective instability of the measured harmonic of the linear beam density. The found value of N th does not depend on the longitudinal beam temperature. For the case of NAP-M lattice, the study of the spectral properties of the Schottky noise in the crystalline string predicts the current dependence of the equilibrium momentum spread of the beam, which qualitatively agrees with that, recalculated from the NAP-M data. (orig.)

  16. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  17. Antimicrobial polymers.

    Science.gov (United States)

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Picosecond laser ablation of poly-L-lactide: Effect of crystallinity on the material response

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Rocio; Quintana, Iban; Etxarri, Jon [Manufacturing Processes Department, Fundacion TEKNIKER, Av. Otaola 20, 20600, Eibar, Guipuzcoa (Spain); Lejardi, Ainhoa; Sarasua, Jose-Ramon [Department of Mining and Metallurgy Engineering and Materials Science, School of Engineering, University of the Basque Country (EHU-UPV), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2011-11-01

    The picosecond laser ablation of poly-L-lactide (PLLA) as a function of laser fluence and degree of crystallinity was examined. The ablation parameters and the surface modifications were analyzed under various irradiation conditions using laser wavelengths ranging from the ultraviolet through the visible. When processing the amorphous PLLA, both energy threshold and topography varied considerably depending on laser wavelength. Laser irradiation showed a reduction in the energy ablation threshold as the degree of crystallinity increased, probably related to photomechanical effects involved in laser ablation with ultra-short pulses and the lower stress accommodation behavior of semicrystalline polymers. In particular, cooperative chain motions are impeded by the higher degree of crystallinity, showing fragile mechanical behavior and lower energy dissipation. The experimental results on ablation rate versus laser energy showed that UV laser ablation on semicrystalline PLLA was more efficient than the visible ablation, i.e., it exhibits higher etch rates over a wide range of pulse energy conditions. These results were interpreted in terms of photo-thermal and photo-chemical response of polymers as a function of material micro-structure and incident laser wavelength. High quality micro-grooves were produced in amorphous PLLA, reveling the potential of ultra-fast laser processing technique in the field of micro-structuring biocompatible and biodegradable polymers for biomedical applications.

  19. Picosecond laser ablation of poly-L-lactide: Effect of crystallinity on the material response

    International Nuclear Information System (INIS)

    Ortiz, Rocio; Quintana, Iban; Etxarri, Jon; Lejardi, Ainhoa; Sarasua, Jose-Ramon

    2011-01-01

    The picosecond laser ablation of poly-L-lactide (PLLA) as a function of laser fluence and degree of crystallinity was examined. The ablation parameters and the surface modifications were analyzed under various irradiation conditions using laser wavelengths ranging from the ultraviolet through the visible. When processing the amorphous PLLA, both energy threshold and topography varied considerably depending on laser wavelength. Laser irradiation showed a reduction in the energy ablation threshold as the degree of crystallinity increased, probably related to photomechanical effects involved in laser ablation with ultra-short pulses and the lower stress accommodation behavior of semicrystalline polymers. In particular, cooperative chain motions are impeded by the higher degree of crystallinity, showing fragile mechanical behavior and lower energy dissipation. The experimental results on ablation rate versus laser energy showed that UV laser ablation on semicrystalline PLLA was more efficient than the visible ablation, i.e., it exhibits higher etch rates over a wide range of pulse energy conditions. These results were interpreted in terms of photo-thermal and photo-chemical response of polymers as a function of material micro-structure and incident laser wavelength. High quality micro-grooves were produced in amorphous PLLA, reveling the potential of ultra-fast laser processing technique in the field of micro-structuring biocompatible and biodegradable polymers for biomedical applications.

  20. Radiation induced crystallinity damage in poly(L-lactic acid)

    CERN Document Server

    Kantoglu, O

    2002-01-01

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

  1. Microinjection molding of thermoplastic polymers: morphological comparison with conventional injection molding

    International Nuclear Information System (INIS)

    Giboz, Julien; Mélé, Patrice; Copponnex, Thierry

    2009-01-01

    The skin–core crystalline morphology of injection-molded semi-crystalline polymers is well documented in the scientific literature. The thermomechanical environment provokes temperature and shear gradients throughout the entire thickness of the part during molding, thus influencing the polymer crystallization. Crystalline morphologies of a high-density polyethylene (HDPE) micromolded part (μpart) and a classical part (macropart) are compared with optical, thermal and x-ray diffraction analyses. Results show that the crystalline morphologies with regard to thickness vary between the two parts. While a 'skin–core' morphology is present for the macropart, the μpart exhibits a specific 'core-free' morphology, i.e. no spherulite is present at the center of the thickness. This result seems to be generated under the specific conditions used in microinjection molding that lead to the formation of smaller and more oriented crystalline entities

  2. Implicit implementation and consistent tangent modulus of a viscoplastic model for polymers

    OpenAIRE

    ACHOUR-RENAULT, Nadia; CHATZIGEORGIOU, George; MERAGHNI, Fodil; CHEMISKY, Yves; FITOUSSI, Joseph

    2015-01-01

    In this work, the phenomenological viscoplastic DSGZ model[Duan, Y., Saigal, A., Greif, R., Zimmerman, M. A., 2001. A Uniform Phenomenological Constitutive Model for Glassy and Semicrystalline Polymers. Polymer Engineering and Science 41 (8), 1322-1328], developed for glassy or semi-crystalline polymers, is numerically implemented in a three dimensional framework, following an implicit formulation. The computational methodology is based on the radial return mapping algorithm. This implicit fo...

  3. Drying of semicrystalline polymers: Mathematical modeling and experimental characterization of poly(vinyl alcohol) films

    OpenAIRE

    Wong, Sim-Siong; Altınkaya, Sacide; Mallapragada, Surya K.

    2004-01-01

    A mathematical model was developed to predict the drying mechanism of semicrystalline polymers involving multiple solvents. Since drying of semicrystalline polymers can be accompanied by changes in polymer degree of crystallinity, the model integrates crystallization kinetics and the Vrentas-Duda diffusion model to provide a better understanding of the mechanism. The model considers the effect of external conditions such as temperature, film shrinkage and diffusion and evaporation of multiple...

  4. Irradiation effects on perfluorinated polymers

    International Nuclear Information System (INIS)

    Lappan, U.; Geissler, U.; Haeussler, L.; Pompe, G.; Scheler, U.; Lunkwitz, K.

    2002-01-01

    Complete text of publication follows. High-energy radiation affects the properties of polymers by chain scission and crosslinking reactions. Both types of reaction occur simultaneously in irradiated polymers. However, one process will usually predominate, depending on the chemical structure of the polymer and the irradiation conditions such as temperature and atmosphere. Polytetrafluoroethylene (PTFE) undergoes predominantly chain scission, if the irradiation is performed at room temperature. This shortcoming is exploited by converting PTFE into low molecular weight micropowders. The use of PTFE micropowders functionalized with COOH groups as additive in polyamides to improve the sliding properties of the materials has been studied. During the compounding process in a twin screw extruder the COOH groups of the irradiated PTFE react with the polyamides. For these studies, it became necessary to investigate the content of end groups in irradiated PTFE by FTIR and 19 F solid-state NMR. These date were used to calculate number-average molecular weights. The ratios of COOH groups to CF 3 groups are discussed in terms of the mechanism of PTFE degradation. If PTFE is irradiated at temperatures above its crystalline melting point in an oxygen-free atmosphere, branching and crosslinking occur. The dependence of radiation effects on perfluorinated copolymers (FEP, PFA) on temperature has been studied. Melt flow index measurements have shown that branching and crosslinking predominate over chain scission with increasing irradiation temperature both in FEP and in PFA. Quantitative analysis of 19 F solid-state NMR data has shown that the content of branching groups (>CF-) exceeds the content of end groups in the case of PFA irradiated above its crystalline melting point. The formation of COF and COOH groups in the irradiated PFA is interpreted as a result of partial degradation of perfluorovinyl ether comonomer units

  5. Hybrid zinc oxide conjugated polymer bulk heterojunction solar cells

    NARCIS (Netherlands)

    Beek, W.J.E.; Wienk, M.M.; Kemerink, M.; Yang, X.N.; Janssen, R.A.J.

    2005-01-01

    Bulk heterojunction photovoltaic devices based on blends of a conjugated polymer poly[2-methoxy-5-(3‘,7‘-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) as electron donor and crystalline ZnO nanoparticles (nc-ZnO) as electron acceptor have been studied. Composite nc-ZnO:MDMO-PPV films were cast

  6. Silk fibroin as an organic polymer for controlled drug delivery

    NARCIS (Netherlands)

    Hofmann, S.; Foo, S.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.L.; Merkle, H.P.; Meinel, L.

    2006-01-01

    The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins,

  7. Diketopyrrolopyrrole Polymers for Organic Solar Cells.

    Science.gov (United States)

    Li, Weiwei; Hendriks, Koen H; Wienk, Martijn M; Janssen, René A J

    2016-01-19

    Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a result, the power conversion efficiencies (PCEs) of solar cells based on conjugated polymers as electron donor and fullerene derivatives as electron acceptor have exceeded 10% in single-junction and 11% in multijunction devices. Despite these efforts, it is notoriously difficult to establish thorough structure-property relationships that will be required to further optimize existing high-performance polymers to their intrinsic limits. In this Account, we highlight progress on the development and our understanding of diketopyrrolopyrrole (DPP) based conjugated polymers for polymer solar cells. The DPP moiety is strongly electron withdrawing and its polar nature enhances the tendency of DPP-based polymers to crystallize. As a result, DPP-based conjugated polymers often exhibit an advantageously broad and tunable optical absorption, up to 1000 nm, and high mobilities for holes and electrons, which can result in high photocurrents and good fill factors in solar cells. Here we focus on the structural modifications applied to DPP polymers and rationalize and explain the relationships between chemical structure and organic photovoltaic performance. The DPP polymers can be tuned via their aromatic substituents, their alkyl side chains, and the nature of the π-conjugated segment linking the units along the polymer chain. We show that these building blocks work together in determining the molecular conformation, the optical properties, the charge carrier mobility, and the solubility of the polymer. We identify the latter as a decisive parameter for DPP-based organic solar cells because it regulates the diameter of the semicrystalline DPP polymer fibers that form in the photovoltaic blends with

  8. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  9. Terahertz spectroscopic analysis of crystal orientation in polymers

    Science.gov (United States)

    Azeyanagi, Chisato; Kaneko, Takuya; Ohki, Yoshimichi

    2018-05-01

    Terahertz time-domain spectroscopy (THz-TDS) is attracting keen attention as a new spectroscopic tool for characterizing various materials. In this research, the possibility of analyzing the crystal orientation in a crystalline polymer by THz-TDS is investigated by measuring angle-resolved THz absorption spectra for sheets of poly(ethylene terephthalate), poly(ethylene naphthalate), and poly(phenylene sulfide). The resultant angle dependence of the absorption intensity of each polymer is similar to that of the crystal orientation examined using pole figures of X-ray diffraction. More specifically, THz-TDS can indicate the alignment of molecules in polymers.

  10. Initial Drug Dissolution from Amorphous Solid Dispersions Controlled by Polymer Dissolution and Drug-Polymer Interaction.

    Science.gov (United States)

    Chen, Yuejie; Wang, Shujing; Wang, Shan; Liu, Chengyu; Su, Ching; Hageman, Michael; Hussain, Munir; Haskell, Roy; Stefanski, Kevin; Qian, Feng

    2016-10-01

    To identify the key formulation factors controlling the initial drug and polymer dissolution rates from an amorphous solid dispersion (ASD). Ketoconazole (KTZ) ASDs using PVP, PVP-VA, HMPC, or HPMC-AS as polymeric matrix were prepared. For each drug-polymer system, two types of formulations with the same composition were prepared: 1. Spray dried dispersion (SDD) that is homogenous at molecular level, 2. Physical blend of SDD (80% drug loading) and pure polymer (SDD-PB) that is homogenous only at powder level. Flory-Huggins interaction parameters (χ) between KTZ and the four polymers were obtained by Flory-Huggins model fitting. Solution (13)C NMR and FT-IR were conducted to investigate the specific drug-polymer interaction in the solution and solid state, respectively. Intrinsic dissolution of both the drug and the polymer from ASDs were studied using a Higuchi style intrinsic dissolution apparatus. PXRD and confocal Raman microscopy were used to confirm the absence of drug crystallinity on the tablet surface before and after dissolution study. In solid state, KTZ is completely miscible with PVP, PVP-VA, or HPMC-AS, demonstrated by the negative χ values of -0.36, -0.46, -1.68, respectively; while is poorly miscible with HPMC shown by a positive χ value of 0.23. According to solution (13)C NMR and FT-IR studies, KTZ interacts with HPMC-AS strongly through H-bonding and dipole induced interaction; with PVPs and PVP-VA moderately through dipole-induced interactions; and with HPMC weakly without detectable attractive interaction. Furthermore, the "apparent" strength of drug-polymer interaction, measured by the extent of peak shift on NMR or FT-IR spectra, increases with the increasing number of interacting drug-polymer pairs. For ASDs with the presence of considerable drug-polymer interactions, such as KTZ/PVPs, KTZ/PVP-VA, or KTZ /HPMC-AS systems, drug released at the same rate as the polymer when intimate drug-polymer mixing was ensured (i.e., the SDD systems

  11. Crystalline silicotitanate gate review analysis

    International Nuclear Information System (INIS)

    Schlahta, S.N.; Carreon, R.; Gentilucci, J.A.

    1997-11-01

    Crystalline silicotitanate (CST) is an ion-exchange method for removing radioactive cesium from tank waste to allow the separation of the waste into high- and low-level fractions. The CST, originally developed Sandia National Laboratories personnel in association with Union Oil Products Corporation, has both a high affinity and selectivity for sorbing cesium-137 from highly alkaline or acidic solutions. For several years now, the U.S. Department of Energy has funded work to investigate applying CST to large-scale removal of cesium-137 from radioactive tank wastes. In January 1997, an expert panel sponsored by the Tanks Focus Area met to review the current state of the technology and to determine whether it was ready for routine use. The review also sought to identify any technical issues that must be resolved or additional CST development that must occur before full implementation by end-users. The CST Gate Review Group concluded that sufficient work has been done to close developmental work on CST and turn the remaining site-specific tasks over to the users. This report documents the review group''s findings, issues, concerns, and recommendations as well as responses from the Tanks Focus Area expert staff to specific pretreatment and immobilization issues

  12. Thermal, crystallinity and morphological studies of the filled RBD palm kernel oil polyurethane foam

    International Nuclear Information System (INIS)

    Khairiah Badri; Sahrim Ahmad; Sarani Zakaria

    2000-01-01

    The synthesis of RBD palm kernel oil (PKO) polyurethane polyol and the polyurethane foam has well been documented. However, less study has been put in discovering the thermal properties and crystallinity of the foam. It is also an initiative to investigate the effect of oil palm empty fruit bunch (EFB) and sorbitol as fillers in the polyurethane (PU) foam to these properties. Thermogravimetric (TGA) investigation of the PKO PU foam was performed to study their decompositions. The semi-crystalline nature of EFB-filled PU was confirmed by x-ray diffratogram and DSC thermogram of glass transition temperature, T g . The x-ray diffraction (XRD) study of the unfilled PU showed a broad amorphous halo, indicative of absence of crystallinity in the polymer, which has been explained as due to strong hydrogen bonding in the hard phase. Overall crystallinity decreases with an increase in the polyester content in agreement with the XRD results. The crystallinity however, increases with the inclusion of EFB in the polyurethane system. This study was followed by the observation of the surface morphologies of the PKO PU foam with and without fillers. The scanning electron micrographs verified the finding on the improved k-factor values. (Author)

  13. SULFUR POLYMER ENCAPSULATION

    International Nuclear Information System (INIS)

    KALB, P.

    2001-01-01

    Sulfur polymer cement (SPC) is a thermoplastic polymer consisting of 95 wt% elemental sulfur and 5 wt% organic modifiers to enhance long-term durability. SPC was originally developed by the U.S. Bureau of Mines as an alternative to hydraulic cement for construction applications. Previous attempts to use elemental sulfur as a construction material in the chemical industry failed due to premature degradation. These failures were caused by the internal stresses that result from changes in crystalline structure upon cooling of the material. By reacting elemental sulfur with organic polymers, the Bureau of Mines developed a product that successfully suppresses the solid phase transition and significantly improves the stability of the product. SPC, originally named modified sulfur cement, is produced from readily available, inexpensive waste sulfur derived from desulfurization of both flue gases and petroleum. The commercial production of SPC is licensed in the United States by Martin Resources (Odessa, Texas) and is marketed under the trade name Chement 2000. It is sold in granular form and is relatively inexpensive ((approx)$0.10 to 0.12/lb). Application of SPC for the treatment of radioactive, hazardous, and mixed wastes was initially developed and patented by Brookhaven National Laboratory (BNL) in the mid-1980s (Kalb and Colombo, 1985; Colombo et al., 1997). The process was subsequently investigated by the Commission of the European Communities (Van Dalen and Rijpkema, 1989), Idaho National Engineering Laboratory (Darnell, 1991), and Oak Ridge National Laboratory (Mattus and Mattus, 1994). SPC has been used primarily in microencapsulation applications but can also be used for macroencapsulation of waste. SPC microencapsulation has been demonstrated to be an effective treatment for a wide variety of wastes, including incinerator hearth and fly ash; aqueous concentrates such as sulfates, borates, and chlorides; blowdown solutions; soils; and sludges. It is not

  14. The effect of crystallinity on cell growth in semi-crystalline microcellular foams by solid-state process: modeling and numerical simulation

    Science.gov (United States)

    Rezvanpanah, Elham; Ghaffarian Anbaran, S. Reza

    2017-11-01

    This study establishes a model and simulation scheme to describe the effect of crystallinity as one of the most effective parameters on cell growth phenomena in a solid batch foaming process. The governing model of cell growth dynamics, based on the well-known ‘Cell model’, is attained in details. To include the effect of crystallinity in the model, the properties of the polymer/gas mixtures (i.e. solubility, diffusivity, surface tension and viscosity) are estimated by modifying relations to consider the effect of crystallinity. A finite element-finite difference (FEFD) method is employed to solve the highly nonlinear and coupled equations of cell growth dynamics. The proposed simulation is able to evaluate all properties of the system at the given process condition and uses them to calculate the cell size, pressure and gas concentration gradient with time. A high-density polyethylene/nitrogen (HDPE/N2) system is used herein as a case study. Comparing the simulation results with the others works and experimental results verify the accuracy of the simulation scheme. The cell growth is a complicated combination of several phenomena. This study attempted to reach a better understanding of cell growth trend, driving and retarding forces and the effect of crystallinity on them.

  15. Hydraulic testing in crystalline rock

    International Nuclear Information System (INIS)

    Almen, K.E.; Andersson, J.E.; Carlsson, L.; Hansson, K.; Larsson, N.A.

    1986-12-01

    Swedish Geolocical Company (SGAB) conducted and carried out single-hole hydraulic testing in borehole Fi 6 in the Finnsjoen area of central Sweden. The purpose was to make a comprehensive evaluation of different methods applicable in crystalline rocks and to recommend methods for use in current and scheduled investigations in a range of low hydraulic conductivity rocks. A total of eight different methods of testing were compared using the same equipment. This equipment was thoroughly tested as regards the elasticity of the packers and change in volume of the test section. The use of a hydraulically operated down-hole valve enabled all the tests to be conducted. Twelve different 3-m long sections were tested. The hydraulic conductivity calculated ranged from about 5x10 -14 m/s to 1x10 -6 m/s. The methods used were water injection under constant head and then at a constant rate-of-flow, each of which was followed by a pressure fall-off period. Water loss, pressure pulse, slug and drill stem tests were also performed. Interpretation was carried out using standard transient evaluation methods for flow in porous media. The methods used showed themselves to be best suited to specific conductivity ranges. Among the less time-consuming methods, water loss, slug and drill stem tests usually gave somewhat higher hydraulic conductivity values but still comparable to those obtained using the more time-consuming tests. These latter tests, however, provided supplementary information on hydraulic and physical properties and flow conditions, together with hydraulic conductivity values representing a larger volume of rock. (orig./HP)

  16. Efecto de la época de plantación en la dinámica de la emergencia de caña semilla de alta calidad (termotratada y micropropagada de las variedades CP 65-357 y LCP 85-384 Effect of planting date on emergence dynamics of high quality CP 65-357 and LCP 85-384 seed cane (hot-water treated and micropropagated

    Directory of Open Access Journals (Sweden)

    Patricia A. Digonzelli

    2005-12-01

    Full Text Available Se evalúa el efecto de la época de plantación en la dinámica de la emergencia de caña semilla de alta calidad (micropropagada y termotratada de las variedades CP 65-357 y LCP 85-384, en condiciones de disponibilidad hídrica adecuada. La caña semilla micropropagada y termotratada (50ºC, 2 hs se plantó, con una densidad de 15 yemas/m, en tres épocas contrastantes: otoño, invierno y primavera. El material empleado estaba libre de escaldadura de la hoja (Xanthomonas albilineans y achaparramiento (Leifsonia xyli subsp. xyli. La época de plantación afectó todas las variables de la dinámica de la emergencia en las dos variedades y en ambos orígenes de la semilla. El origen afectó significativamente el inicio y la duración de la emergencia (t e y t50, pero no tuvo efecto en el porcentaje final ni en la tasa media de emergencia. La emergencia (% fue mayor en la plantación de octubre, que en las de mayo y agosto (59%, 35% y 45%, respectivamente. El te y el t50 fueron mayores en mayo que en agosto y octubre. La semilla micropropagada presentó, en general, valores de t e y t50 menores que la termotratada. La época de plantación fue el principal factor que afectó la dinámica de la emergencia de caña semilla de alta calidad de CP 65-357 y LCP 85-384. La variedad y el origen de la semilla afectaron significativamente, aunque en menor magnitud que la época de plantación, el inicio y la duración de la fase de emergencia.Planting date influence on emergence dynamics of high quality CP 65-357 and LCP 85-384 seed cane (hot-water treated and micropropagated, without humidity constraints, was evaluated. Material used was free from leaf scald disease (Xanthomonas albilineans and ratoon stunting disease (Leifsonia xyli subsp. xyli. Seed cane, micropropagated and hot-water treated (50ºC, 2 hours, was planted with a 15 buds/m density in three contrasting dates: autumn, winter and spring. The material was irrigated during the trial. Planting

  17. Gas-phase synthesis of magnetic metal/polymer nanocomposites

    Science.gov (United States)

    Starsich, Fabian H. L.; Hirt, Ann M.; Stark, Wendelin J.; Grass, Robert N.

    2014-12-01

    Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

  18. Synthesis of polymer nanostructures with conductance switching properties

    Science.gov (United States)

    Su, Kai; Nuraje, Nurxat; Zhang, Lingzhi; Matsui, Hiroshi; Yang, Nan Loh

    2015-03-03

    The present invention is directed to crystalline organic polymer nanoparticles comprising a conductive organic polymer; wherein the crystalline organic polymer nanoparticles have a size of from 10 nm to 200 nm and exhibits two current-voltage states: (1) a high resistance current-voltage state, and (2) a low resistance current-voltage state, wherein when a first positive threshold voltage (V.sub.th1) or higher positive voltage, or a second negative threshold voltage (V.sub.th2) or higher negative voltage is applied to the nanoparticle, the nanoparticle exhibits the low-resistance current-voltage state, and when a voltage less positive than the first positive threshold voltage or a voltage less negative than the second negative threshold voltage is applied to the nanoparticle, the nanoparticle exhibits the high-resistance current-voltage state. The present invention is also directed methods of manufacturing the nanoparticles using novel interfacial oxidative polymerization techniques.

  19. Crystallization of Polymers Investigated by Temperature-Modulated DSC

    Directory of Open Access Journals (Sweden)

    Maria Cristina Righetti

    2017-04-01

    Full Text Available The aim of this review is to summarize studies conducted by temperature-modulated differential scanning calorimetry (TMDSC on polymer crystallization. This technique can provide several advantages for the analysis of polymers with respect to conventional differential scanning calorimetry. Crystallizations conducted by TMDSC in different experimental conditions are analysed and discussed, in order to illustrate the type of information that can be deduced. Isothermal and non-isothermal crystallizations upon heating and cooling are examined separately, together with the relevant mathematical treatments that allow the evolution of the crystalline, mobile amorphous and rigid amorphous fractions to be determined. The phenomena of ‘reversing’ and ‘reversible‘ melting are explicated through the analysis of the thermal response of various semi-crystalline polymers to temperature modulation.

  20. Natural polymers: an overview

    CSIR Research Space (South Africa)

    John, MJ

    2012-08-01

    Full Text Available The scarcity of natural polymers during the world war years led to the development of synthetic polymers like nylon, acrylic, neoprene, styrene-butadiene rubber (SBR) and polyethylene. The increasing popularity of synthetic polymers is partly due...

  1. On γ-relaxation process in crystallizable polymers

    International Nuclear Information System (INIS)

    Mindiyarov, Kh.G.; Zelenev, Yu.V.; Bartenev, G.M.

    1975-01-01

    In the present paper, with the aid of radiothermoluminescence technique γ-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to γ-rays of Co 60 at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the α - γ-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP α-maximum may be absent. Dependence has been studied of the luminescence intensity in the α- and γ-maxima (Isub(α)/Isub(γ)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(γ)re of crystallinity degree

  2. Efectos de la calidad de la caña semilla en los componentes del rendimiento cultural de las variedades CP65-357 y LCP85-384 (Saccharum spp. según diferentes edades de corte (Parte I Effects of seedcane quality on yielding components of varieties CP65-357 and LCP85-384 (Saccharum spp. in different crops (Part I

    Directory of Open Access Journals (Sweden)

    María I. Cuenya

    2007-06-01

    Full Text Available Las principales variedades de caña de azúcar cultivadas en Tucumán mostraron, hasta hace pocos años, una elevada infección con achaparramiento de la caña soca, enfermedad sistémica causada por Leifsonia xyli subsp. xyli, ampliamente reconocida por su efecto detrimental sobre el rendimiento cultural. Esta situación fue consecuencia de que los productores cañeros utilizaban caña semilla proveniente de lotes comerciales en lugar de caña semilla de semilleros saneados. El objetivo del presente trabajo fue evaluar el efecto de la calidad de la semilla en los componentes del rendimiento cultural en LCP85-384 y CP65-357, dos variedades ampliamente difundidas en Tucumán. Para cada variedad se evaluaron dos alternativas con respecto a la calidad de la semilla: Semilla de Alta Calidad (SAC proveniente de micropropagación in vitro y Semilla Comercial (SC proveniente de un cañaveral comercial. Se implantó un ensayo de acuerdo a un diseño en bloques completos al azar con seis repeticiones. En caña planta, soca 1 y soca 2 se evaluaron: número de tallos/parcela, peso, altura y diámetro del tallo y rendimiento de caña/ha. Se efectuaron análisis de la varianza y pruebas de comparación de medias (DLS de Fisher. En ambas variedades los componentes del rendimiento cultural más afectados por la calidad de la semilla utilizada fueron el peso y la altura de tallos a través de edades de corte. Para CP65-357 y LCP85-384 los tratamientos con SAC produjeron, en promedio, tallos más altos y más pesados en comparación con los tratamientos obtenidos a partir de SC. El diámetro de tallos no se afectó por la calidad de la semilla. Se detectaron importantes disminuciones en el rendimiento cultural (t caña/ha por la utilización de SC (10-25% en CP65-357 y 19-25% en LCP85-384 a través de las edades de corte. Estos resultados sustentan la utilización generalizada de semilleros saneados, sistema puesto en marcha por la EEAOC a partir del año 2000

  3. The quest for crystalline ion beams

    CERN Document Server

    Schramm, U; Bussmann, M; Habs, D

    2002-01-01

    The phase transition of an ion beam into its crystalline state has long been expected to dramatically influence beam dynamics beyond the limitations of standard accelerator physics. Yet, although considerable improvement in beam cooling techniques has been made, strong heating mechanisms inherent to existing high-energy storage rings have prohibited the formation of the crystalline state in these machines up to now. Only recently, laser cooling of low-energy beams in the table-top rf quadrupole storage ring PAaul Laser cooLing Acceleration System (PALLAS) has lead to the experimental realization of crystalline beams. In this article, the quest for crystalline beams as well as their unique properties as experienced in PALLAS will be reviewed.

  4. Mechanical dispersion in fractured crystalline rock systems

    International Nuclear Information System (INIS)

    Lafleur, D.W.; Raven, K.G.

    1986-12-01

    This report compiles and evaluates the hydrogeologic parameters describing the flow of groundwater and transport of solutes in fractured crystalline rocks. This report describes the processes of mechanical dispersion in fractured crystalline rocks, and compiles and evaluates the dispersion parameters determined from both laboratory and field tracer experiments. The compiled data show that extrapolation of the reliable test results performed over intermediate scales (10's of m and 10's to 100's of hours) to larger spatial and temporal scales required for performance assessment of a nuclear waste repository in crystalline rock is not justified. The reliable measures of longitudinal dispersivity of fractured crystalline rock are found to range between 0.4 and 7.8 m

  5. Excimer fluorescence of liquid crystalline systems

    Science.gov (United States)

    Sakhno, Tamara V.; Khakhel, Oleg A.; Barashkov, Nikolay N.; Korotkova, Irina V.

    1996-04-01

    The method of synchronous scanning fluorescence spectroscopy shows a presence of dimers of pyrene in a polymeric matrix. The results suggest that excimer formation takes place with dimers in liquid crystalline systems.

  6. Syntheses, molecular and crystalline architectures, and ...

    Indian Academy of Sciences (India)

    Syntheses, molecular and crystalline architectures, and luminescence behaviour of terephthalate bridged heptacoordinated dinuclear lead(II) complexes containing a pentadentate N-donor Schiff base. SUBHASIS ROYa, SOMNATH CHOUBEYa, SUMITAVA KHANa, KISHALAY BHARa,. PARTHA MITRAb and BARINDRA ...

  7. Electrochemical synthesis of highly crystalline copper nanowires

    International Nuclear Information System (INIS)

    Kaur, Amandeep; Gupta, Tanish; Kumar, Akshay; Kumar, Sanjeev; Singh, Karamjeet; Thakur, Anup

    2015-01-01

    Copper nanowires were fabricated within the pores of anodic alumina template (AAT) by template synthesis method at pH = 2.9. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to investigate the structure, morphology and composition of fabricated nanowires. These characterizations revealed that the deposited copper nanowires were highly crystalline in nature, dense and uniform. The crystalline copper nanowires are promising in application of future nanoelectronic devices and circuits

  8. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Keywords. Polymer dynamics; reptation; domain dynamics biomolecules. Abstract. Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the ...

  9. Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

    International Nuclear Information System (INIS)

    Bergamasco, Juliana; Araujo, Marcelo V. de; Vasconcellos, Adriano de; Luizon Filho, Roberto A.; Hatanaka, Rafael R.; Giotto, Marcus V.; Aranda, Donato A.G.; Nery, José G.

    2013-01-01

    Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg −1 ), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg −1 ). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23 Na- and 13 C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. Highlights: • Rhizomucor miehei lipase was immobilized on PVA microspheres (PVA4, PVA12, PVA25). • Polymer-enzyme complex was characterized by XDR, SEM, ATR-FTIR, 13 C-CPMAS-NMR, 23 Na-MAS-NMR. • Polymer-enzymes (PVA12 and PVA25) enzymes yielded considerable amount of ethyl esters. • Synergistic effect was observed for the polymer-enzyme complexes

  10. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    KAUST Repository

    Dimitrov, Stoichko

    2016-01-13

    The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  11. Effect of gamma radiation on the structural and optical properties of Polyethyleneterephthalate (PET) polymer

    International Nuclear Information System (INIS)

    Siddhartha; Aarya, Suveda; Dev, Kapil; Raghuvanshi, Suresh Kumar; Krishna, J.B.M.; Wahab, M.A.

    2012-01-01

    Effect of 1.25 MeV gamma radiation on the structural and optical properties of virgin and gamma irradiated (0–2000 kGy) Polyethyleneterephthalate (PET) polymer samples are analyzed using powder X-ray diffractometer and UV–vis spectrophotometer. Diffraction pattern of PET polymer indicates the semi-crystalline in nature whereas the crystallinity increases with increasing dose of irradiation. The remarkable variation in crystallite size is also observed. The absorption and activation energy increase and the optical band gap (E g ) decreases with increasing dose in UV–vis studies. The existence of the maximum absorption, their shifting and broadening due to gamma irradiation in PET polymer are also discussed. - Highlights: ► PET is the transparent polymer and semi- crystalline. ► Crystallinity increases with increasing dose of irradiation of polymer. ► The remarkable variation in crystallite sizes was also observed in polymer. ► The absorption and activation energy increase and where as the optical band gap (E g ) decrease with increasing dose.

  12. Composite Polymer Electrolytes: Nanoparticles Affect Structure and Properties

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2016-11-01

    Full Text Available Composite polymer electrolytes (CPEs can significantly improve the performance in electrochemical devices such as lithium-ion batteries. This review summarizes property/performance relationships in the case where nanoparticles are introduced to polymer electrolytes. It is the aim of this review to provide a knowledge network that elucidates the role of nano-additives in the CPEs. Central to the discussion is the impact on the CPE performance of properties such as crystalline/amorphous structure, dielectric behavior, and interactions within the CPE. The amorphous domains of semi-crystalline polymer facilitate the ion transport, while an enhanced mobility of polymer chains contributes to high ionic conductivity. Dielectric properties reflect the relaxation behavior of polymer chains as an important factor in ion conduction. Further, the dielectric constant (ε determines the capability of the polymer to dissolve salt. The atom/ion/nanoparticle interactions within CPEs suggest ways to enhance the CPE conductivity by generating more free lithium ions. Certain properties can be improved simultaneously by nanoparticle addition in order to optimize the overall performance of the electrolyte. The effects of nano-additives on thermal and mechanical properties of CPEs are also presented in order to evaluate the electrolyte competence for lithium-ion battery applications.

  13. Electron beam effects on gelatin polymer

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Shimazaki, Kleber; Souza, Clecia de M.; Moura, Esperidiana A.B.; Mastro, Nelida L. del, E-mail: patyoko@yahoo.co [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Colombo, Maria A., E-mail: mascolombo@yahoo.com.b [Faculdade de Tecnologia da Zona Leste, Sao Paulo, SP (Brazil)

    2009-07-01

    The main field of electron-beam radiation processing applications is the modification of polymeric material. Polymer development includes new pathways to produce natural polymers with better mechanical and barrier properties and thermal stability. The aim of this paper was to investigate the behavior of a gelatin/acrylamide polymer treated by electron-beam radiation. Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular mass derived by hydrolytic action from animal collagen, a fibrous insoluble protein, which is widely found in nature as the major constituent of skin, bones and connective tissue. Hydrolyzed collagen is composed of a unique sequence of amino acids, characterized particularly by the high content of glycine, proline and hydroxyproline. Among biomaterials, gelatin is an interesting material because is a partially crystalline polymer and has a relatively low melting point. Samples of gelatin together with glycerin as plasticizer and acrylamide as copolymer were irradiated with doses of 10 kGy and 40 kGy, using an electron beam accelerator, dose rate 22.41kGy/s, at room temperature in presence of air. After irradiation, some preliminary analyses were done like viscometry, texture analyses and colorimetry. The results of the diverse tests showed changes that can be ascribed to radiation-induced crosslinking. The electron-beam processed acrylamide-gelatin polymer using glycerin as plasticizer must be first extensively characterized before to be used for general applications. (author)

  14. Electron beam effects on gelatin polymer

    International Nuclear Information System (INIS)

    Inamura, Patricia Y.; Shimazaki, Kleber; Souza, Clecia de M.; Moura, Esperidiana A.B.; Mastro, Nelida L. del; Colombo, Maria A.

    2009-01-01

    The main field of electron-beam radiation processing applications is the modification of polymeric material. Polymer development includes new pathways to produce natural polymers with better mechanical and barrier properties and thermal stability. The aim of this paper was to investigate the behavior of a gelatin/acrylamide polymer treated by electron-beam radiation. Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular mass derived by hydrolytic action from animal collagen, a fibrous insoluble protein, which is widely found in nature as the major constituent of skin, bones and connective tissue. Hydrolyzed collagen is composed of a unique sequence of amino acids, characterized particularly by the high content of glycine, proline and hydroxyproline. Among biomaterials, gelatin is an interesting material because is a partially crystalline polymer and has a relatively low melting point. Samples of gelatin together with glycerin as plasticizer and acrylamide as copolymer were irradiated with doses of 10 kGy and 40 kGy, using an electron beam accelerator, dose rate 22.41kGy/s, at room temperature in presence of air. After irradiation, some preliminary analyses were done like viscometry, texture analyses and colorimetry. The results of the diverse tests showed changes that can be ascribed to radiation-induced crosslinking. The electron-beam processed acrylamide-gelatin polymer using glycerin as plasticizer must be first extensively characterized before to be used for general applications. (author)

  15. Melting point of polymers under high pressure Part I: Influence of the polymer properties

    International Nuclear Information System (INIS)

    Seeger, Andreas; Freitag, Detlef; Freidel, Frank; Luft, Gerhard

    2004-01-01

    The pressure dependence of the melting point of various polymers including homo- and copolymers (HDPE, LDPE, PP and ethylene vinyl acetate copolymers (EVA)) was investigated under nitrogen atmosphere up to 330 MPa within a high pressure differential thermal analysis cell designed by our group. The properties of the polymers (vinylacetate content, melt flow index, molecular weight, isotactic index, crystallinity, density, and frequency of branching) have been correlated with the change of the melting point under pressure (dT m /dp). It could be shown that the melting point always increases linearly with pressure up to 330 MPa. The pressure dependence was found to be in the range of 11-17 K/(100 MPa). From these results it is possible to approximate dT m /dp using the enthalpy of fusion of the polymers at ambient pressure

  16. Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level

    International Nuclear Information System (INIS)

    Stimson, Lorna M.

    2003-01-01

    Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a single dendrimer molecule in the gas phase at the atomistic level, semi-atomistic molecular dynamics of a single molecule in liquid crystalline solvents and a coarse-grained molecular dynamics study of the dendrimer in the bulk. The coarse-grained model has been developed and parameterized using the results of the atomistic and semi-atomistic work. The single molecule studies showed that the liquid crystalline dendrimer was able to change its structure by conformational changes in the flexible chains that link the mesogenic groups to the core. Structural change was seen under the application of a mean field ordering potential in the gas phase, and in the presence of liquid crystalline solvents. No liquid crystalline phases were observed for the bulk phase studies of the coarse-grained model. However, when the length of the mesogenic units was increased there was some evidence for microphase separation in these systems. (author)

  17. A preliminary assessment of the effects of radiation on polymer properties

    International Nuclear Information System (INIS)

    Dickson, L.W.

    1988-01-01

    The literature on the effects of radiation on the properties of various polymers and composites has been briefly reviewed for the purpose of identifying polymeric materials that could be irradiated to improve their performance. Radiation treatment of polymers may lead to cross-linking or chain scission reactions, depending on the chemical nature of the polymer. Cross-linking generally leads to an improvement in the mechanical properties of the polymer. Chain scission leads to deterioration in mechanical properties. The properties of irradiated polymers also depend on the degree of polymer crystallinity and the irradiation conditions, including dose rate and the presence of oxygen, cross-linking agents and other additives. A 30% increase in the tensile strength of many polymers may be obtained by radiation cross-linking under appropriate conditions. 40 refs

  18. Solid-state polymerisation via [2+2] cycloaddition reaction involving coordination polymers.

    Science.gov (United States)

    Medishetty, Raghavender; Park, In-Hyeok; Lee, Shim Sung; Vittal, Jagadese J

    2016-03-14

    Highly crystalline metal ions containing organic polymers are potentially useful to manipulate the magnetic and optical properties to make advanced multifunctional materials. However, it is challenging to synthesise monocrystalline metal complexes of organic polymers and single-phase hybrid materials made up of both coordination and organic polymers by traditional solution crystallisation. This requires an entirely different approach in the solid-state by thermal or photo polymerisation of the ligands. Among the photochemical methods available, [2+2] cycloaddition reaction has been recently employed to generate cyclobutane based coordination polymers from the metal complexes. Cyclobutane polymers have also been integrated into coordination polymers in this way. Recent advancements in the construction of polymeric chains of cyclobutane rings through photo-dimerisation reaction in the monocrystalline solids containing metal complexes, coordination polymers and metal-organic framework structures are discussed here.

  19. STRUCTURAL AND MECHANICAL CHARACTERIZATION OF DEFORMED POLYMER USING CONFOCAL RAMAN MICROSCOPY AND DSC

    Directory of Open Access Journals (Sweden)

    Birgit Neitzel

    2016-02-01

    Full Text Available Polymers have various interesting properties, which depend largely on their inner structure. One way to influence the macroscopic behaviour is the deformation of the polymer chains, which effects the change in microstructure. For analyzing the microstructure of non-deformed and deformed polymer materials, Raman spectroscopy as well as differential scanning calorimetry (DSC were used. In the present study we compare the results for crystallinity measurements of deformed polymers using both methods in order to characterize the differences in micro-structure due to deformation. The study is ongoing, and we present the results of the first tests.

  20. Impact of solvents and supercritical CO2 drying on the morphology and structure of polymer-based biofilms

    Science.gov (United States)

    Causa, Andrea; Salerno, Aurelio; Domingo, Concepción; Acierno, Domenico; Filippone, Giovanni

    2014-05-01

    In the present work, two-dimensional systems based on biodegradable polymers such as poly(ɛ-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and "green" solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO2. The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material. Conversely, the less crystalline PLA forms almost completely amorphous films.

  1. Impact of solvents and supercritical CO2 drying on the morphology and structure of polymer-based biofilms

    International Nuclear Information System (INIS)

    Causa, Andrea; Acierno, Domenico; Filippone, Giovanni; Salerno, Aurelio; Domingo, Concepción

    2014-01-01

    In the present work, two-dimensional systems based on biodegradable polymers such as poly(ε-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and “green” solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO 2 . The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material. Conversely, the less crystalline PLA forms almost completely amorphous films

  2. Impact of solvents and supercritical CO{sub 2} drying on the morphology and structure of polymer-based biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Causa, Andrea; Acierno, Domenico; Filippone, Giovanni [Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale, Università di Napoli Federico II, Piazzale V. Tecchio, 80, 80125 Napoli (Italy); Salerno, Aurelio; Domingo, Concepción [Instituto de Ciencia de Materiales de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra (Spain)

    2014-05-15

    In the present work, two-dimensional systems based on biodegradable polymers such as poly(ε-caprolactone) (PCL), poly(ethylene oxide) (PEO) and polylactic acid (PLA) are fabricated by means of a sustainable approach which consists in inducing phase separation in solutions of such polymers and “green” solvents, namely ethyl lactate (EL) and ethyl acetate (EA). The extraction of the solvent is promoted by a controlled drying process, which is performed in either air or supercritical CO{sub 2}. The latter can indeed act as both an antisolvent, which favors the deposition of the polymer by forming a mixture with EL and EA, and a plasticizing agent, whose solvation and transport properties may considerably affect the microstructure and crystallinity of the polymer films. The morphological, topographical and crystalline properties of the films are tailored through a judicial selection of the materials and the processing conditions and assessed by means of thermal analyses, polarized optical microscopy, scanning electron microscopy and confocal interferometric microscopy. The results show that the morphological and crystalline properties of the films are strongly dependent on the choice of both the polymer/solvent system and the operating conditions during the drying step. In particular, the morphological, topographical and thermal properties of films prepared starting from highly crystalline polymers, namely PCL and PEO, are greatly affected by the crystallization of the material. Conversely, the less crystalline PLA forms almost completely amorphous films.

  3. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  4. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  5. Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites

    International Nuclear Information System (INIS)

    Chaudhary, D.S.; Prasad, R.; Gupta, R.K.; Bhattacharya, S.N.

    2005-01-01

    Various polymer clay nanocomposites (PCNs) were prepared from ethylene vinyl acetate copolymer (EVA) with 9, 18 and 28% vinyl acetate (VA) content filled with different wt.% (2.5, 5 and 7.5) of a Montmorillonite-based organo-modified clay (Cloisite[reg] C15A and C30B). The PCNs were prepared using melt blending techniques. Morphological information regarding intercalation and exfoliation were determined by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). WAXS and TEM confirmed that increasing the VA content was necessary to achieve greater clay-polymer interaction as seen from the comparatively higher intercalation of clay platelets with 28% VA. The effect of addition of clay on the development and the modification of crystalline morphology in EVA matrix was also studied using WAXS and temperature-modulated differential scanning calorimetry (MDSC). Results are presented showing that the addition of clay platelets does not increase the matrix crystallinity but the morphology was significantly modified such that there was an increase in the 'rigid' amorphous phase. Mechanical properties were also evaluated against the respective morphological information for each specimen and there are indications that the level of clay-polymer interaction plays a significant role in such morphological modification, and in such a way that affects the final PCN mechanical properties which has wide and significant applications in the packaging industries

  6. Injection molding of ceramic filled polypropylene: The effect of thermal conductivity and cooling rate on crystallinity

    International Nuclear Information System (INIS)

    Suplicz, A.; Szabo, F.; Kovacs, J.G.

    2013-01-01

    Highlights: • BN, talc and TiO 2 in 30 vol% were compounded with polypropylene matrix. • According to the DSC measurements, the fillers are good nucleating agents. • The thermal conductivity of the fillers influences the cooling rate of the melt. • The higher the cooling rate is, the lower the crystallinity in the polymer matrix. - Abstract: Three different nano- and micro-sized ceramic powders (boron-nitride (BN), talc and titanium-dioxide (TiO 2 )) in 30 vol% have been compounded with a polypropylene (PP) matrix. Scanning electron microscopy (SEM) shows that the particles are dispersed smoothly in the matrix and larger aggregates cannot be discovered. The cooling gradients and the cooling rate in the injection-molded samples were estimated with numerical simulations and finite element analysis software. It was proved with differential scanning calorimetry (DSC) measurements that the cooling rate has significant influence on the crystallinity of the compounds. At a low cooling rate BN works as a nucleating agent so the crystallinity of the compound is higher than that of unfilled PP. On the other hand, at a high cooling rate, the crystallinity of the compound is lower than that of unfilled PP because of its higher thermal conductivity. The higher the thermal conductivity is, the higher the real cooling rate in the material, which influences the crystallization kinetics significantly

  7. ZnO Coatings with Controlled Pore Size, Crystallinity and Electrical Conductivity

    Directory of Open Access Journals (Sweden)

    Roman SCHMACK

    2016-05-01

    Full Text Available Zinc oxide is a wide bandgap semiconductor with unique optical, electrical and catalytic properties. Many of its practical applications rely on the materials pore structure, crystallinity and electrical conductivity. We report a synthesis method for ZnO films with ordered mesopore structure and tuneable crystallinity and electrical conductivity. The synthesis relies on dip-coating of solutions containing micelles of an amphiphilic block copolymer and complexes of Zn2+ ions with aliphatic ligands. A subsequent calcination at 400°C removes the template and induces crystallization of the pore walls. The pore structure is controlled by the template polymer, whereas the aliphatic ligands control the crystallinity of the pore walls. Complexes with a higher thermal stability result in ZnO films with a higher content of residual carbon, smaller ZnO crystals and therefore lower electrical conductivity. The paper discusses the ability of different types of ligands to assist in the synthesis of mesoporous ZnO and relates the structure and thermal stability of the precursor complexes to the crystallinity and electrical conductivity of the zinc oxide.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.8634

  8. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    Energy Technology Data Exchange (ETDEWEB)

    Puthirath, Anand B.; Varma, Sreekanth J.; Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India); Methattel Raman, Shijeesh [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India)

    2016-04-18

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  9. Comparative Community Proteomics Demonstrates the Unexpected Importance of Actinobacterial Glycoside Hydrolase Family 12 Protein for Crystalline Cellulose Hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Hiras, Jennifer; Wu, Yu-Wei; Deng, Kai; Nicora, Carrie D.; Aldrich, Joshua T.; Frey, Dario; Kolinko, Sebastian; Robinson, Errol W.; Jacobs, Jon M.; Adams, Paul D.; Northen, Trent R.; Simmons, Blake A.; Singer, Steven W.

    2016-08-23

    ABSTRACT

    Glycoside hydrolases (GHs) are key enzymes in the depolymerization of plant-derived cellulose, a process central to the global carbon cycle and the conversion of plant biomass to fuels and chemicals. A limited number of GH families hydrolyze crystalline cellulose, often by a processive mechanism along the cellulose chain. During cultivation of thermophilic cellulolytic microbial communities, substantial differences were observed in the crystalline cellulose saccharification activities of supernatants recovered from divergent lineages. Comparative community proteomics identified a set of cellulases from a population closely related to actinobacteriumThermobispora bisporathat were highly abundant in the most active consortium. Among the cellulases fromT. bispora, the abundance of a GH family 12 (GH12) protein correlated most closely with the changes in crystalline cellulose hydrolysis activity. This result was surprising since GH12 proteins have been predominantly characterized as enzymes active on soluble polysaccharide substrates. Heterologous expression and biochemical characterization of the suite ofT. bisporahydrolytic cellulases confirmed that the GH12 protein possessed the highest activity on multiple crystalline cellulose substrates and demonstrated that it hydrolyzes cellulose chains by a predominantly random mechanism. This work suggests that the role of GH12 proteins in crystalline cellulose hydrolysis by cellulolytic microbes should be reconsidered.

    IMPORTANCECellulose is the most abundant organic polymer on earth, and its enzymatic hydrolysis is a key reaction in the global carbon cycle and the conversion of plant biomass to biofuels. The glycoside hydrolases that depolymerize crystalline cellulose have been primarily characterized from isolates. In this study, we demonstrate that adapting microbial consortia from compost to grow on crystalline cellulose

  10. Irreducible tensor operators and crystalline potentials

    International Nuclear Information System (INIS)

    Boutron, F.; Saint-James, D.

    1961-01-01

    It is often accepted that the effects of its neighbourhood on the quantum state of an ion A may be obtained by the model of the crystalline effective field approximation. Within this assumption Stevens has developed a method which provides equivalent operators that facilitate the calculation of the matrix elements of the crystalline field in a given multiplicity. This method has been extended here. We demonstrate that in the expansion of the crystalline field in powers of the electrons coordinates of the ion A - for electrons of the same sub-shell of A - only even terms can contribute. Equivalent operators and matrix elements, in a given multiplicity, are given for these development terms - up to order 6 - and for potential invariant by the operations of one of the thirty-two point-groups. (author) [fr

  11. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  12. Dynamic mechanical analysis and crystalline analysis of hemp fiber reinforced cellulose filled epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Palanivel, Anand; Duruvasalu, Rajesh; Iyyanar, Saranraj; Velumayil, Ramesh, E-mail: p.anand@ymail.com [Mechanical Engineering, Vel Tech Dr RR. & Dr. SR University, Avadi, Chennai, Tamilnadu (India); Veerabathiran, Anbumalar [Mechanical Engineering, Velammal College of Engineering & Technology, Madurai, TN (India)

    2017-07-01

    The Dynamic mechanical behavior of chemically treated and untreated hemp fiber reinforced composites was investigated. The morphology of the composites was studied to understand the interaction between the filler and polymer. A series of dynamic mechanical tests were performed by varying the fiber loading and test frequencies over a range of testing temperatures. It was found that the storage modulus (E') recorded above the glass transition temperature (Tg) decrease with increasing temperature. The loss modulus (E”) and damping peaks (Tan δ) values were found to be reduced with increasing matrix loading and temperature. Morphological changes and crystallinity of Composites were investigated using scanning electron microscope (SEM) and XRD techniques. The composites with Alkali and Benzoyl treated fibers has attributed enhanced DMA Results. In case of XRD studies, the composites with treated fibers with higher filler content show enhanced crystallinity. (author)

  13. Molecular origins of anisotropic shock propagation in crystalline and amorphous polyethylene

    Science.gov (United States)

    O'Connor, Thomas C.; Elder, Robert M.; Sliozberg, Yelena R.; Sirk, Timothy W.; Andzelm, Jan W.; Robbins, Mark O.

    2018-03-01

    Molecular dynamics simulations are used to analyze shock propagation in amorphous and crystalline polyethylene. Results for the shock velocity Us are compared to predictions from Pastine's equation of state and hydrostatic theory. The results agree with Pastine at high impact velocities. At low velocities the yield stress becomes important, increasing the shock velocity and leading to anisotropy in the crystalline response. Detailed analysis of changes in atomic order reveals the origin of the anisotropic response. For shock along the polymer backbone, an elastic front is followed by a plastic front where chains buckle with a characteristic wavelength. Shock perpendicular to the chain backbone can produce plastic deformation or transitions to different orthorhombic or monoclinic structures, depending on the impact speed and direction. Tensile loading does not produce stable shocks: Amorphous systems craze and fracture while for crystals the front broadens linearly with time.

  14. White emission from liquid-crystalline copolymers containing oxadiazole moieties in the side chain

    Science.gov (United States)

    Kawamoto, Masuki; Tsukamoto, Takuji; Kinoshita, Motoi; Ikeda, Tomiki

    2006-09-01

    A liquid-crystalline polymer in the side chain was synthesized through copolymerization of a bipolar carrier-transporting monomer with a liquid-crystalline monomer containing oxadiazole moieties substituted with trifluoromethyl groups. A single-layer light-emitting diode of indium tin oxide (ITO)/copolymer/MgAg emitted white light with a maximum luminous efficiency of 0.1cd/A. The origin of the white emission in the copolymer is the electroplex between bipolar carrier-transporting moieties and strong electron-withdrawing moieties. Furthermore, a simple multilayer device with configuration of ITO/poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid)/copolymer/MgAg device showed white emission with CIE 1931 chromaticity coordinates (x,y): (0.30, 0.33).

  15. Dynamic mechanical analysis and crystalline analysis of hemp fiber reinforced cellulose filled epoxy composite

    Directory of Open Access Journals (Sweden)

    Anand Palanivel

    Full Text Available Abstract The Dynamic mechanical behavior of chemically treated and untreated hemp fiber reinforced composites was investigated. The morphology of the composites was studied to understand the interaction between the filler and polymer. A series of dynamic mechanical tests were performed by varying the fiber loading and test frequencies over a range of testing temperatures. It was found that the storage modulus (E’ recorded above the glass transition temperature (Tg decrease with increasing temperature. The loss modulus (E” and damping peaks (Tan δ values were found to be reduced with increasing matrix loading and temperature. Morphological changes and crystallinity of Composites were investigated using scanning electron microscope (SEM and XRD techniques. The composites with Alkali and Benzoyl treated fibers has attributed enhanced DMA Results. In case of XRD studies, the composites with treated fibers with higher filler content show enhanced crystallinity.

  16. Shape-memory effect of nanocomposites based on liquid-crystalline elastomers

    Science.gov (United States)

    Marotta, A.; Lama, G. C.; Gentile, G.; Cerruti, P.; Carfagna, C.; Ambrogi, V.

    2016-05-01

    In this work, nanocomposites based on liquid crystalline (LC) elastomers were prepared and characterized in their shape memory properties. For the synthesis of materials, p-bis(2,3-epoxypropoxy)-α-methylstilbene (DOMS) was used as mesogenic epoxy monomer, sebacic acid (SA) as curing agent and multi-walled carbon nanotubes (MWCNT) and graphene oxide (GO) as fillers. First, an effective compatibilization methodology was set up to improve the interfacial adhesion between the matrix and the carbonaceous nanofillers, thus obtaining homogeneous distribution and dispersion of the nanofillers within the polymer phase. Then, the obtained nanocomposite films were characterized in their morphological and thermal properties. In particular, the effect of the addition of the nanofillers on liquid crystalline behavior, as well as on shape-memory properties of the realized materials was investigated. It was found that both fillers were able to enhance the thermomechanical response of the LC elastomers, making them good candidates as shape memory materials.

  17. Effect of time and temperature exposition in the crystallinity degree of sulfonated poly-(styrene acrylic acid) (PSAA-S)

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, G.W.; Becker, E.B.; Silva, L.; Naspolini, A.M.; Consenso, E.C.; Paula, M.M.S.; Fiori, M.A., E-mail: glau_bn@hotmail.co [University of Extreme South of Santa Catarina Criciuma, SC (Brazil). Dept. of Materials Engineering; Silveira, F.Z. [Federal University of Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. of Chemical Engineering

    2010-07-01

    Polymers with special properties have been increasingly applied in the development of technological devices. For example, polymeric materials with special electric properties, such as sulfonated poly-(styrene-acrylic acid) - PSAA-S, are of great interest for showing different conductivities depending on the environment where they are applied. The special properties of PSAA are obtained only after sulfonation step in acidic media. The present work aimed to evaluate the effect of time and temperature exposition in the crystallinity degree of PSAA-S, through a statistical experimental factorial planning. The samples of PSAA-S were submitted to FT-IR and DRX tests. The results showed that the temperature and the time of exposition are significant factors in the crystallinity degree of PSAA-S, considering that the crystal lattices created during the polymerization are damaged by the action of time and temperature at which the polymer is exposed. (author)

  18. Effect of time and temperature exposition in the crystallinity degree of sulfonated poly-(styrene acrylic acid) (PSAA-S)

    International Nuclear Information System (INIS)

    Duarte, G.W.; Becker, E.B.; Silva, L.; Naspolini, A.M.; Consenso, E.C.; Paula, M.M.S.; Fiori, M.A.; Silveira, F.Z.

    2010-01-01

    Polymers with special properties have been increasingly applied in the development of technological devices. For example, polymeric materials with special electric properties, such as sulfonated poly-(styrene-acrylic acid) - PSAA-S, are of great interest for showing different conductivities depending on the environment where they are applied. The special properties of PSAA are obtained only after sulfonation step in acidic media. The present work aimed to evaluate the effect of time and temperature exposition in the crystallinity degree of PSAA-S, through a statistical experimental factorial planning. The samples of PSAA-S were submitted to FT-IR and DRX tests. The results showed that the temperature and the time of exposition are significant factors in the crystallinity degree of PSAA-S, considering that the crystal lattices created during the polymerization are damaged by the action of time and temperature at which the polymer is exposed. (author)

  19. The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

    KAUST Repository

    Oh, Jae Eun; Monteiro, Paulo J.M.; Jun, Ssang Sun; Choi, Sejin; Clark, Simon M.

    2010-01-01

    The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order

  20. Used fuel disposition in crystalline rocks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kalinina, Elena Arkadievna [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Buck, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Eittman, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tinnacher, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tournassat, Christophe. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Viswanathan, H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-01

    The U.S. Department of Energy Office of Nuclear Energy, Office of Fuel Cycle Technology established the Used Fuel Disposition Campaign (UFDC) in fiscal year 2010 (FY10) to conduct the research and development (R&D) activities related to storage, transportation and disposal of used nuclear fuel and high level nuclear waste. The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media.

  1. Irradiation induced crystalline to amorphous transition

    International Nuclear Information System (INIS)

    Bourgoin, J.

    1980-01-01

    Irradiation of a crystalline solid with energetic heavy particles results in cascades of defects which, with increasing dose, overlap and form a continuous disordered layer. In semiconductors the physical properties of such disordered layers are found to be similar to those of amorphous layers produced by evaporation. It is shown in the case of silicon, that the transition from a disordered crystalline (X) layer to an amorphous (α) layer occurs when the Gibbs energy of the X phase and of the defects it contains becomes larger than the Gibbs energy of the α phase. (author)

  2. Electronic processes in non-crystalline materials

    CERN Document Server

    Mott, Nevill Francis

    2012-01-01

    Since the first edition of this highly successful book the field saw many great developments both in experimental and theoretical studies of electrical properties of non-crystalline solids. It became necessary to rewrite nearly the whole book, while the aims of the second edition remained the same: to set out the theoretical concepts, to test them by comparison with experiment for a wide variety of phenomena, and to apply them to non-crystalline materials. Sir Nevill Mott shared the1977 Nobel Prize for Physics, awarded for his research work in this field. The reissue of this book as part of th

  3. Deuteron NMR and modelling in solid polymers

    International Nuclear Information System (INIS)

    Hirschinger, J.

    1992-01-01

    Deuteron NMR techniques are described and some recent applications to the study of rotational motions in solid polymers are reviewed. The information content and the domain of applicability of each technique are presented. Ultra-slow motions are studied in real time without any motional model consideration. For very fast motions, computer molecular dynamics simulations are shown to complement the NMR results. Experimental examples deal with the chain motion in the crystalline α-phase of poly(vinylidenefluoride) and nylon 6,6

  4. Effects of thermal ageing on HMS-PP crystallinity

    International Nuclear Information System (INIS)

    Oliani, Washington L.; Parra, Duclerc F.; Lima, Luis F.C.P.; Lugao, Ademar B.

    2009-01-01

    The isotactic polypropylene is a linear polymer which exhibits low melt strength. Irradiation of PP under inert atmosphere causes a combination of chain scissioning and long-chain branching, and results in a material with significant enhanced melt strength. This process, which is sometimes termed visbreaking, thus provides improvement of rheological properties. HMS-PP (High Melt Strength Polypropylene) was obtained by the irradiation in atmosphere of acetylene as crosslinker agent. It was employed doses of 12.5 and 20 kGy of gamma radiation. The objective of this study is to investigate the effects of thermal ageing on the crystallinity level and chemical structure of HMS-PP. The thermal stability of the HMS-PP was evaluated after thermal ageing of samples using a stove at temperature of 90 deg C, in presence of air at different periods of time. The samples submitted to the thermal ageing were characterized by: thermogravimetry (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Since the long-term engineering properties of HMS-PP are intrinsically linked with the polymer microstructure, there is significant interest in understanding the effects of ageing, particularly due to prolonged exposure at service temperatures. In thermo-oxidative conditions, the formation of the oxidation products essentially involves a hydrogen abstraction by the peroxyl radicals, leading to hydroperoxides as primary products and chemical degradation in the immediate crack tips. Oxidative degradation on the network of HMS-PP, created by radiation process of PP, was revealed by the analytical results showing the susceptibility of HMS-PP to thermal oxidative degradation. Yellowing of the samples surface and oxidative products of degradation among other evidences were observed. (author)

  5. Polymer - (BEDT-TTF) polyiodide composites

    Energy Technology Data Exchange (ETDEWEB)

    Ulanski, J [Polymer Inst., Technical Univ. of Lodz (Poland); Glowacki, I [Polymer Inst., Technical Univ. of Lodz (Poland); Kryszewski, M [Polymer Inst., Technical Univ. of Lodz (Poland); Jeszka, J K [Center of Molecular and Macromolecular Studies, Lodz (Poland); Tracz, A [Center of Molecular and Macromolecular Studies, Lodz (Poland); Laukhina, E [Inst. of Chemical Physics, Chernogolovka (Russian Federation)

    1993-03-29

    Preparation and properties of reticulate doped polymers containing BEDT-TTF polyiodide crystalline network are discussed. The highly conducting films are obtained using different methods, including recently developed one in which oxidation of the donor with iodine and crystallization of the resulting salt take place simultaneously in situ, in the swollen polymer matrix. It was found that the temperature dependence of conductivity of the separated microcrystal grown in the film exhibits metallic character with a maximum around 100K. The conductivity of the as-obtained composite increases with temperature up to ca. 120K with an activation energy of ca. 50 meV, then levels off. Annealing of the composites in order to transform the BEDT-TTF polyiodide crystalites into superconducting [beta][sup *]-phase causes dramatic changes in the conductivity behaviour; the [sigma](T) dependence of the composite switches from semiconductor- to metal-like. Stability of the films at ambient conditions is good. (orig.)

  6. Temperature dependence of radiation chemistry of polymers

    International Nuclear Information System (INIS)

    Garrett, R.W.; Hill, D.J.T.; Le, T.T.; Milne, K.A.; O'Donnell, J.H.; Perera, S.M.C.; Pomery, P.J.

    1990-01-01

    Chemical reactions which occur during radiolysis of polymers usually show an increase in rate with increasing temperature that can be described by an Arrhenius relationship. The magnitude of the activation energy can vary widely and is affected by physical, as well as chemical, factors. Different reaction rates may be expected in crystalline and amorphous morphologies, and in glassy and rubbery regions. The temperature dependence of radiolysis reactions can be expected to show discontinuities at the glass and melting transitions, T g and T m . The ceiling temperature, T c , for polymerization/depolymerization will also affect the rate of degradation, especially for depropagation to monomer. The temperature for this effect depends on the molecular structure of the polymer. The temperature dependence of free radical reactions can be studied by cryogenic trapping and ESR spectroscopy during thermal profiling. Increased degradation rates at high dose rates can be due to increased temperatures resulting from energy absorption

  7. Novel Polymer Architectures for Optical Storage

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Forcén, Patrica; Oriol, Luis

    2007-01-01

    Azobenzene containing polymers have been shown to have a large potential for high capacity olographic information storage. However, it has been difficult to fabricate thick films of the polymers with good op~ical quality so far. Liquid crystalline block copolymers prepared by Atom Transfer Radical...... Polymerization and based on azobenzene methacrylate and methyl methacrylate show some promise due to the observed block segregation. Thus, lamellar nanostructure was observed'when the azobenzene content was > 20% by weight, and both birefringence and dichroism can be induced by linearly polarized 488 nm light....... The formation of azo-aggregation inside the azo blocks is strongly,reduced when going from the homopolymer to the copolymers....

  8. Twinning of Polymer Crystals Suppressed by Entropy

    Directory of Open Access Journals (Sweden)

    Nikos Ch. Karayiannis

    2014-09-01

    Full Text Available We propose an entropic argument as partial explanation of the observed scarcity of twinned structures in crystalline samples of synthetic organic polymeric materials. Polymeric molecules possess a much larger number of conformational degrees of freedom than low molecular weight substances. The preferred conformations of polymer chains in the bulk of a single crystal are often incompatible with the conformations imposed by the symmetry of a growth twin, both at the composition surfaces and in the twin axis. We calculate the differences in conformational entropy between chains in single crystals and chains in twinned crystals, and find that the reduction in chain conformational entropy in the twin is sufficient to make the single crystal the stable thermodynamic phase. The formation of cyclic twins in molecular dynamics simulations of chains of hard spheres must thus be attributed to kinetic factors. In more realistic polymers this entropic contribution to the free energy can be canceled or dominated by nonbonded and torsional energetics.

  9. A flexible liquid crystal polymer MEMS pressure sensor array for fish-like underwater sensing

    International Nuclear Information System (INIS)

    Kottapalli, A G P; Asadnia, M; Miao, J M; Barbastathis, G; Triantafyllou, M S

    2012-01-01

    In order to perform underwater surveillance, autonomous underwater vehicles (AUVs) require flexible, light-weight, reliable and robust sensing systems that are capable of flow sensing and detecting underwater objects. Underwater animals like fish perform a similar task using an efficient and ubiquitous sensory system called a lateral-line constituting of an array of pressure-gradient sensors. We demonstrate here the development of arrays of polymer microelectromechanical systems (MEMS) pressure sensors which are flexible and can be readily mounted on curved surfaces of AUV bodies. An array of ten sensors with a footprint of 60 (L) mm × 25 (W) mm × 0.4 (H) mm is fabricated using liquid crystal polymer (LCP) as the sensing membrane material. The flow sensing and object detection capabilities of the array are illustrated with proof-of-concept experiments conducted in a water tunnel. The sensors demonstrate a pressure sensitivity of 14.3 μV Pa −1 . A high resolution of 25 mm s −1 is achieved in water flow sensing. The sensors can passively sense underwater objects by transducing the pressure variations generated underwater by the movement of objects. The experimental results demonstrate the array’s ability to detect the velocity of underwater objects towed past by with high accuracy, and an average error of only 2.5%. (paper)

  10. Determination of crystallinity of ceramic materials from the Ruland Method

    International Nuclear Information System (INIS)

    Kniess, C.T.; Prates, P.B.; Gomes Junior, J.C.; Lima, J.C. de; Riella, H.G.; Kuhnen, N.C.

    2011-01-01

    Some methods found in literature approach the different characteristics between crystalline and amorphous phases by X ray diffraction technique. These methods use the relation between the intensities of the crystalline peaks and background amorphous or the absolute intensity of one of these to determine the relative amount of crystalline and amorphous material. However, a crystalline substance presents shows coherent diffuse scattering and a loss in the intensity of the peaks of diffraction in function of thermal vibrations of atoms and imperfections in the crystalline structure. A correct method for the determination of the crystallinity must take in account these effects. This work has as objective to determine the crystallinity of ceramic materials obtained with the addition of mineral coal bottom ashes, using the X ray diffraction technique and the Ruland Method, that considers the diminution of the intensity of the crystalline peak because of the disorder affects. The Ruland Method shows adequate for the determination of the crystallinity of the ceramic materials. (author)

  11. Alignment engineering in liquid crystalline elastomers: Free-form microstructures with multiple functionalities

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Hao; Cerretti, Giacomo; Wiersma, Diederik S., E-mail: camilla.parmeggiani@lens.unifi.it, E-mail: wiersma@lens.unifi.it [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Wasylczyk, Piotr [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Faculty of Physics, Institute of Experimental Physics, University of Warsaw, ul. Hoza 69, Warszawa 00-681 (Poland); Martella, Daniele [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); Dipartimento di Chimica “Ugo Schiff,” University of Florence, via della Lastruccia 3-13, 50019 Sesto Fiorentino (Italy); Parmeggiani, Camilla, E-mail: camilla.parmeggiani@lens.unifi.it, E-mail: wiersma@lens.unifi.it [European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy); CNR-INO, via Nello Carrara 1, 50019 Sesto Fiorentino (Italy)

    2015-03-16

    We report a method to fabricate polymer microstructures with local control over the molecular orientation. Alignment control is achieved on molecular level in a structure of arbitrary form that can be from 1 to 100 μm in size, by fixing the local boundary conditions with micro-grating patterns. The method makes use of two-photon polymerization (Direct Laser Writing) and is demonstrated specifically in liquid-crystalline elastomers. This concept allows for the realization of free-form polymeric structures with multiple functionalities which are not possible to realize with existing techniques and which can be locally controlled by light in the micrometer scale.

  12. Metamict state radiation damage in crystalline materials

    International Nuclear Information System (INIS)

    Haaker, R.F.; Ewing, R.C.

    1979-01-01

    Metamict minerals provide an excellent basis for the evaluation of long-term radiation damage effects, particularly such changes in physical and chemical properties as microfracturing, hydrothermal alteration, and solubility. This paper summarizes pertinent literature on metamictization and proposes experiments that are critical to the elucidation of structural controls on radiation damage in crystalline phases

  13. Crystalline amino acids and nitrogen emission

    NARCIS (Netherlands)

    Verstegen, M.W.A.; Jongbloed, A.W.

    2003-01-01

    Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig

  14. Attenuation of Thermal Neutrons by Crystalline Silicon

    International Nuclear Information System (INIS)

    Adib, M.; Habib, N.; Ashry, A.; Fathalla, M.

    2002-01-01

    A simple formula is given which allows to calculate the contribution of the total neutron cross - section including the Bragg scattering from different (hkt) planes to the neutron * transmission through a solid crystalline silicon. The formula takes into account the silicon form of poly or mono crystals and its parameters. A computer program DSIC was developed to provide the required calculations. The calculated values of the total neutron cross-section of perfect silicon crystal at room and liquid nitrogen temperatures were compared with the experimental ones. The obtained agreement shows that the simple formula fits the experimental data with sufficient accuracy .A good agreement was also obtained between the calculated and measured values of polycrystalline silicon in the energy range from 5 eV to 500μ eV. The feasibility study on using a poly-crystalline silicon as a cold neutron filter and mono-crystalline as a thermal neutron one is given. The optimum crystal thickness, mosaic spread, temperature and cutting plane for efficiently transmitting the thermal reactor neutrons, while rejecting both fast neutrons and gamma rays accompanying the thermal ones for the mono crystalline silicon are also given

  15. Growing perovskite into polymers for easy-processable optoelectronic devices

    Science.gov (United States)

    Masi, Sofia; Colella, Silvia; Listorti, Andrea; Roiati, Vittoria; Liscio, Andrea; Palermo, Vincenzo; Rizzo, Aurora; Gigli, Giuseppe

    2015-01-01

    Here we conceive an innovative nanocomposite to endow hybrid perovskites with the easy processability of polymers, providing a tool to control film quality and material crystallinity. We verify that the employed semiconducting polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), controls the self-assembly of CH3NH3PbI3 (MAPbI3) crystalline domains and favors the deposition of a very smooth and homogenous layer in one straightforward step. This idea offers a new paradigm for the implementation of polymer/perovskite nanocomposites towards versatile optoelectronic devices combined with the feasibility of mass production. As a proof-of-concept we propose the application of such nanocomposite in polymer solar cell architecture, demonstrating a power conversion efficiency up to 3%, to date the highest reported for MEH-PPV. On-purpose designed polymers are expected to suit the nanocomposite properties for the integration in diverse optoelectronic devices via facile processing condition.

  16. Gamma crystallins of the human eye lens.

    Science.gov (United States)

    Vendra, Venkata Pulla Rao; Khan, Ismail; Chandani, Sushil; Muniyandi, Anbukkarasi; Balasubramanian, Dorairajan

    2016-01-01

    Protein crystallins co me in three types (α, β and γ) and are found predominantly in the eye, and particularly in the lens, where they are packed into a compact, plastic, elastic, and transparent globule of proper refractive power range that aids in focusing incoming light on to the retina. Of these, the γ-crystallins are found largely in the nuclear region of the lens at very high concentrations (>400 mg/ml). The connection between their structure and inter-molecular interactions and lens transparency is an issue of particular interest. We review the origin and phylogeny of the gamma crystallins, their special structure involving the use of Greek key supersecondary structural motif, and how they aid in offering the appropriate refractive index gradient, intermolecular short range attractive interactions (aiding in packing them into a transparent ball), the role that several of the constituent amino acid residues play in this process, the thermodynamic and kinetic stability and how even single point mutations can upset this delicate balance and lead to intermolecular aggregation, forming light-scattering particles which compromise transparency. We cite several examples of this, and illustrate this by cloning, expressing, isolating and comparing the properties of the mutant protein S39C of human γS-crystallin (associated with congenital cataract-microcornea), with those of the wild type molecule. In addition, we note that human γ-crystallins are also present in other parts of the eye (e.g., retina), where their functions are yet to be understood. There are several 'crucial' residues in and around the Greek key motifs which are essential to maintain the compact architecture of the crystallin molecules. We find that a mutation that replaces even one of these residues can lead to reduction in solubility, formation of light-scattering particles and loss of transparency in the molecular assembly. Such a molecular understanding of the process helps us construct the

  17. Effects of Confinement on Microstructure and Charge Transport in High Performance Semicrystalline Polymer Semiconductors

    KAUST Repository

    Himmelberger, Scott; Dacuñ a, Javier; Rivnay, Jonathan; Jimison, Leslie H.; McCarthy-Ward, Thomas; Heeney, Martin; McCulloch, Iain; Toney, Michael F.; Salleo, Alberto

    2012-01-01

    The film thickness of one of the most crystalline and highest performing polymer semiconductors, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] thiophene) (PBTTT), is varied in order to determine the effects of interfaces and confinement on the microstructure and performance in organic field effect transistors (OFETs). Crystalline texture and overall film crystallinity are found to depend strongly on film thickness and thermal processing. The angular distribution of crystallites narrows upon both a decrease in film thickness and thermal annealing. These changes in the film microstructure are paired with thin-film transistor characterization and shown to be directly correlated with variations in charge carrier mobility. Charge transport is shown to be governed by film crystallinity in films below 20 nm and by crystalline orientation for thicker films. An optimal thickness is found for PBTTT at which the mobility is maximized in unannealed films and where mobility reaches a plateau at its highest value for annealed films. The effects of confinement on the morphology and charge transport properties of poly(2,5-bis(3-tetradecylthiophen-2-yl) thieno[3,2-b]thiophene) (PBTTT) are studied using quantitative X-ray diffraction and field-effect transistor measurements. Polymer crystallinity is found to limit charge transport in the thinnest films while crystalline texture and intergrain connectivity modulate carrier mobility in thicker films. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Effects of Confinement on Microstructure and Charge Transport in High Performance Semicrystalline Polymer Semiconductors

    KAUST Repository

    Himmelberger, Scott

    2012-11-23

    The film thickness of one of the most crystalline and highest performing polymer semiconductors, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] thiophene) (PBTTT), is varied in order to determine the effects of interfaces and confinement on the microstructure and performance in organic field effect transistors (OFETs). Crystalline texture and overall film crystallinity are found to depend strongly on film thickness and thermal processing. The angular distribution of crystallites narrows upon both a decrease in film thickness and thermal annealing. These changes in the film microstructure are paired with thin-film transistor characterization and shown to be directly correlated with variations in charge carrier mobility. Charge transport is shown to be governed by film crystallinity in films below 20 nm and by crystalline orientation for thicker films. An optimal thickness is found for PBTTT at which the mobility is maximized in unannealed films and where mobility reaches a plateau at its highest value for annealed films. The effects of confinement on the morphology and charge transport properties of poly(2,5-bis(3-tetradecylthiophen-2-yl) thieno[3,2-b]thiophene) (PBTTT) are studied using quantitative X-ray diffraction and field-effect transistor measurements. Polymer crystallinity is found to limit charge transport in the thinnest films while crystalline texture and intergrain connectivity modulate carrier mobility in thicker films. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Characterization and use of crystalline bacterial cell surface layers

    Science.gov (United States)

    Sleytr, Uwe B.; Sára, Margit; Pum, Dietmar; Schuster, Bernhard

    2001-10-01

    Crystalline bacterial cell surface layers (S-layers) are one of the most common outermost cell envelope components of prokaryotic organisms (archaea and bacteria). S-layers are monomolecular arrays composed of a single protein or glycoprotein species and represent the simplest biological membranes developed during evolution. S-layers as the most abundant of prokaryotic cellular proteins are appealing model systems for studying the structure, synthesis, genetics, assembly and function of proteinaceous supramolecular structures. The wealth of information existing on the general principle of S-layers have revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) functional groups on the surface and in the pores are aligned in well-defined positions and orientations and accessible for chemical modifications and binding functional molecules in very precise fashion; (iii) isolated S-layer subunits from a variety of organisms are capable of recrystallizing as closed monolayers onto solid supports (e.g., metals, polymers, silicon wafers) at the air-water interface, on lipid films or onto the surface of liposomes; (iv) functional domains can be incorporated in S-layer proteins by genetic engineering. Thus, S-layer technologies particularly provide new approaches for biotechnology, biomimetics, molecular nanotechnology, nanopatterning of surfaces and formation of ordered arrays of metal clusters or nanoparticles as required for nanoelectronics.

  20. Efectos de la calidad sanitaria de la caña semilla en los componentes del rendimiento cultural de las variedades CP 65-357 y LCP 85-384 (Saccharum spp., según diferentes edades de corte (Parte 2 Effects of seedcane quality on yielding components of CP 65-357 and LCP 85-384 (Saccharum spp. varieties at different crop ages (Part 2

    Directory of Open Access Journals (Sweden)

    María B. García

    2011-12-01

    Full Text Available Tradicionalmente, la mayoría de los productores de caña de azúcar de Tucumán utilizó en sus plantaciones, caña semilla proveniente de lotes comerciales con elevada infección de RSD (del inglés "ratoon stunting disease". Esta enfermedad sistémica, causada por Leifsonia xyli subsp. xyli, es ampliamente reconocida por su efecto detrimental sobre el rendimiento cultural. Desde hace pocos años, la disponibilidad de caña semilla saneada hizo viable la incorporación de cambios fundamentales en las prácticas culturales, que posibilitan aumentar la productividad de los cañaverales tucumanos. El objetivo del presente trabajo fue cuantificar el efecto de la calidad sanitaria de la caña semilla sobre el rendimiento cultural y sus componentes en dos variedades comerciales, LCP 85-384 y CP 65-357, a través de seis edades de corte. Este trabajo complementa la información obtenida para las tres primeras edades de corte, ya publicada. Se evaluaron dos calidades de caña semilla: semilla de alta calidad (SAC, saneada por cultivo de meristemas y multiplicada por propagación in vitro, y semilla comercial (SC infectada con RSD. Los tratamientos se implantaron en un diseño en bloques completos al azar con seis repeticiones. En cada edad se evaluaron: número de tallos/ parcela y peso, altura y diámetro de los tallos. Mediante el análisis de la varianza y pruebas de comparación de medias (DMS de Fisher, se determinó que la calidad sanitaria de la semilla afecta los componentes del rendimiento cultural. Se verificaron diferencias a favor de la semilla SAC para peso y altura de los tallos y, en menor medida, para número de tallos. El diámetro de los tallos no resultó afectado por la calidad de la semilla. Para cada edad, se registraron importantes disminuciones en la producción de caña/ha en los tratamientos provenientes de SC respecto a los originados de SAC. Considerando la producción acumulada en las seis cosechas (planta a soca 5, los

  1. Study of photoconductor polymers synthesized by plasma

    International Nuclear Information System (INIS)

    Enriquez P, M.A.

    2007-01-01

    In this work the photoconductivity in poly thiophene (PTh), poly pyrrole (PPy) and doped poly pyrrole with iodine (PPy/I) is studied, whose structures depend of the intensity of the electric field applied during the synthesis by plasma. The conjugated organic polymers possess double alternated bonds in its chemical structure that its allow the one movement of π electrons through the polymeric chains. The plasma is produced by means of splendor discharges to 13.5 MHz, resistive coupling, at one pressure that oscillates in the interval from 2 to 3x10 -1 mbar, 180 min and powers of 10, 24, 40, 60 , 80 and 100 W. Its were used heteroaromatic polymers like PTh and PPy/I, due to their potential applications in optoelectronics. The influence of the iodine is evaluated as dopant in PPy and it is compared with their similar one without doping in the light absorption/emission processes. The polymers synthesized by plasma can ramify or to intersect due to the energy applied during the synthesis. However, if the polymer intersects, the aromaticity can continue through the polymeric chains. The absorptions obtained by infrared spectroscopy, suggest that the polymer conserves the aromatic structure of the monomer fundamentally with substitutions that indicate inter crossing and partial fragmentation. The structure of most of the polymers spreads to be amorphous because they don't possess any classification. However, the PPy/I and PTh synthesized by this technique present crystalline segments whose intensity diminishes with the power of the discharge. In PTh, the average crystallinity diminishes from 19.8% to 9.9%, and in PPy/I of 15.9% to 13.3% in the interval of 10 to 100 W of power. In this work, however, its were crystalline arrangements in all the studied powers. The classification of the polymeric structure favors the formation of trajectories of transfer of electric loads among the chains, that which influences in the global electric conductivity of the material. In UV

  2. Effect of ionizing and nonionizing radiations on the mechanical properties of cellulose tri acetate polymer

    Energy Technology Data Exchange (ETDEWEB)

    Sallam, M M; El-Fiki, S A; Nooh, S A [Physics Department, Faculty of Science, Ain Chams Univ, Cairo (Egypt); Eissa, H M [National Institute for Standard, Cairo (Egypt)

    1997-12-31

    Several quantities including modulus of elasticity, fracture stress, fracture strain, yield tress and yield strain, were calculated for cellulose tri acetate polymer. These samples were exposed to different gamma doses in the range from (32 kg y), and different energies of infrared pulsated laser of 5 watt power in the range (Zero to 9 j/cm 2). The changes in these parameters were found to be due to changes in degree of crystallinity of polymers.4 figs., 3 tabs.

  3. Preparation and Characterization of PVA Alkaline Solid Polymer Electrolyte with Addition of Bamboo Charcoal

    OpenAIRE

    Lidan Fan; Mengyue Wang; Zhen Zhang; Gang Qin; Xiaoyi Hu; Qiang Chen

    2018-01-01

    Natural bamboo charcoal (BC) powder has been developed as a novel filler in order to further improve performances of the polyvinyl alcohol (PVA)-based alkaline solid polymer electrolyte (ASPE) by solution casting method. X-ray diffraction patterns of composite polymer electrolyte with BC revealed the decrease in the degree of crystallinity with increasing content of BC. Scanning electron microscopy images showed pores on a micrometer scale (average diameter about 2 μm) distributed inside a...

  4. Theoretical predictions of diffusion from Brownian motion in superstrong polymers

    International Nuclear Information System (INIS)

    Dowell, F.

    1991-01-01

    This paper presents a summary of unique highly nonlinear static and dynamic theories for chain molecules (actually, for almost any kind of organic molecule), including the first superstrong polymers. These theories have been used to predict and explain (1) the physical self-assembly (self-ordering) of specific kinds of molecules into liquid crystalline (LC) phases (i.e., partially ordered phases) and (2) the diffusion of these molecules in various LC phases and the isotropic (I) liquid phase

  5. Selectivity of radiation-induced processes in hydrocarbons, related polymers and organized polymer systems

    International Nuclear Information System (INIS)

    Feldman, V.I.; Sukhov, F.F.; Zezin, A.A.; Orlov, A.Yu.

    1999-01-01

    Fundamental aspects of the selectivity of radiation-induced events in polymers and polymeric systems were considered: (1) The grounds of selectivity of the primary events were analyzed on the basis of the results of studies of model compounds (molecular aspect). Basic results were obtained for hydrocarbon molecules irradiated in low-temperature matrices. The effects of selective localization of the primary events on the radical formation were examined for several polymers irradiated at low and superlow temperatures (77 and 15 K). A remarkable correlation between the properties of prototype ionized molecules (radical cations) and selectivity of the primary bond rupture in the corresponding polymers were found for polyethylene, polystyrene and some other hydrocarbon polymers. The first direct indication of selective localization of primary events at conformational defects was obtained for oriented high-crystalline polyethylene irradiated at 15 K. The significance of dimeric ring association was proved for the radiation chemistry of polystyrene. Specific mechanisms of low-temperature radiation-induced degradation were also analyzed for polycarbonate and poly(alkylene terephthalates). (2) Specific features of the localization of primary radiation-induced events in microheterogeneous polymeric systems were investigated (microstructural aspect). It was found that the interphase processes played an important role in the radiation chemistry of such systems. The interphase electron migration may result in both positive and negative non-additive effects in the formation of radiolysis products. The effects of component diffusion and chemical reactions on the radiation-induced processes in microheterogeneous polymeric systems were studied with the example of polycarbonate - poly(alkylene terephthalate) blends. (3) The effects of restricted molecular motion on the development of the radiation-chemical processes in polymers were investigated (dynamic aspect). In particular, it

  6. Microgel polymer composite fibres

    OpenAIRE

    Kehren, Dominic

    2014-01-01

    In this thesis some novel ideas and advancements in the field of polymer composite fibres, specifically microgel-based polymer composite fibres have been achieved. The main task was to investigate and understand the electrospinning process of microgels and polymers and the interplay of parameter influences, in order to fabricate reproducible and continuously homogenous composite fibres. The main aim was to fabricate a composite material which combines the special properties of polymer fibres ...

  7. The equilibrium theory of inhomogeneous polymers (international series of monographs on physics)

    CERN Document Server

    Fredrickson, Glenn

    2013-01-01

    The Equilibrium Theory of Inhomogeneous Polymers provides an introduction to the field-theoretic methods and computer simulation techniques that are used in the design of structured polymeric fluids. By such methods, the principles that dictate equilibrium self-assembly in systems ranging from block and graft copolymers, to polyelectrolytes, liquid crystalline polymers, and polymer nanocomposites can be established. Building on an introductory discussion of single-polymer statistical mechanics, the book provides a detailed treatment of analytical and numerical techniques for addressing the conformational properties of polymers subjected to spatially-varying potential fields. This problem is shown to be central to the field-theoretic description of interacting polymeric fluids, and models for a number of important polymer systems are elaborated. Chapter 5 serves to unify and expound the topic of self-consistent field theory, which is a collection of analytical and numerical techniques for obtaining solutions o...

  8. Thermosetting Phthalocyanine Polymers

    Science.gov (United States)

    Fohlen, G.; Parker, J.; Achar, B.

    1985-01-01

    Group of phthalocyanine polymers resist thermal degradation. Polymers expected semiconducting. Principal applications probably in molded or laminated parts that have to withstand high temperatures. Polymers made from either of two classes of monomer: Bisphthalonitriles with imide linkages or Bisphthalonitriles with ester-imide linkages.

  9. based gel polymer electrolytes

    Indian Academy of Sciences (India)

    (PVdF) as a host polymer, lithium perchlorate (LiClO4), lithium triflate ... TG/DTA studies showed the thermal stability of the polymer electrolytes. .... are observed while comparing pure XRD spectra with .... batteries as its operating temperature is normally in the .... chain ion movements and the conductivity of the polymer.

  10. Aerogel / Polymer Composite Materials

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2017-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  11. A non-invasive experimental approach for surface temperature measurements on semi-crystalline thermoplastics

    Science.gov (United States)

    Boztepe, Sinan; Gilblas, Remi; de Almeida, Olivier; Le Maoult, Yannick; Schmidt, Fabrice

    2017-10-01

    Most of the thermoforming processes of thermoplastic polymers and their composites are performed adopting a combined heating and forming stages at which a precursor is heated prior to the forming. This step is done in order to improve formability by softening the thermoplastic polymer. Due to low thermal conductivity and semi-transparency of polymers, infrared (IR) heating is widely used for thermoforming of such materials. Predictive radiation heat transfer models for temperature distributions are therefore critical for optimizations of thermoforming process. One of the key challenges is to build a predictive model including the physical background of radiation heat transfer phenomenon in semi-crystalline thermoplastics as their microcrystalline structure introduces an optically heterogeneous medium. In addition, the accuracy of a predictive model is required to be validated experimentally where IR thermography is one of the suitable methods for such a validation as it provides a non-invasive, full-field surface temperature measurement. Although IR cameras provide a non-invasive measurement, a key issue for obtaining a reliable measurement depends on the optical characteristics of a heated material and the operating spectral band of IR camera. It is desired that the surface of a material to be measured has a spectral band where the material behaves opaque and an employed IR camera operates in the corresponding band. In this study, the optical characteristics of the PO-based polymer are discussed and, an experimental approach is proposed in order to measure the surface temperature of the PO-based polymer via IR thermography. The preliminary analyses showed that IR thermographic measurements may not be simply performed on PO-based polymers and require a correction method as their semi-transparent medium introduce a challenge to obtain reliable surface temperature measurements.

  12. Liquid Crystalline Perylene diimides : Architecture and Charge Carrier Mobilities

    NARCIS (Netherlands)

    Struijk, C.W.; Sieval, A.B.; Dakhorst, J.E.J.; Dijk, van M.; Kimkes, P.; Koehorst, R.B.M.; Donker, H.

    2000-01-01

    The phase behavior of three N-alkyl-substituted perylene diimide derivatives is examined by differential scanning calorimetry and polarized optical microscopy. The occurrence of multiple phase transitions indicates several crystalline and several liquid crystalline phases. X-ray diffraction

  13. Electromagnetic processes in strong crystalline fields

    CERN Multimedia

    2007-01-01

    We propose a number of new investigations on aspects of radiation from high energy electron and positron beams (10-300 GeV) in single crystals and amorphous targets. The common heading is radiation emission by electrons and positrons in strong electromagnetic fields, but as the setup is quite versatile, other related phenomena in radiation emission can be studied as well. The intent is to clarify the role of a number of important aspects of radiation in strong fields as e.g. observed in crystals. We propose to measure trident 'Klein-like' production in strong crystalline fields, 'crystalline undulator' radiation, 'sandwich' target phenomena, LPM suppression of pair production as well as axial and planar effects in contributions of spin to the radiation.

  14. Liquid Crystalline Semiconductors Materials, properties and applications

    CERN Document Server

    Kelly, Stephen; O'Neill, Mary

    2013-01-01

    This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...

  15. Application of thermodynamics to silicate crystalline solutions

    Science.gov (United States)

    Saxena, S. K.

    1972-01-01

    A review of thermodynamic relations is presented, describing Guggenheim's regular solution models, the simple mixture, the zeroth approximation, and the quasi-chemical model. The possibilities of retrieving useful thermodynamic quantities from phase equilibrium studies are discussed. Such quantities include the activity-composition relations and the free energy of mixing in crystalline solutions. Theory and results of the study of partitioning of elements in coexisting minerals are briefly reviewed. A thermodynamic study of the intercrystalline and intracrystalline ion exchange relations gives useful information on the thermodynamic behavior of the crystalline solutions involved. Such information is necessary for the solution of most petrogenic problems and for geothermometry. Thermodynamic quantities for tungstates (CaWO4-SrWO4) are calculated.

  16. Determination of chloride content in crystalline silicotitanate

    International Nuclear Information System (INIS)

    Wilmarth, W.R.

    1999-01-01

    Crystalline Silicotitanate (CST) is one of three options under evaluation to replace the In-Tank Precipitation process. This Salt Disposition Alternatives team identified three options for pretreatment of High Level Waste supernate: non-elutable ion exchange, precipitation with sodium tetraphenylborate or direct disposal in grout. The ion exchange option would use crystalline silicotitanate (CST). Researchers at Texas A and M and Sandia National Laboratory developed CST. The engineered form of CST was procured from UOP LLC under the trade name IONSIVreg s ign IE-911. Review of vendor literature and discussions with UOP personnel led to speculation concerning the fate of chloride ion during the manufacture process of IE-911. Walker proposed tests to examine the chloride content of CST and removal methods. This report describes the results of tests to determine the chloride levels in as received CST and washed CST

  17. Total scattering of disordered crystalline functional materials

    International Nuclear Information System (INIS)

    Shamoto, Shin-Ichi; Kodama, Katsuaki; Iikubo, Satoshi; Taguchi, Tomitsugu

    2009-01-01

    There are disorders in some modern functional materials. As an example, the crystalline phase of an optical recording material has low thermal conductivity but high electrical conductivity, simultaneously. This contradiction is a challenge to material scientists in designing good functional materials, which should have at least two types of crystallographic sites. One site limits thermal conductivity while the other site carries electrons or holes with high mobility. This problem exists with not only optical recording materials but also thermoelectric materials. The periodic boundary condition gets lost in the disordered parts. This therefore, makes atomic pair distribution function (PDF) analysis with a wide range of real space suitable for investigating the form and size of crystalline parts as well as disordered parts in the material. Pulsed neutron powder diffraction is one of the best tools for use in this new type of emerging research, together with synchrotron X-ray powder diffraction and electron diffraction.

  18. Plasmonic Physics of 2D Crystalline Materials

    Directory of Open Access Journals (Sweden)

    Zahra Torbatian

    2018-02-01

    Full Text Available Collective modes of doped two-dimensional crystalline materials, namely graphene, MoS 2 and phosphorene, both monolayer and bilayer structures, are explored using the density functional theory simulations together with the random phase approximation. The many-body dielectric functions of the materials are calculated using an ab initio based model involving material-realistic physical properties. Having calculated the electron energy-loss, we calculate the collective modes of each material considering the in-phase and out-of-phase modes for bilayer structures. Furthermore, owing to many band structures and intreband transitions, we also find high-energy excitations in the systems. We explain that the material-specific dielectric function considering the polarizability of the crystalline material such as MoS 2 are needed to obtain realistic plasmon dispersions. For each material studied here, we find different collective modes and describe their physical origins.

  19. Synthesis of biocompatible polymers by plasma

    International Nuclear Information System (INIS)

    Colin O, E.

    2007-01-01

    the smallest contact angles. It has been demonstrated that the high energy of plasma in the polymers favors certain crystalline arrangement due to the reorganization of polymeric chains. In this work the crystallinity was calculated by means of areas under the curve of the amorphous and crystalline signals obtained by X-ray diffraction. The crystallinity in PPy/PEG increases from 8% to 9.5%. In Poly allylamine (PAl) the crystallinity was from 4% to 16%. The crystallinity in these materials increases when the increases synthesis energy. While in PPy the crystallinity diminishes from 16% to 12% when the synthesis energy increases, due to the fragmentation and/or possible ramifications of the pyrrole rings that reduce the formation of orderly regions with the energy increments. This characteristic is important, because they can be ended up forming conduction channels in the polymer that is reflected in the electric conductivity of the material. The electric conductivity is another important factor in this study, since due to the electric impulses generated among materials and cells it can stimulates the cellular growth. The electric response of the polymers was study in function of the relative humidity in the interval of 25-80% and in function of the volume of the solutions of NaCl, NaCl-MgSO 4 , and Krebs-Ringer. In the interval of 25-80% of relative humidity, the increment in the electric conductivity in PPy/PEG went from 10 -12 to 10 -10 S/cm at 25% and of 10 -12 to 10 -8 S/cm to 80% of relative humidity. The electric conductivity regarding the humidity in PAl increases from 10 -11 of 10 -9 S/cm to 25% and of 10 - 1 0 to 10 -8 S/cm at 80%. In Poly pyrrole (PPy) and doped poly pyrrole with Iodine (PPy/I) one observes that the electric conductivity in the interval 25% to 80% of relative humidity went from 10 -9 to 10 11 S/cm in PPy and 10 -8 and 10 -10 S/cm in PPy/I almost increases two magnitude orders when increasing the relative humidity. The polymers showed a

  20. Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1999-01-01

    Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

  1. University Crystalline Silicon Photovoltaics Research and Development

    Energy Technology Data Exchange (ETDEWEB)

    Ajeet Rohatgi; Vijay Yelundur; Abasifreke Ebong; Dong Seop Kim

    2008-08-18

    The overall goal of the program is to advance the current state of crystalline silicon solar cell technology to make photovoltaics more competitive with conventional energy sources. This program emphasizes fundamental and applied research that results in low-cost, high-efficiency cells on commercial silicon substrates with strong involvement of the PV industry, and support a very strong photovoltaics education program in the US based on classroom education and hands-on training in the laboratory.

  2. Reactions and Interactions in Liquid Crystalline Media

    Science.gov (United States)

    1991-10-30

    nematic lyophases of potassium laurate, myristyl tri methylammonium bromide or sodium decylsulfate with 1-decanol and 23 water. A strong retardation of the...crystalline polyacrylate crosslinked elastomers were synthesized. 198c 0 0 96 0 0 0O-(CH12 ) 2 -0O(k 97 Crosslinking, up to 10% of structural units produced...in their isotropic state and they work as the transporting phase for the azo-crown ether molecules. The permeation of K+ from a potassium p

  3. The phase diagram of crystalline surfaces

    International Nuclear Information System (INIS)

    Anagnostopoulos, K.N.; Bowick, M.J.; Catterall, S.M.

    1995-01-01

    We report the status of a high-statistics Monte Carlo simulation of non-self-avoiding crystalline surfaces with extrinsic curvature on lattices of size up to 128 2 nodes. We impose free boundary conditions. The free energy is a gaussian spring tethering potential together with a normal-normal bending energy. Particular emphasis is given to the behavior of the model in the cold phase where we measure the decay of the normal-normal correlation function

  4. Colloid properties in groundwaters from crystalline formations

    International Nuclear Information System (INIS)

    Degueldre, C.A.

    1994-09-01

    Colloids are present in all groundwaters. The role they may play in the migration of safety-relevant radionuclides in the geosphere therefore must be studied. Colloid sampling and characterisation campaigns have been carried out in Switzerland. On the bases of the results from studies in the Grimsel area, Northern Switzerland and the Black Forest, as well as those obtained by other groups concerned with crystalline waters, a consistent picture is emerging. The groundwater colloids in crystalline formations are predominantly comprised of phyllosilicates and silica originating from the aquifer rock. Under constant hydrogeochemical conditions, the colloid concentration is not expected to exceed 100 ng.ml -1 when the calcium concentration is greater than 10 -4 . However, under transient chemical or physical conditions, such as geothermal or tectonic activity, colloid generation may be enhanced and the colloid concentration may reach 10 μg.ml -1 or more, if both the calcium and sodium concentrations are low. In the Nagra Crystalline Reference Water the expected colloid concentration is -1 . This can be compared, for example, to a colloid concentration of about 10 ng.ml -1 found in Zurzach water. The small colloid concentration in the reference water is a consequence of an attachment factor for clay colloids (monmorillonite) close to 1. A model indicates that at pH 8, the nuclide partition coefficients between water and colloid (K p ) must be smaller than 10 7 ml.g -1 if sorption takes place by surface complexation on colloids, = AIOH active groups forming the dominant sorption sites. This pragmatic model is based on the competition between the formation of nuclide hydroxo complexes in solution and their sorption on colloids. Experimental nuclide sorption data on colloids are compared with those obtained by applying this model. For a low colloid concentration, a sorption capacity of the order of 10 -9 M and reversible surface complexation, their presence in the

  5. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  6. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  7. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  8. Crystallinity in starch plastics: consequences for material properties

    NARCIS (Netherlands)

    Soest, van J.J.G.; Vliegenthart, J.F.G.

    1997-01-01

    The processing of starches with biodegradable additives has made biodegradable plastics suitable for a number of applications. Starch plastics are partially crystalline as a result of residual crystallinity and the recrystallization of amylose and amylopectin. Such crystallinity is a key determinant

  9. Crystalline lens power and refractive error.

    Science.gov (United States)

    Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

    2012-02-01

    To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

  10. Crystalline to amorphous transformation in silicon

    International Nuclear Information System (INIS)

    Cheruvu, S.M.

    1982-09-01

    In the present investigation, an attempt was made to understand the fundamental mechanism of crystalline-to-amorphous transformation in arsenic implanted silicon using high resolution electron microscopy. A comparison of the gradual disappearance of simulated lattice fringes with increasing Frenkel pair concentration with the experimental observation of sharp interfaces between crystalline and amorphous regions was carried out leading to the conclusion that when the defect concentration reaches a critical value, the crystal does relax to an amorphous state. Optical diffraction experiments using atomic models also supported this hypothesis. Both crystalline and amorphous zones were found to co-exist with sharp interfaces at the atomic level. Growth of the amorphous fraction depends on the temperature, dose rate and the mass of the implanted ion. Preliminary results of high energy electron irradiation experiments at 1.2 MeV also suggested that clustering of point defects occurs near room temperature. An observation in a high resolution image of a small amorphous zone centered at the core of a dislocation is presented as evidence that the nucleation of an amorphous phase is heterogeneous in nature involving clustering or segregation of point defects near existing defects

  11. The strength of crystalline color superconductors

    International Nuclear Information System (INIS)

    Mannarelli, Massimo; Rajagopal, Krishna; Sharma, Rishi

    2007-01-01

    We present a study of the shear modulus of the crystalline color superconducting phase of quark matter, showing that this phase of dense, but not asymptotically dense, quark matter responds to shear stress as a very rigid solid. This phase is characterized by a gap parameter Δ that is periodically modulated in space and therefore spontaneously breaks translational invariance. We derive the effective action for the phonon fields that describe space- and time-dependent fluctuations of the crystal structure formed by Δ, and obtain the shear modulus from the coefficients of the spatial derivative terms. Within a Ginzburg-Landau approximation, we find shear moduli which are 20 to 1000 times larger than those of neutron star crusts. This phase of matter is thus more rigid than any known material in the universe, but at the same time the crystalline color superconducting phase is also superfluid. These properties raise the possibility that the presence of this phase within neutron stars may have distinct implications for their phenomenology. For example (some) pulsar glitches may originate in crystalline superconducting neutron star cores

  12. Crystalline beams: Theory, experiments, and proposals

    International Nuclear Information System (INIS)

    Ruggiero, A.G.

    1995-01-01

    Crystalline Beams are an ordered state of an ensemble of ions, circulating in a storage ring, with very small velocity fluctuations. They can be obtained from ordinary warm ion beams with the application of intense cooling techniques (stochastic, electron, laser). A phase transition occurs when sufficiently small velocity spreads are reached, freezing the particle-to-particle spacing in strings, Zigzags, and helices ... The properties and the feasibility of Crystalline Beams depend on the choice of the lattice of the Storage Ring. There are three issues closely related to the design of the Storage Ring; namely: the determination of Equilibrium Configurations, Confinement Conditions, and Stability Conditions. Of particular concern is the effect of the trajectory curvature and of the beam momentum spread, since they set the requirements on the amount of momentum cooling, on the focussing, and on the distribution of bending in the lattice of the storage ring. The practical demonstration of Crystalline Beams may create the basis for an advanced technology for particle accelerators, where the limitations due to Coulomb intrabeam scattering and space-charge forces would finally be brought under control, so that beams of ions, more dense than normal, can be achieved for a variety of new applications

  13. Fluorination of polymers

    International Nuclear Information System (INIS)

    Du Toit, F.J.

    1991-01-01

    Polyethylene and polypropylene were reacted with elemental fluorine under carefully controlled conditions to produce fluorocarbon polymers. Fluorination of polymer films resulted in fluorination of only the outer surfaces of the films, while the reaction of elemental fluorine with powdered hydrocarbon polymers produced perfluorocarbon polymers. Existing and newly developed techniques were used to characterize the fluorinated polymers. It was shown that the degree of fluorination was influenced by the surface area of the hydrocarbon material, the concentration, of the fluorine gas, and the time and temperature of fluorination. A fluidized-bed reactor used for the fluorination of polymer powders effectively increased the reaction rate. The surface tension and the oxygen permeability of the fluorinated polymers were studied. The surface tension of hydrocarbon polymers was not influenced by different solvents, but the surface tension of fluorinated polymers was affected by the type of solvent that was used. There were indications that the surface tension was affected by oxygen introduced into the polymer surface during fluorination. Fluorination lowered the permeability of oxygen through hydrocarbon polymers. 55 refs., 51 figs., 26 tabs

  14. Advanced polymers in medicine

    CERN Document Server

    Puoci, Francesco

    2014-01-01

    The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

  15. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein...... is mediated through specific transporters, it is thought that the accumulation can be alleviated through the attachment of ribavirin to a macromolecule. To this end, ribavirin was enzymatically modified into a monomer compatible with controlled polymerization techniques. The ribavirin monomers were...

  16. Polymer reaction engineering, an integrated approach

    NARCIS (Netherlands)

    Meyer, T.; Keurentjes, J.T.F.; Meyer, T.; Keurentjes, J.T.F.

    2005-01-01

    Summary This chapter contains sections titled: Polymer Materials A Short History of Polymer Reaction Engineering The Position of Polymer Reaction Engineering Toward Integrated Polymer Reaction Engineering The Disciplines in Polymer Reaction Engineering The Future: Product-inspired Polymer Reaction

  17. Effects on the Thermo-Mechanical and Crystallinity Properties of Nylon 6,6 Electrospun Fibres Reinforced with One Dimensional (1D and Two Dimensional (2D Carbon

    Directory of Open Access Journals (Sweden)

    Francisco Medellín-Rodríguez

    2013-08-01

    Full Text Available Electrospun one dimensional (1D and two dimensional (2D carbon based polymer nanocomposites are studied in order to determine the effect provided by the two differently structured nanofillers on crystallinity and thermo-mechanical properties of the nanofibres. The nanomaterials studied are pristine carbon nanotubes, oxidised carbon nanotubes, reduced graphene oxide and graphene oxide. Functional groups associated with the order structure of the polymers are analysed by infrared and Raman spectroscopies; the morphology is studied by scanning electron microscopy and the crystallinity properties are investigated by differential scanning calorimetry and X-ray diffraction. Differences in crystallisation behaviour between 1D and 2D carbon based nanofibres are shown by their crystallinity degree and their crystal sizes. The nanocomposite crystal sizes perpendicular to the plane (100 decrease with nanofiller content in all cases. The crystallinity trend and crystal sizes are in accordance with storage modulus response. The results also suggest that functionalisation favours interfacial bonding and dispersion of the nanomaterials within the polymer matrix. As a consequence the number of nucleating sites increases which in turn decreases the crystal size in the nanocomposites. These features explain the improved thermo-mechanical properties in the nanocomposites.

  18. Electrical transport in crystalline phase change materials

    International Nuclear Information System (INIS)

    Woda, Michael

    2012-01-01

    In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge 2 Sb 2 Te 5 . The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

  19. Electrical transport in crystalline phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Woda, Michael

    2012-01-06

    In this thesis, the electrical transport properties of crystalline phase change materials are discussed. Phase change materials (PCM) are a special class of semiconducting and metallic thin film alloys, typically with a high amount of the group five element antimony or the group six element tellurium, such as Ge{sub 2}Sb{sub 2}Te{sub 5}. The unique property portfolio of this material class makes it suitable for memory applications. PCMs reveal fast switching between two stable room-temperature phases (amorphous and crystalline) realized by optical laser or electrical current pulses in memory devices. Additionally, a pronounced property contrast in form of optical reflectivity and electrical conductivity between the amorphous and crystalline phase is the characteristic fingerprint of PCMs. The emerging electrical solid state memory PCRAM is a very promising candidate to replace Flash memory in the near future or to even become a universal memory, which is non-volatile and shows the speed and cyclability of DRAM. One of the main technological challenges is the switching process into the amorphous state, which is the most power demanding step. In order to reduce the switching power, the crystalline resistivity needs to be increased at a given voltage. Thus understanding and tayloring of this property is mandatory. In this work, first the technological relevance, i.e. optical and electrical memory concepts based on PCMs are introduced. Subsequently a description of the physical properties of PCMs in four categories is given. Namely, structure, kinetics, optical properties and electrical properties are discussed. Then important recent developments such as the identification of resonant bonding in crystalline PCMs and a property predicting coordination scheme are briefly reviewed. The following chapter deals with the theoretical background of electrical transport, while the next chapter introduces the experimental techniques: Sputtering, XRR, XRD, DSC, thermal annealing

  20. Crystallinity and order of poly(ethylene oxide)/lithium triflate complex confined in nanoporous membranes

    International Nuclear Information System (INIS)

    Bishop, Christina; Teeters, Dale

    2009-01-01

    The confinement of poly(ethylene oxide), PEO, electrolyte in pores of 13, 35, 55 and 100 nm in diameter in nanoporous alumina membranes was seen to have effects on the ionic conduction properties. Specific conductivity values for the PEO/lithium triflate complex in the 13 and 35 nm pores, for temperatures below the melt temperatures, were increased by a factor of four compared to the non-confined polymer and the 55 and 100 nm pore systems. Thermal analysis data indicate the melting temperature for the PEO electrolyte in the pores is directly proportional to the pore size such that as the pore size of confinement is decreased, the T m decreases as well. The same behavior is seen for the amount of crystallinity, with less crystallinity being observed as the pores become smaller. Perhaps the observed conduction behavior could be attributed to less crystallinity. However, it is known that confinement of polyethers in pores results in stretching and ordering of the backbone and that such ordering can increase ion conduction. This ordering would seem to be the major factor involved in these results. The enhanced conduction only being seen in the 13 and 35 nm pores and not the 55 and 100 nm pores is attributed to the larger size for the latter which allows a more bulk-like behavior with less ordering.

  1. Influence of Chemical Treatments Sequence on Morphology and Crystallinity of Sorghum Fibers

    Directory of Open Access Journals (Sweden)

    Ismojo Ismojo

    2018-05-01

    Full Text Available Micro-fibrillated cellulose (MFC derived from natural fibre is continuously gaining interest to produce an environmentally-friendly material, due to economic and ecological reasons. In consequence, sorghum is one of the most-cultivated crops that usually remain the waste as by product of bioethanol production. Indeed, it will be a promising area to utilize sorghum waste to produce MFC for enhancing polymer performance, especially in terms of crystallinity. The objective of this study is to investigate the effect of a sequence of chemical modification was applied to sorghum fibres, i.e. alkalization using 4% sodium hydroxide followed by bleaching using 1.7% sodium chlorite plus acetic acid as a buffer. The treatment was purposed to unbundle the lignocellulose networks into microfibrils cellulose with less amorphous part and lower hydrophilic properties. Evaluation of the chemical treatments effect on internal microstructure, crystallinity index and chemical composition of sorghum fibre was measured via Field-Emission Scanning Electron microscope (FE-SEM, X-ray Diffraction (XRD and Fourier Transformation Infra-Red (FTIR Spectroscopy. The experiments show that treatments led to a removal of binding materials, such as amorphous parts hemicellulose and lignin, from the sorghum fibres, resulting MFC of sorghum fibres and enhanced crystallinity index from 41.12 % to 75.73%.

  2. Electrically Reconfigurable Liquid Crystalline Mirrors (Postprint)

    Science.gov (United States)

    2018-04-24

    focus on dynamic reconfiguration of the reflection band gap of polymer-stabilized cholesteric liquid crystals (PSCLCs). Recent research has reported the...public release: distribution unlimited. © 2018 AMERICAN CHEMICAL SOCIETY (STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING...MONITORING AGENCY ACRONYM(S) Air Force Research Laboratory Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH

  3. TCT-584 Nine Month Imaging and Twelve Month Clinical Results from the DESSOLVE II Randomized Trial of the MiStent® SES with Absorbable Polymer

    OpenAIRE

    Wijns, William; Vrolix, Mathias; Verheye, Stefan; Schoors, Danny; Slagboom, Ton; Gosselink, Marcel; Benit, Edouard; Desmet, Walter; Chowdhary, Saquib; Lansky, Alexandra; Bezerra, Hiram; Fitzgerald, Peter; Kandzari, David; Ormiston, John

    2012-01-01

    Background : The MiStent SES (Micell Technologies, Durham, NC) is an investigational drug-eluting stent (DES) developed to adress unfavorable late-term outcomes such as stent thrombosis. These events are hypothesized to be associated in part with durable polymers of current DES. The MiStent SES uses a unique combination of components, a crystalline formulation of sirolimus and a fully absorbable polymer on a thinstrut, cobalt chromium stent platform. The polymer coating is eliminated from the...

  4. Impact of the Formulation Pathway on the Colloidal State and Crystallinity of Poly-ε-caprolactone Particles Prepared by Solvent Displacement.

    Science.gov (United States)

    Pucci, Carlotta; Cousin, Fabrice; Dole, François; Chapel, Jean-Paul; Schatz, Christophe

    2018-02-20

    The formulation pathway and/or the mixing method are known to be relevant in many out-of-equilibrium processes. In this work, we studied the effect of the mixing conditions on the physicochemical properties of poly-ε-caprolactone (PCL) particles prepared by solvent displacement. More specifically, water was added in one shot (fast addition) or drop by drop to PCL solution in tetrahydrofuran (THF) to study the impact of the mixing process on particle properties including size, stability, and crystallinity. Two distinct composition maps representing the Ouzo domain characteristic of the presence of metastable nanoparticles have been established for each mixing method. Polymer nanoparticles are formed in the Ouzo domain according to a nucleation and growth (or aggregation) mechanism. The fast addition promotes a larger nucleation rate, thus favoring the formation of small and uniform particles. For the drop-by-drop addition, for which the polymer solubility gradually decreases, the composition trajectories systematically cross an intermediate unstable region between the solubility limit of the polymer and the Ouzo domain. This leads to heterogeneous nucleation as shown by the formation of larger and less stable particles. Particles formed in the Ouzo domain have semi-crystalline properties. The PCL melting point is decreased with the THF fraction trapped in particles in accordance with Flory's theory for melt crystallization. On the other hand, the degree of crystallinity is constant, around 20% regardless of the THF fraction. No difference between fast and slow addition could be detected on the semi-crystalline properties of the particles which emphasize that thermodynamic rather than kinetic factors drive the polymer crystallization in particles. The recovery of bulk PCL crystallinity after the removal of THF from particles tends to confirm this hypothesis.

  5. Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends

    Directory of Open Access Journals (Sweden)

    Ilze ELKSNITE

    2011-07-01

    Full Text Available Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-polyester modifier on the properties of polyethylene is investigated. Various compositions of laboratory synthesized hydroxybenzoic acid /polyethylene terephtalate copolymer containing polyethylene composites have been manufactured by thermoplastic blending. It has been observed that 1 modulus of elasticity, yield strength and ultimate strength increase with raising the content of liquid crystalline modifier; 2 void content in the investigated polyethylene/liquid crystal copolymer composites is not greater that 1 %; 3 addition of liquid crystalline co-polyester modifier improves arrangement of PE crystalline phase.http://dx.doi.org/10.5755/j01.ms.17.2.483

  6. Influence of structures of polymer backbones on cooperative photoreorientation behavior of p-cyanoazobenzene side chains

    DEFF Research Database (Denmark)

    Han, Mina; Kidowaki, Masatoshi; Ichimura, Kunihiro

    2001-01-01

    Photoinduced orientational behavior of a polymethacrylate (CN6) and a polyester (p6a12) with p-cyanoazobenzene side chains was studied to reveal the structural effect of the liquid crystalline polymer backbones. Irradiation with linearly polarized W light resulted in the reorientation of the azob...

  7. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira; Hayashi, Mayumi; Ito, Shotaro; Goseki, Raita; Higashihara, Tomoya; Hadjichristidis, Nikolaos

    2015-01-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic

  8. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    Abstract. Starting from the standard model of polymer motion – the Rouse model – .... reptation and the escape processes (creep motion) from the tube. .... scattering curves from an arrangement of small mesoscopic spheres also allows a.

  9. Indolo-naphthyridine-6,13-dione Thiophene Building Block for Conjugated Polymer Electronics: Molecular Origin of Ultrahigh n-Type Mobility

    KAUST Repository

    Fallon, Kealan J.

    2016-10-18

    Herein, we present the synthesis and characterization of four conjugated polymers containing a novel chromophore for organic electronics based on an indigoid structure. These polymers exhibit extremely small band gaps of ∼1.2 eV, impressive crystallinity, and extremely high n-type mobility exceeding 3 cm V s. The n-type charge carrier mobility can be correlated with the remarkably high crystallinity along the polymer backbone having a correlation length in excess of 20 nm. Theoretical analysis reveals that the novel polymers have highly rigid nonplanar geometries demonstrating that backbone planarity is not a prerequisite for either narrow band gap materials or ultrahigh mobilities. Furthermore, the variation in backbone crystallinity is dependent on the choice of comonomer. OPV device efficiencies up to 4.1% and charge photogeneration up to 1000 nm are demonstrated, highlighting the potential of this novel chromophore class in high-performance organic electronics.

  10. Indolo-naphthyridine-6,13-dione Thiophene Building Block for Conjugated Polymer Electronics: Molecular Origin of Ultrahigh n-Type Mobility

    KAUST Repository

    Fallon, Kealan J.; Wijeyasinghe, Nilushi; Manley, Eric F.; Dimitrov, Stoichko D.; Yousaf, Syeda A.; Ashraf, Raja S.; Duffy, Warren; Guilbert, Anne A. Y.; Freeman, David M. E.; Al-Hashimi, Mohammed; Nelson, Jenny; Durrant, James R.; Chen, Lin X.; McCulloch, Iain; Marks, Tobin J.; Clarke, Tracey M.; Anthopoulos, Thomas D.; Bronstein, Hugo

    2016-01-01

    Herein, we present the synthesis and characterization of four conjugated polymers containing a novel chromophore for organic electronics based on an indigoid structure. These polymers exhibit extremely small band gaps of ∼1.2 eV, impressive crystallinity, and extremely high n-type mobility exceeding 3 cm V s. The n-type charge carrier mobility can be correlated with the remarkably high crystallinity along the polymer backbone having a correlation length in excess of 20 nm. Theoretical analysis reveals that the novel polymers have highly rigid nonplanar geometries demonstrating that backbone planarity is not a prerequisite for either narrow band gap materials or ultrahigh mobilities. Furthermore, the variation in backbone crystallinity is dependent on the choice of comonomer. OPV device efficiencies up to 4.1% and charge photogeneration up to 1000 nm are demonstrated, highlighting the potential of this novel chromophore class in high-performance organic electronics.

  11. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  12. Polymerization and processing of organic polymers in a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, E.P. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The use of magnetic fields to affect the structure and properties of polymeric materials remains an area of great promise. Liquid crystalline polymers have been actively studied over the past 20 years for use in high performance structural applications. In particular, highly oriented fibers can exhibit remarkable increases in strength to weight performance compared to conventional materials. For example, the fibers marketed by DuPont under the tradename Kevlar are 20 times stronger than steel on an equivalent weight basis. However, larger bulk parts do not exhibit the same increases in strength due to a lack of orientation of the polymer molecules. Magnetic field processing of polymers remains an attractive solution to this problem.

  13. Crystal structure and thin film morphology of BBL ladder polymer

    Energy Technology Data Exchange (ETDEWEB)

    Song, H H [Department of Macromolecular Science, Han Nam University, Taejon (Korea, Republic of); Fratini, A V [Department of Chemistry, University of Dayton, Dayton, OH (United States); Chabinyc, M [Department of Chemistry, University of Dayton, Dayton, OH (United States); Price, G E [University of Dayton Research, Dayton, OH (United States); Agrawal, A K [Systran Corporation, Dayton, OH (United States); Wang, C S [University of Dayton Research, Dayton, OH (United States); Burkette, J [University of Dayton Research, Dayton, OH (United States); Dudis, D S [Materials Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH (United States); Arnold, F E [Materials Directorate, Wright Laboratory, Wright-Patterson Air Force Base, OH (United States)

    1995-03-01

    Crystal structure and morphology of poly[7-oxo-7H-benz(d,e)imidazo(4`,5`:5,6)-benzimidazo(2,1-a)isoquinoline-3,4:10,11-tetrayl-10-carbonyl] (BBL) ladder-like polymer were studied. The polymer forms a two-dimensional lattice of nematic liquid crystalline structure. An orthorhombic unit cell with cell parameters of a=7.87 b=3.37 c=11.97A was determined from the fiber diffraction pattern. In thin films, the rigid chains spontaneously form a layered structure across the film thickness, but in a very unusual manner, i.e. the very large molecular plane is standing perpendicularly to the film surface plane. The results are identical to our recent results of poly(p-phenylene benzobisthiazole) (PBT) film [7]. The polymer, however, lost its anisotropic order upon extrusion into a film and resulted in a fiber-like structure. (orig.)

  14. Electrospun PVdF-based fibrous polymer electrolytes for lithium ion polymer batteries

    International Nuclear Information System (INIS)

    Kim, Jeong Rae; Choi, Sung Won; Jo, Seong Mu; Lee, Wha Seop; Kim, Byung Chul

    2004-01-01

    This paper discusses the preparation of microporous fibrous membranes from PVdF solutions with different polymer contents, using the electrospinning technique. Electrospun PVdF-based fibrous membranes with average fiber diameters (AFD's) of 0.45-1.38 μm have an apparent porosity and a mean pore size (MPS) of 80-89% and 1.1-4.3 μm, respectively. They exhibited a high uptake of the electrolyte solution (320-350%) and a high ionic conductivity of above 1 x 10 -3 s/cm at room temperature. Their ionic conductivity increased with the decrease in the AFD of the fibrous membrane due to its high electrolyte uptake. The interaction between the electrolyte molecules and the PVdF with a high crystalline content may have had a minor effect on the lithium ion transfer in the fibrous polymer electrolyte, unlike in a nanoporous gel polymer electrolyte. The fibrous polymer electrolyte that contained a 1 M LiPF 6 -EC/DMC/DEC (1/1/1 by weight) solution showed a high electrochemical stability of above 5.0 V, which increased with the decrease in the AFD The interfacial resistance (R i ) between the polymer electrolyte and the lithium electrode slightly increased with the storage time, compared with the higher increase in the interfacial resistance of other gel polymer electrolytes. The prototype cell (MCMB/PVdF-based fibrous electrolyte/LiCoO 2 ) showed a very stable charge-discharge behavior with a slight capacity loss under constant current and voltage conditions at the C/2-rate of 20 and 60 deg. C

  15. Biomimetic processing of oriented crystalline ceramic layers

    Energy Technology Data Exchange (ETDEWEB)

    Cesarano, J.; Shelnutt, J.A.

    1997-10-01

    The aim of this project was to develop the capabilities for Sandia to fabricate self assembled Langmuir-Blodgett (LB) films of various materials and to exploit their two-dimensional crystalline structure to promote the growth of oriented thin films of inorganic materials at room temperature. This includes the design and synthesis of Langmuir-active (amphiphilic) organic molecules with end groups offering high nucleation potential for various ceramics. A longer range goal is that of understanding the underlying principles, making it feasible to use the techniques presented in this report to fabricate unique oriented films of various materials for electronic, sensor, and membrane applications. Therefore, whenever possible, work completed in this report was completed with the intention of addressing the fundamental phenomena underlying the growth of crystalline, inorganic films on template layers of highly organized organic molecules. This problem was inspired by biological processes, which often produce exquisitely engineered structures via templated growth on polymeric layers. Seashells, for example, exhibit great toughness owing to their fine brick-and-mortar structure that results from templated growth of calcium carbonate on top of layers of ordered organic proteins. A key goal in this work, therefore, is to demonstrate a positive correlation between the order and orientation of the template layer and that of the crystalline ceramic material grown upon it. The work completed was comprised of several parallel efforts that encompassed the entire spectrum of biomimetic growth from solution. Studies were completed on seashells and the mechanisms of growth for calcium carbonate. Studies were completed on the characterization of LB films and the capability developed for the in-house fabrication of these films. Standard films of fatty acids were studied as well as novel polypeptides and porphyrins that were synthesized.

  16. Artificially Engineered Protein Polymers.

    Science.gov (United States)

    Yang, Yun Jung; Holmberg, Angela L; Olsen, Bradley D

    2017-06-07

    Modern polymer science increasingly requires precise control over macromolecular structure and properties for engineering advanced materials and biomedical systems. The application of biological processes to design and synthesize artificial protein polymers offers a means for furthering macromolecular tunability, enabling polymers with dispersities of ∼1.0 and monomer-level sequence control. Taking inspiration from materials evolved in nature, scientists have created modular building blocks with simplified monomer sequences that replicate the function of natural systems. The corresponding protein engineering toolbox has enabled the systematic development of complex functional polymeric materials across areas as diverse as adhesives, responsive polymers, and medical materials. This review discusses the natural proteins that have inspired the development of key building blocks for protein polymer engineering and the function of these elements in material design. The prospects and progress for scalable commercialization of protein polymers are reviewed, discussing both technology needs and opportunities.

  17. He implantation induced nanovoids in crystalline Si

    International Nuclear Information System (INIS)

    Kilpelaeinen, S.; Kuitunen, K.; Slotte, J.; Tuomisto, F.; Bruno, E.; Mirabella, S.; Priolo, F.

    2009-01-01

    Positron annihilation spectroscopy (PAS) in Doppler broadening mode was used to study the vacancy profile of crystalline Si after He and B implantation and subsequent annealing. In the He-implanted samples two different void layers were observed, one consisting of large voids at the projected range of He and another containing 'nanovoids' slightly larger than divacancies at roughly halfway between R p of He and the surface. The nanovoid layer was shown to be absent from samples co-implanted with B, implying that interstitials created during B implantation get trapped in the nanovoids and fill them, thus hindering interstitial-mediated B diffusion.

  18. Superacid Passivation of Crystalline Silicon Surfaces.

    Science.gov (United States)

    Bullock, James; Kiriya, Daisuke; Grant, Nicholas; Azcatl, Angelica; Hettick, Mark; Kho, Teng; Phang, Pheng; Sio, Hang C; Yan, Di; Macdonald, Daniel; Quevedo-Lopez, Manuel A; Wallace, Robert M; Cuevas, Andres; Javey, Ali

    2016-09-14

    The reduction of parasitic recombination processes commonly occurring within the silicon crystal and at its surfaces is of primary importance in crystalline silicon devices, particularly in photovoltaics. Here we explore a simple, room temperature treatment, involving a nonaqueous solution of the superacid bis(trifluoromethane)sulfonimide, to temporarily deactivate recombination centers at the surface. We show that this treatment leads to a significant enhancement in optoelectronic properties of the silicon wafer, attaining a level of surface passivation in line with state-of-the-art dielectric passivation films. Finally, we demonstrate its advantage as a bulk lifetime and process cleanliness monitor, establishing its compatibility with large area photoluminescence imaging in the process.

  19. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Wester, Ture; Weinzieri, Barbara

    The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells with fivefold symmetry in 3D space....... The quasi-crystal geometry can be constructed from two different cubic cells with identical rhombic facets, where the relation between the diagonals is the golden section. All cells have identical rhombic faces, identical edges and identical icosahedral/dodecahedral nodes....

  20. Singlet exciton interactions in crystalline naphthalene

    International Nuclear Information System (INIS)

    Heisel, F.; Miehe, J.A.; Sipp, B.

    1978-01-01

    The decay of prompt fluorescence in crystalline naphthalene at 300 K, excited by picosecond 266 nm pulse, has been studied as a function of excitation intensity. Experimental decay curves can be fitted only when the exponential distribution in depth of excitation and the radial (gaussian) intensity profile of the excitation are both taken into account. From analysis of decay at early time ( -10 cm 3 s -1 . If the reaction is diffusion-limited, this rate implies an average singlet diffusivity Dsub(S)=(2+-1)10 -4 cm 2 s -1

  1. New thermophilic anaerobes that decompose crystalline cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Taya, M; Hinoki, H; Suzuki, Y; Yagi, T; Yap, M G.S.; Kobayashi, T

    1985-01-01

    Two strains (designated as 25A and 3B) of cellulolytic, thermophilic, anaerobic, spore-forming bacteria were newly isolated from an alkaline hot spring through enrichment cultures at 60/sup 0/C. Though strain 25A was nearly identical to Clostridium thermocellum ATCC 27405 as a reference strain, strain 3B had some characteristics different from the reference; no flagellation, alkalophilic growth property (optimum pH of 7.5-8) and orange-colored pigmentation of the cell mass. Strain 3B effectively decomposed micro-crystalline cellulose (Avicel) and raw cellulosics (rice straw, newspaper, and bagasse) without physical or chemical pretreatments. 20 references, 2 figures, 2 tables.

  2. Synthesis and Characterization of Liquid Crystalline Epoxy Resins

    Science.gov (United States)

    2014-01-01

    greatly enhancing the matrix properties [1, 2]. In recent years, fiber reinforced polymer matrix composites (FRPs) have become one of the most important...Demand for Durable Polymer Matrix Composites: The National Academies Press, 2005. [9] Chung DDL. Carbon Fiber Composites: Butterworth- Heinemann , 1994...A-Polymer Chemistry 1993;31(9):2249-2260. [23] Jahromi S, Lub J, and Mol GN. Polymer 1994;35(3):622-629. [24] Hikmet RAM and Broer DJ. Polymer

  3. EFFECTS OF ULTRASOUND ON THE MORPHOLOGY, PARTICLE SIZE, CRYSTALLINITY, AND CRYSTALLITE SIZE OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    SUMARI SUMARI

    2014-05-01

    Full Text Available The aim of this study is to optimize ultrasound treatment to produce fragment of cellulose that is low in particles size, crystallite size, and crystallinity. Slurry of 1 % (w/v the cellulose was sonicated at different time periods and temperatures. An ultrasonic reactor was operated at 300 Watts and 28 kHz to cut down the polymer into smaller particles. We proved that ultrasound damages and fragments the cellulose particles into shorter fibers. The fiber lengths were reduced from in the range of 80-120 µm to 30-50 µm due to an hour ultrasonication and became 20-30 µm after 5 hours. It was also found some signs of erosion on the surface and stringy. The acoustic cavitation also generated a decrease in particle size, crystallinity, and crystallite size of the cellulose along with increasing sonication time but it did not change d-spacing. However, the highest reduction of particle size, crystallite size, and crystallinity of the cellulose occurred within the first hour of ultrasonication, after which the efficiency was decreased. The particle diameter, crystallite size, and crystallinity were decreased from 19.88 µm to 15.96 µm, 5.81 Å to 2.98 Å, and 77.7% to 73.9% respectively due to an hour ultrasound treatment at 40 °C. The treatment that was conducted at 40 °C or 60 °C did not give a different effect significantly. Cellulose with a smaller particle and crystallite size as well as a more amorphous shape is preferred for further study.

  4. Importance of crystallinity of anchoring block of semi-solid amphiphilic triblock copolymers in stabilization of silicone nanoemulsions.

    Science.gov (United States)

    Le Kim, Trang Huyen; Jun, Hwiseok; Nam, Yoon Sung

    2017-10-01

    Polymer emulsifiers solidified at the interface between oil and water can provide exceptional dispersion stability to emulsions due to the formation of unique semi-solid interphase. Our recent works showed that the structural stability of paraffin-in-water emulsions highly depends on the oil wettability of hydrophobic block of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-b-PCL). Here we investigate the effects of the crystallinity of hydrophobic block of triblock copolymer-based emulsifiers, PCLL-b-PEG-b-PCLL, on the colloidal properties of silicone oil-in-water nanoemulsions. The increased ratio of l-lactide to ε-caprolactone decreases the crystallinity of the hydrophobic block, which in turn reduces the droplet size of silicone oil nanoemulsions due to the increased chain mobility at the interface. All of the prepared nanoemulsions are very stable for a month at 37°C. However, the exposure to repeated freeze-thaw cycles quickly destabilizes the nanoemulsions prepared using the polymer with the reduced crystallinity. This work demonstrates that the anchoring chain crystallization in the semi-solid interphase is critically important for the structural robustness of nanoemulsions under harsh physical stresses. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Internally plasticised cellulose polymers

    International Nuclear Information System (INIS)

    Burnup, M.; Hayes, G.F.; Fydelor, P.J.

    1981-01-01

    Plasticised cellulose polymers comprise base polymer having a chain of β-anhydroglucose units joined by ether linkages, with at least one of said units carrying at least one chemically unreactive side chain derived from an allylic monomer or a vinyl substituted derivative of ferrocene. The side chains are normally formed by radiation grafting. These internally plasticised celluloses are useful in particular as inhibitor coatings for rocket motor propellants and in general wherever cellulose polymers are employed. (author)

  6. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  7. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alan M. [School of Applied Sciences, University of Huddersfield, Huddersfield HD1 3DH (United Kingdom); Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L. [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom); Grover, Liam M., E-mail: l.m.grover@bham.ac.uk [School of Chemical Engineering, University of Birmingham, Edgbaston, B15 2TT (United Kingdom)

    2015-03-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity.

  8. Nanoscale crystallinity modulates cell proliferation on plasma sprayed surfaces

    International Nuclear Information System (INIS)

    Smith, Alan M.; Paxton, Jennifer Z.; Hung, Yi-Pei; Hadley, Martin J.; Bowen, James; Williams, Richard L.; Grover, Liam M.

    2015-01-01

    Calcium phosphate coatings have been applied to the surface of metallic prostheses to mediate hard and soft tissue attachment for more than 40 years. Most coatings are formed of high purity hydroxyapatite, and coating methods are often designed to produce highly crystalline surfaces. It is likely however, that coatings of lower crystallinity can facilitate more rapid tissue attachment since the surface will exhibit a higher specific surface area and will be considerably more reactive than a comparable highly crystalline surface. Here we test this hypothesis by growing a population of MC3T3 osteoblast-like cells on the surface of two types of hip prosthesis with similar composition, but with differing crystallinity. The surfaces with lower crystallinity facilitated more rapid cell attachment and increased proliferation rate, despite having a less heterogeneous surface topography. This work highlights that the influence of the crystallinity of HA at the nano-scale is dominant over macro-scale topography for cell adhesion and growth. Furthermore, crystallinity could be easily adjusted by without compromising coating purity. These findings could facilitate designing novel coated calcium phosphate surfaces that more rapidly bond tissue following implantation. - Highlights: • Crystallinity of HA at the nano-scale was dominant over macro-scale topography. • Lower crystallinity caused rapid cell attachment and proliferation rate. • Crystallinity could be easily adjusted by without compromising coating purity

  9. Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers.

    Science.gov (United States)

    Vohra, Varun; Mróz, Wojciech; Inaba, Shusei; Porzio, William; Giovanella, Umberto; Galeotti, Francesco

    2017-08-02

    Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm 2 ), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials.

  10. Rheological analysis of irradiated crosslinkable and scissionable polymers used for medical devices under different radiation conditions

    Science.gov (United States)

    Satti, A. J.; Ressia, J. A.; Cerrada, M. L.; Andreucetti, N. A.; Vallés, E. M.

    2018-03-01

    The effects on different synthetic polymers of distinct types of radiation, gamma rays and electron beam, under different atmospheres are followed by changes in their viscoelastic behavior. Taking into account the two main radioinduced reactions, crosslinking and scissioning of polymeric chains, liquid polydimethylsiloxane has been used as example of crosslinkable polymer and semi crystalline polypropylene as example of scissionable polymer. Propylene - 1-hexene copolymers have been also evaluated, and the effects of both reactions were clearly noticed. Accordingly, samples of those aforementioned polymers have been irradiated with 60Co gamma irradiation in air and under vacuum, and also with electron beam, at similar doses. Sinusoidal dynamic oscillation experiments showed a significant increase in branching and crosslinking reactions when specimens are irradiated under vacuum, while scissioning reactions were observed for the different polymers when irradiation takes place under air with either gamma irradiation or electron beam.

  11. Vinyl Flanked Difluorobenzothiadiazole-Dithiophene Conjugated Polymer for High Performance Organic Field-Effect Transistors.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianfeng; Sun, Wandong; Chen, Yanlin; Tan, Luxi; Cai, Zheng-Xu; Liu, Zitong; Wang, Lin; Li, Jing; Chen, Wei; Dong, Lichun

    2018-02-21

    Fluorine containing conjugated polymers have been widely applied in high performance organic solar cells, but their use in field-effect transistors is still quite limited. In this work, a conjugated polymer PTFBTV based on difluorobenzothiadiazole (DFBT) and dithiophene was synthesized, utilizing multiple vinylene as linkers. The polymer exhibits a relatively high hole mobility up to 2.0 cm(2) V-1 s(-1) compared with the reported DFBT-oligothiophene based polymers, yet its structural complexity is much simpler. The polymer thin film exhibits a typical 'face on' molecular orientation. A single crystal of its monomer revealed a non-covalent intramolecular contact between fluorine and the neighbouring proton, which strengthens the backbone co-planarity. Meanwhile an intermolecular F...F contact was also observed, which might cause rather scattered lamellar crystallinity for PTFBTV in the solid state.

  12. The effects of bacteria on crystalline rock

    International Nuclear Information System (INIS)

    Brown, D.A.

    1994-01-01

    Many reactions involving inorganic minerals at water-rock interfaces have now been recognized to be bacterially mediated; these reactions could have a significant effect in the excavation of vaults for toxic and radioactive waste disposal. To investigate the role that bacteria play in the natural aqueous environment of crystalline rock the microbial growth factors of nutrition, energy and environment are described. Microbial activity has been investigated in Atomic Energy of Canada's Underground Research Laboratory (URL), situated in the Archean granitic Lac du Bonnet Batholith, Winnipeg, Manitoba. Faults, initiated in the Early Proterozoic, and later-formed fractures, provide ground-water pathways. Planktonic bacteria, free-swimming in the groundwater, have been observed in over 100 underground borehole samples. The number of bacteria varied from 10 3 to 10 5 mL -1 and appeared to decrease with depth and with increased salinity of the water. However, in the natural environment of deep (100-500 m) crystalline rocks, where nutrition is limited, formation of biofilms by sessile bacteria is a successful survival strategy. Natural biofilms at the URL and biofilms grown in bioreactors have been studied. The biofilms can accumulate different elements, depending upon the local environment. Precipitates of iron have been found in all the biofilms studied, where they are either passively accumulated or utilized as an energy source. Within the biofilm active and extensive biogeochemical immobilization of dissolved elements is controlled by distinct bacterial activities which are sufficiently discrete for hematite and siderite to be precipitated in close proximity

  13. Optical properties of crystalline semiconductors and dielectrics

    International Nuclear Information System (INIS)

    Forouhi, A.R.; Bloomer, I.

    1988-01-01

    A new formulation for the complex index of refraction, N(E) = n(E)-ik(E), as a function of photon energy E, for crystalline semiconductors and dielectrics is developed based on our previous derivation of N(E) for amorphous materials. The extinction coefficient k(E) is deduced from a one-electron model with finite lifetime for the excited electron state. The refractive index n(E) is then derived from the Kramers-Kronig relation as the Hilbert transform of k(E). It is shown that n(∞)>1. Excellent agreement is found between our equations for n(E) and k(E) and published measured values for crystalline Si, Ge, GaP, GaAs, GaSb, InP, InAs, InSb, SiC, cubic C, and α-SiO 2 , over a wide range of energies (∼0--20 eV). Far fewer parameters, all of which have physical significance, are required and they can be determined for a particular material from the position and strength of the peaks in the k spectrum

  14. Active colloidal propulsion over a crystalline surface

    Science.gov (United States)

    Choudhury, Udit; Straube, Arthur V.; Fischer, Peer; Gibbs, John G.; Höfling, Felix

    2017-12-01

    We study both experimentally and theoretically the dynamics of chemically self-propelled Janus colloids moving atop a two-dimensional crystalline surface. The surface is a hexagonally close-packed monolayer of colloidal particles of the same size as the mobile one. The dynamics of the self-propelled colloid reflects the competition between hindered diffusion due to the periodic surface and enhanced diffusion due to active motion. Which contribution dominates depends on the propulsion strength, which can be systematically tuned by changing the concentration of a chemical fuel. The mean-square displacements (MSDs) obtained from the experiment exhibit enhanced diffusion at long lag times. Our experimental data are consistent with a Langevin model for the effectively two-dimensional translational motion of an active Brownian particle in a periodic potential, combining the confining effects of gravity and the crystalline surface with the free rotational diffusion of the colloid. Approximate analytical predictions are made for the MSD describing the crossover from free Brownian motion at short times to active diffusion at long times. The results are in semi-quantitative agreement with numerical results of a refined Langevin model that treats translational and rotational degrees of freedom on the same footing.

  15. Molecular reorientations in a substance with liquid-crystalline and plastic-crystalline phases

    International Nuclear Information System (INIS)

    Nguyen, Xuan Phuc.

    1986-05-01

    Results of dielectric relaxation (DR), quasielastic neutron scattering (QNS), far infrared absorption (FIR), proton magnetic resonance (PMR), differential scanning calorimetry (DSC) and preliminary X-ray diffraction measurements on the di-n-pentyloxyazoxybenzene (5.OAOB) are presented. The measurements carried out by all these methods showed that 5.OAOB exhibits a nontypical for liquid-crystalline materials phase diagram. It has two mesophases: a nematic (N) and an ''intermediate'' crystalline phase just below it. A complex interpretation of results obtained is given. All suggestions concerning the character of reorientational motions of the molecule as a whole as well as of its segments in mesomorphic phases are analyzed. From comparison of the DR and QNS studies one can conclude that in the N phase the molecule as a whole performs rotational diffusion around the long axis (τ DR ∼ 100 ps) and at the same time the two moieties perform faster independent reorientations around N - benzene rings bonds withτ QNS ∼ 5 ps. On the basis of various experimental data it is shown that the CrI phase is a plastic-crystalline phase for which the molecule and its segments perform fast stochastic unaxial reorientations. This is the first case where the existence of such a phase in liquid-crystalline materials has been experimentally confirmed. (author)

  16. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  17. Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride)/acrylic rubber/clay nanocomposite hybrid.

    Science.gov (United States)

    Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

    2014-01-01

    In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules.

  18. Influence of miscibility phenomenon on crystalline polymorph transition in poly(vinylidene fluoride/acrylic rubber/clay nanocomposite hybrid.

    Directory of Open Access Journals (Sweden)

    Mohammad Mahdi Abolhasani

    Full Text Available In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride (PVDF and acrylic rubber(ACM was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules.

  19. Influence of Miscibility Phenomenon on Crystalline Polymorph Transition in Poly(Vinylidene Fluoride)/Acrylic Rubber/Clay Nanocomposite Hybrid

    Science.gov (United States)

    Abolhasani, Mohammad Mahdi; Naebe, Minoo; Jalali-Arani, Azam; Guo, Qipeng

    2014-01-01

    In this paper, intercalation of nanoclay in the miscible polymer blend of poly(vinylidene fluoride) (PVDF) and acrylic rubber(ACM) was studied. X-ray diffraction was used to investigate the formation of nanoscale polymer blend/clay hybrid. Infrared spectroscopy and X-ray analysis revealed the coexistence of β and γ crystalline forms in PVDF/Clay nanocomposite while α crystalline form was found to be dominant in PVDF/ACM/Clay miscible hybrids. Flory-Huggins interaction parameter (B) was used to further explain the miscibility phenomenon observed. The B parameter was determined by combining the melting point depression and the binary interaction model. The estimated B values for the ternary PVDF/ACM/Clay and PVDF/ACM pairs were all negative, showing both proper intercalation of the polymer melt into the nanoclay galleries and the good miscibility of PVDF and ACM blend. The B value for the PVDF/ACM blend was almost the same as that measured for the PVDF/ACM/Clay hybrid, suggesting that PVDF chains in nanocomposite hybrids interact with ACM chains and that nanoclay in hybrid systems is wrapped by ACM molecules. PMID:24551141

  20. Polymer gels and networks

    National Research Council Canada - National Science Library

    Osada, Yoshihito; Khokhlov, A. R

    2002-01-01

    ... or magnetic field, etc.). It was realized that not only can polymer gels absorb and hold a considerable volume of liquids, but they can also be forced to expel the absorbed liquid in a controlled manner. Of particular interest are hydrogels, i.e., polymer gels, which swell extensively in water. The most common hydrogels are polyelectrolyte gels: ...

  1. SANS studies of polymers

    International Nuclear Information System (INIS)

    Wignall, G.D.

    1985-01-01

    Some information provided by the application of small-angle neutron scattering concerning polymer structure is reviewed herein. Information about the polymer structure as examined in H 2 O/D 2 O mixtures is also provided. Examples of results of experiments performed at the National Center for Small-Angle Scattering Research are included

  2. Polymer based tunneling sensor

    Science.gov (United States)

    Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

    2006-01-01

    A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

  3. Polymers for Combating Biocorrosion

    Directory of Open Access Journals (Sweden)

    Jing Guo

    2018-03-01

    Full Text Available Biocorrosion has been considered as big trouble in many industries and marine environments due to causing of great economic loss. The main disadvantages of present approaches to prevent corrosion include being limited by environmental factors, being expensive, inapplicable to field, and sometimes inefficient. Studies show that polymer coatings with anticorrosion and antimicrobial properties have been widely accepted as a novel and effective approach to prevent biocorrosion. The main purpose of this review is to summarize up the progressive status of polymer coatings used for combating microbial corrosion. Polymers used to synthesize protective coatings are generally divided into three categories: (i traditional polymers incorporated with biocides, (ii antibacterial polymers containing quaternary ammonium compounds, and (iii conductive polymers. The strategies to synthesize polymer coatings resort mainly to grafting antibacterial polymers from the metal substrate surface using novel surface-functionalization approaches, such as free radical polymerization, chemically oxidative polymerization, and surface-initiated atom transfer radical polymerization, as opposed to the traditional approaches of dip coating or spin coating.

  4. Polymer light emitting diodes

    International Nuclear Information System (INIS)

    Gautier-Thianche, Emmmanuelle

    1998-01-01

    We study sandwich type semiconducting polymer light emitting diodes; anode/polymer/cathode. ITO is selected as anode, this polymer is a blend of a commercially available polymer with a high hole transport ability: polyvinyl-carbazole and a laser dye: coumarin-515. Magnesium covered with silver is chosen for the anode. We study the influence of polymer thickness and coumarin doping ratio on electroluminescence spectrum, electric characteristics and quantum efficiency. An important drawback is that diodes lifetime remains low. In the second part of our study we determine degradations causes with X-Ray reflectivity experiments. It may be due to ITO very high roughness. We realize a new type of planar electroluminescent device: a channel type electroluminescent device in which polymer layer is inserted into an aluminium channel. Such a device is by far more stable than using classical sandwich structures with the same polymer composition: indeed, charges are generated by internal-field ionization and there is no injection from the electrode to the polymer. This avoids electrochemical reactions at electrodes, thus reducing degradations routes. (author) [fr

  5. Polymers targeting habitual diseases

    Science.gov (United States)

    The use of polymeric drug conjugates mainly for the treatment for cancer therapy has been addressed, but these polymers also find their way in treatment of various lifestyle disorders like diabetes, hypertension, cardiovascular diseases etc. The focus is being laid to develop biodegradable polymer ...

  6. Stiff quantum polymers

    OpenAIRE

    Kleinert, H.

    2009-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  7. Conducting polymer hydrogels

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav

    2017-01-01

    Roč. 71, č. 2 (2017), s. 269-291 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : aerogel * conducting polymers * conductivity Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  8. Characterization of crystalline structures in Opuntia ficus-indica

    OpenAIRE

    Contreras-Padilla, Margarita; Rivera-Muñoz, Eric M.; Gutiérrez-Cortez, Elsa; del López, Alicia Real; Rodríguez-García, Mario Enrique

    2014-01-01

    This research studies the crystalline compounds present in nopal (Opuntia ficus-indica) cladodes. The identification of the crystalline structures was performed using X-ray diffraction, scanning electron microscopy, mass spectrometry, and Fourier transform infrared spectroscopy. The crystalline structures identified were calcium carbonate (calcite) [CaCO3], calcium-magnesium bicarbonate [CaMg(CO3)2], magnesium oxide [MgO], calcium oxalate monohydrate [Ca(C2O4)•(H2O)], potassium peroxydiphosph...

  9. Dangling bonds and crystalline inclusions in amorphous materials

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, L [Ferrara Univ. (Italy). Ist. di Matematica; Russo, G [Bologna Univ. (Italy). Ist. di Fisica

    1981-02-07

    It is suggested that on the surface of crystalline inclusions dangling bond formation is favoured due to unbalanced local stresses. The energy for bond tearings is probably originated from the exothermic process leading to the crystalline inclusion configuration which is more stable than the original amorphous one. A thermodynamical calculation is performed giving the ratio nsub(k) of crystalline inclusions having k dangling bonds on their surface.

  10. Used Fuel Disposition in Crystalline Rocks: FY16 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kalinina, Elena Arkadievna [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, T. [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, W. [Argonne National Lab. (ANL), Argonne, IL (United States); Buck, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Eittman, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tinnacher, R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tournassat, Christophe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Davis, J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Viswanathan, H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dittrich, T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hyman, F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karra, S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Makedonska, N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reimus, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Joseph, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-21

    The objective of the Crystalline Disposal R&D Work Package is to advance our understanding of long-term disposal of used fuel in crystalline rocks and to develop necessary experimental and computational capabilities to evaluate various disposal concepts in such media. FY16 continued to be a successful year in both experimental and modeling arenas in evaluation of used fuel disposal in crystalline rocks. The work covers a wide range of research topics identified in the R&D plan.

  11. United States Crystalline Repository Project - key research areas

    International Nuclear Information System (INIS)

    Patera, E.S.

    1986-01-01

    The Crystalline Repository Project is responsible for siting the second high-level nuclear waste repository in crystalline rock for the US Department of Energy. A methodology is being developed to define data and information needs and a way to evaluate that information. The areas of research the Crystalline Repository Project is involved in include fluid flow in a fractured network, coupled thermal, chemical and flow processes and cooperation in other nations and OECD research programs

  12. Effects of blending poly(D,L-lactide) with poly(ethylene glycol) on the higher-order crystalline structures of poly(ethylene glycol) as revealed by small-angle X-ray scattering

    International Nuclear Information System (INIS)

    Tien, N D; Kimura, G; Yamashiro, Y; Fujiwara, H; Sasaki, S; Sakurai, S; Hoa, T P; Mochizuki, M

    2011-01-01

    Effects of blending poly(lactic acid) (PLA) with poly(ethylene glycol) (PEG) on higher-order crystalline structures of PEG were examined using small-angle X-ray scattering (SAXS). For this purpose, the fact that two polymers are both crystalline makes situtation much complicated. To simplify, non-crystalline PLA is suitable. Thus, we used poly(D,L-lactic acid) (DLPLA), which is random copolymer comprising D- and L-lactic acid moieties. Multiple scattering peaks arising from the regular crystalline lamellar structure were observed for the PEG homopolymer and the blends. Surprisingly, the structure is much more regular for the blend DLPLA/PEG at composition of 20/80 wt.% than for the PEG homopolymer. Also for this blend sample as well as for a PEG homopolymer, very peculiar SAXS profiles were observed just 1 deg. C below T m of PEG. This is found to be a particle scattering of plate-like objects, which has never been reported for polymer blends or crystalline polymers. Futhermore, it was found that there was strong hysteresis of the higher-order structure formation.

  13. Ortho-positronium annihilation parameters in polyvinyl alcohol films with various degrees of polymerization, saponification and crystallinity

    International Nuclear Information System (INIS)

    Muramatsu, Hisakazu; Matsumoto, Kuniyuki; Minekawa, Sachiko; Yagi, Yukiko; Sasai, Shigenori

    2001-01-01

    Positron annihilation lifetime (PAL) spectroscopy has been applied to polyvinyl alcohol (PVA) films prepared with commercially available PVA or from polyvinyl acetate (PVac). The variation of lifetimes of ortho-positronium (o-Ps) formed in the films was investigated as a function of the degrees of polymerization, saponification, or crystallinity. For the fully saponificated samples, no dependence was found to exist on the degrees of polymerization or of crystallinity. For the partially saponificated samples, however, the dependence of the o-Ps lifetime on the degree of saponification was clearly observed, and this is explained by both the formation of hydrogen bonds among the polymer chains and the existence of acetyl group strongly inhibiting the hydrogen-bond formation due to steric hindrance. (orig.)

  14. Theory of polymer blends

    International Nuclear Information System (INIS)

    Curro, J.G.; Schweizer, K.S.

    1989-01-01

    We have recently developed a new theoretical approach to the study of polymer liquids. The theory is based on the ''reference interaction site model'' (RISM theory) of Chandler and Andersen, which has been successful in describing the structure of small molecule liquids. We have recently extended our polymer RISM theory to the case of polymer blends. In the present investigation we have applied this theory to two special binary blends: (1) the athermal mixture where we isolate structural effects, and (2) the isotopic mixture in which structurally identical polymer chains interact with dissimilar attractive interactions. By studying these two special cases we are able to obtain insights into the molecular factors which control the miscibility in polymer mixtures. 18 refs., 2 figs

  15. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials...... are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...... is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

  16. All Polymer Micropump

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen

    2008-01-01

    In this thesis an all polymer micropump, and the fabrication method required to fabricate this, are examined. Polymer microfluidic. devices are of major scientific interest because they can combine complicated chemical and biological analys~s in cheap and disposable devices. The electrode system...... in the micropump is based on the conducting polymer poly(3,4 ethylenedioxythiophene) (PEDOT). The majority of the work conducted was therefore aimed at developing methods for patterning and processing PEDOT. First a method was developed, where the conducting polymer PEDOT can be integrated into non...... of the substrate, the PEDOT is integrated into the non-conductive polymer. The result is a material that retains the good conductivity of PEDOT, but gains the mechanical stability of the substrate. The best results were obtained for PEDOTjPMMA. The new mechanically stable PEDOTjPMMA was micro-patterned using clean...

  17. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  18. Differential scanning calorimetry (DSC) of semicrystalline polymers.

    Science.gov (United States)

    Schick, C

    2009-11-01

    Differential scanning calorimetry (DSC) is an effective analytical tool to characterize the physical properties of a polymer. DSC enables determination of melting, crystallization, and mesomorphic transition temperatures, and the corresponding enthalpy and entropy changes, and characterization of glass transition and other effects that show either changes in heat capacity or a latent heat. Calorimetry takes a special place among other methods. In addition to its simplicity and universality, the energy characteristics (heat capacity C(P) and its integral over temperature T--enthalpy H), measured via calorimetry, have a clear physical meaning even though sometimes interpretation may be difficult. With introduction of differential scanning calorimeters (DSC) in the early 1960s calorimetry became a standard tool in polymer science. The advantage of DSC compared with other calorimetric techniques lies in the broad dynamic range regarding heating and cooling rates, including isothermal and temperature-modulated operation. Today 12 orders of magnitude in scanning rate can be covered by combining different types of DSCs. Rates as low as 1 microK s(-1) are possible and at the other extreme heating and cooling at 1 MK s(-1) and higher is possible. The broad dynamic range is especially of interest for semicrystalline polymers because they are commonly far from equilibrium and phase transitions are strongly time (rate) dependent. Nevertheless, there are still several unsolved problems regarding calorimetry of polymers. I try to address a few of these, for example determination of baseline heat capacity, which is related to the problem of crystallinity determination by DSC, or the occurrence of multiple melting peaks. Possible solutions by using advanced calorimetric techniques, for example fast scanning and high frequency AC (temperature-modulated) calorimetry are discussed.

  19. Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Y., E-mail: maekawa.yasunari@jaea.go.jp [Japan Atomic Energy Agency (JAEA), Quantum Beam Science Directorate, High Performance Polymer Group, 1233 Watanuki-Machi, Takasaki, Gunma-ken 370-1292 (Japan)

    2010-07-01

    Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

  20. Introduction of Functional Structures in Nano-Scales into Engineering Polymer Films Using Radiation Technique

    International Nuclear Information System (INIS)

    Maekawa, Y.

    2010-01-01

    Introduction of functional regions in nanometer scale in polymeric films using γ-rays, EB, and ion beams are proposed. Two approaches to build nano-scale functional domains in polymer substrates are proposed: 1) Radiation-induced grafting to transfer nano-scale polymer crystalline structures (morphology), acting as a nano-template, to nano-scale graft polymer regions. The obtained polymers with nano structures can be applied to high performance polymer membranes. 2) Fabrication of nanopores and functional domains in engineering plastic films using ion beams, which deposit the energy in very narrow region of polymer films. Hydrophilic grafting polymers are introduced into hydrophobic fluorinated polymers, cross-linked PTFE (cPTFE) and aromatic hydrocarbon polymer, poly(ether ether ketone (PEEK), which is known to have lamella and crystallite in the polymer films. Then, the hierarchical structures of graft domains are analyzed by a small angle neutron scattering (SANS) experiment. From these analyses, the different structures and the different formation of graft domains were observed in fluorinated and hydrocarbon polymer substrates. the grafted domains in the cPTFE film, working as an ion channel, grew as covering the crystallite and the size of domain seems to be similar to that of crystallite. On the other hand, the PEEK-based PEM has a smaller domain size and it seems to grow independently on the crystallites of PEEK substrate. For nano-fabrication of polymer films using heavy ion beams, the energy distribution in radial direction, which is perpendicular to ion trajectory, is mainly concerned. For penumbra, we re-estimated effective radius of penumbra, in which radiation induced grafting took place, for several different ion beams. We observed the different diameters of the ion channels consisting of graft polymers. The channel sizes were quite in good agreement with the effective penumbra which possess the absorption doses more than 1 kGy. (author)

  1. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Weizierl, Barbara; Wester, Ture

    2001-01-01

    Artikel på CD-Rom 8 sider. The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells...... with fivefold symmetry in 3D space. The quasi-crystal geometry can be constructed from two different cubic cells with identical rhombic facets, where the relation between the diagonals is the golden section. All cells have identical rhombic faces, identical edges and identical icosahedral/dedecahedral nodes....... The purpose of the paper is to investigate some possibilities for the application of Quasi-Crystal geometry for structures in architecture. The basis for the investigations is A: to use the Golden Cubes (the two different hexahedra consisting of rhombic facets where the length of the diagonals has the Golden...

  2. (Preoxidation cleaning optimization for crystalline silicon)

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    A series of controlled experiments has been performed in Sandia's Photovoltaic Device Fabrication Laboratory to evaluate the effect of various chemical surface treatments on the recombination lifetime of crystalline silicon wafers subjected to a high-temperature dry oxidation. From this series of experiments we have deduced a relatively simple yet effective cleaning sequence. We have also evaluated the effect of different chemical damage-removal etches for improving the recombination lifetime and surface smoothness of mechanically lapped wafers. This paper presents the methodology used, the experimental results obtained, and our experience with using this process on a continuing basis over a period of many months. 7 refs., 4 figs., 1 tab.

  3. Ground Water movement in crystalline rock aquifers

    International Nuclear Information System (INIS)

    Serejo, A.N.C.; Freire, C.; Siqueira, H.B. de; Frischkorn, H.; Torquato, J.R.F.; Santiago, M.M.F.; Barbosa, P.C.

    1984-01-01

    Ground water movement studies were performed in crystalline rock aquifers from the upper Acarau River hydrographic basin, state of Ceara, Brazil. The studies included carbon-14, 18 O/ 16 O and tritium measurements as well as chemical analysis. A total of 35 wells were surveyed during drought seasons. Carbon-14 values displayed little variation which implied that the water use was adequate despite of the slower recharge conditions. Fairly constant isotopic 18 O/ 16 O ratio values in the wells and their similarity with rainwater values indicated that the recharge is done exclusively by pluvial waters. A decreasing tendency within the tritium concentration values were interpreted as a periodic rainwater renewal for these aquifers. The chemical analysis demonstrated that there is in fact no correlation between salinity and the time the water remains in the aquifer itself. (D.J.M.) [pt

  4. Mass transport in non crystalline metallic alloys

    International Nuclear Information System (INIS)

    Limoge, Y.

    1986-08-01

    In order to improve our understanding of mass transport in non crystalline metallic alloys we have developed indirect studies of diffusion based on electron irradiation and hydrostatic pressure effects upon crystallization. In a first part we present the models of crystallization which are used, then we give the experimental results. The main point is the first experimental measurement of the activation volume for diffusion in a metallic glass: the value of which is roughly one atomic volume. We show also recent quantitative results concerning radiation enhanced diffusion in metallic glasses (FeNi) 8 (PB) 2 and Ni 6 Nb 4 . In a last part we discuss the atomic model needed to explain our results

  5. Nitrogen in highly crystalline carbon nanotubes

    International Nuclear Information System (INIS)

    Ducati, C; Koziol, K; Stavrinadis, A; Friedrichs, S; Windle, A H; Midgley, P A

    2006-01-01

    Multiwall carbon nanotubes (MWCNTs) with an unprecedented degree of internal order were synthesised by chemical vapour deposition (CVD) adding a nitrogen-containing compound to the hydrocarbon feedstock. Ferrocene was used as the metal catalyst precursor. The remarkable crystallinity of these nanotubes lies both in the isochirality and in the crystallographic register of their walls, as demonstrated by electron diffraction and high resolution electron microscopy experiments. High resolution transmission electron microscopy analysis shows that the walls of the nanotubes consist of truncated stacked cones, instead of perfect cylinders, with a range of apex angles that appears to be related to the nitrogen concentration in the synthesis process. The structure of armchair, zigzag and chiral nanotubes is modelled and discussed in terms of density of topological defects, providing an interesting comparison with our microscopy experiments. A growth mechanism based on the interplay of base- and tip-growth is proposed to account for our experimental observations

  6. Liquid crystalline order of carbon nanotubes

    Science.gov (United States)

    Georgiev, Georgi; Ahlawat, Aditya; Mulkern, Brian; Doyle, Robert; Mongeau, Jennifer; Ogilvie, Alex

    2007-03-01

    Topological defects formed during phase transitions in liquid crystals provide a direct proof of the standard Cosmological model and are direct links to the Early Universe. On the other hand in Nanotechnology, carbon nanotubes can be manipulated and oriented directly by changing the liquid crystalline state of the nanotubes, in combination with organic liquid crystals. Currently there are no nano-assemblers, which makes the liquid crystal state of the nanotubes, one of the few ways of controlling them. We show the design of a fast and efficient polarized light ellipsometric system (a new modification of previous optical systems) that can provide fast quantitative real time measurements in two dimensions of the formation of topological defects in liquid crystals during phase transitions in lab settings. Our aim is to provide fundamental information about the formation of optically anisotropic structures in liquid crystals and the orientation of carbon nanotubes in electric field.

  7. Radionuclide migration in crystalline rock fractures

    International Nuclear Information System (INIS)

    Hoelttae, P.

    2002-01-01

    Crystalline rock has been considered as a host medium for the repository of high radioactive spent nuclear fuel in Finland. The geosphere will act as an ultimate barrier retarding the migration of radionuclides to the biosphere if they are released through the technical barriers. Radionuclide transport is assumed to take place along watercarrying fractures, and retardation will occur both in the fracture and within the rock matrix. To be able to predict the transport and retardation of radionuclides in rock fractures and rock matrices, it is essential to understand the different phenomena involved. Matrix diffusion has been indicated to be an important mechanism, which will retard the transport of radionuclides in rock fractures. Both dispersion and matrix diffusion are processes, which can have similar influences on solute breakthrough curves in fractured crystalline rock. In this work, the migration of radionuclides in crystalline rock fractures was studied by means of laboratory scale column methods. The purpose of the research was to gain a better understanding of various phenomena - particularly matrix diffusion - affecting the transport and retardation behaviour of radionuclides in fracture flow. Interaction between radionuclides and the rock matrix was measured in order to test the compatibility of experimental retardation parameters and transport models used in assessing the safety of underground repositories for spent nuclear fuel. Rock samples of mica gneiss and of unaltered, moderately altered and strongly altered tonalite represented different rock features and porosities offering the possibility to determine experimental boundary limit values for parameters describing both the transport and retardation of radionuclides and rock matrix properties. The dominant matrix diffusion behaviour was demonstrated in porous ceramic column and gas diffusion experiments. Demonstration of the effects of matrix diffusion in crystalline rock fracture succeeded for the

  8. Semiclassical and quantum polarons in crystalline acetanilide

    Science.gov (United States)

    Hamm, P.; Tsironis, G. P.

    2007-08-01

    Crystalline acetanilide is a an organic solid with peptide bond structure similar to that of proteins. Two states appear in the amide I spectral region having drastically different properties: one is strongly temperature dependent and disappears at high temperatures while the other is stable at all temperatures. Experimental and theoretical work over the past twenty five years has assigned the former to a selftrapped state while the latter to an extended free exciton state. In this article we review the experimental and theoretical developments on acetanilide paying particular attention to issues that are still pending. Although the interpretation of the states is experimentally sound, we find that specific theoretical comprehension is still lacking. Among the issues that that appear not well understood is the effective dimensionality of the selftrapped polaron and free exciton states.

  9. Nanodefects in ultrahard crystalline cubic boron nitride

    International Nuclear Information System (INIS)

    Nistor, S. V.; Stefan, M.; Goovaerts, E.; Schoemaker, D.

    2002-01-01

    Cubic boron nitride (cBN), the second hardest known material after diamond, exhibits high thermal conductivity and an excellent ability to be n or p doped, which makes it a strong candidate for the next generation of high-temperature micro optical and micro electronic devices. According to recent studies, cBN exhibits a better resistance to radiation damage than diamond, which suggests potential applications in extreme radiation environments. Crystalline cBN powders of up to 0.5 mm linear size is obtained in a similar way as diamond, by catalytic conversion of hexagonal BN (hBN) to cBN at even higher pressures (> 5GPa) and temperatures (∼ 1900 K). Considering the essential role played by the nanodefects (point defects and impurities) in determining its physical properties, it is surprising how limited is the amount of published data concerning the properties of nanodefects in this material, especially by Electron Paramagnetic Resonance (EPR) spectroscopy, the most powerful method for identification and characterization of nanodefects in both insulators and semiconductors. This seems to be due mainly to the absence of natural cBN gems and the extreme difficulties in producing even mm 3 sized synthetic crystals. We shall present our recent EPR studies on cBN crystalline powders, performed in a broad temperature range from room temperature (RT) down to 1.2 K on several sorts of large size cBN powder grits of yellow and amber color for industrial applications. Previous multifrequency (9.3 GHz and 95 GHz) EPR studies of brown to black cBN crystallites prepared with excess of boron, resulted in the discovery of two new types of paramagnetic point defects with different spectral properties, called the D1 and D2 centers. Our X(9.3 GHz)-band EPR investigations resulted in the observation in amber cBN crystalline powders of a spectrum with a strong temperature dependence of the lineshape. It was found that for high and low temperatures, respectively, the numerical

  10. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    International Nuclear Information System (INIS)

    Walker, D.D.

    1999-01-01

    Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A ampersand 038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports

  11. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  12. Nonlinear optics of liquid crystalline materials

    International Nuclear Information System (INIS)

    Khoo, Iam Choon

    2009-01-01

    Liquid crystals occupy an important niche in nonlinear optics as a result of their unique physical and optical properties. Besides their broadband birefringence and transparency, abilities to self-assemble into various crystalline phases and to conform to various flexible forms and shapes, liquid crystals are compatible with almost all other optoelectronic materials and technology platforms. In both isotropic and ordered phases, liquid crystals possess extraordinarily large optical nonlinearities that stretch over multiple time scales. To date, almost all conceivable nonlinear optical phenomena have been observed in a very broad spectrum spanning the entire visible to infrared and beyond. In this review, we present a self-contained complete discussion of the optical nonlinearities of liquid crystals, and a thorough review of a wide range of nonlinear optical processes and phenomena enabled by these unique properties. Starting with a brief historical account of the development of nonlinear optical studies of the mesophases of liquid crystals, we then review various liquid crystalline materials and structures, and their nonlinear optical properties. Emphasis is placed on the nematic phase, which best exemplifies the dual nature of liquid crystals, although frequent references to other phases are also made. We also delve into recent work on novel structures such as photonic crystals, metamaterials and nanostructures and their special characteristics and emergent properties. The mechanisms and complex nonlocal dynamics of optical nonlinearities associated with laser induced director axis reorientation, thermal, density, and order parameter fluctuations, space charge field formation and photorefractivity are critically reviewed as a foundation for the discussions of various nonlinear optical processes detailed in this paper

  13. Quantum vibrational polarons: Crystalline acetanilide revisited

    Science.gov (United States)

    Hamm, Peter; Edler, Julian

    2006-03-01

    We discuss a refined theoretical description of the peculiar spectroscopy of crystalline acetanilide (ACN). Acetanilide is a molecular crystal with quasi-one-dimensional chains of hydrogen-bonded units, which is often regarded as a model system for the vibrational spectroscopy of proteins. In linear spectroscopy, the CO stretching (amide I) band of ACN features a double-peak structure, the lower of which shows a pronounced temperature dependence which has been discussed in the context of polaron theory. In nonlinear spectroscopy, both of these peaks respond distinctly differently. The lower-frequency band exhibits the anharmonicity expected from polaron theory, while the higher-frequency band responds as if it were quasiharmonic. We have recently related the response of the higher-frequency band to that of a free exciton [J. Edler and P. Hamm, J. Chem. Phys. 117, 2415 (2002)]. However, as discussed in the present paper, the free exciton is not an eigenstate of the full quantum version of the Holstein polaron Hamiltonian, which is commonly used to describe these phenomena. In order to resolve this issue, we present a numerically exact solution of the Holstein polaron Hamiltonian in one dimension (1D) and 3D. In 1D, we find that the commonly used displaced oscillator picture remains qualitatively correct, even for relatively large exciton coupling. However, the result is not in agreement with the experiment, as it fails to explain the free-exciton band. In contrast, when taking into account the 3D nature of crystalline acetanilide, certain parameter regimes exist where the displaced oscillator picture breaks down and states appear in the spectrum that indeed exhibit the characteristics of a free exciton. The appearance of these states is a speciality of vibrational polarons, whose source of exciton coupling is transition dipole coupling which is expected to have opposite signs of interchain and intrachain coupling.

  14. Polymer Vesicles as Robust Scaffolds for the Directed Assembly of Highly Crystalline Nanocrystals †

    KAUST Repository

    Wang, Mingfeng; Zhang, Meng; Siegers, Conrad; Scholes, Gregory D.; Winnik, Mitchell A.

    2009-01-01

    population when the NPs were present. The vesicle fraction could be isolated by selective sedimentation via centrifugation, followed by redispersion in water. The NPs appeared to be incorporated into the PAA layers on the internal and external walls

  15. Liquid crystalline polymers from renewable resources: Synthesis, characterization, and applications in composites.

    NARCIS (Netherlands)

    Wilsens, Karel

    2017-01-01

    Thermotropic polyesters are an important class of materials for high erformance applications. Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compression-molded

  16. Structure-Function Relationships of Ferroelectric Polymers.

    Science.gov (United States)

    Pavlopoulou, Eleni; Maiz, Jon; Spampinato, Nicoletta; Maglione, Mario; Hadziioannou, Georges

    Poly(vinylidene fluoride), PVDF, and its copolymers with trifluoroethylene, P(VDF-co-TrFE) have been long appreciated for their excellent ferroelectric properties. Although they have been mainly studied in the 80s and 90s, understanding their performance is still lacking. Yet the increasing use of P(VDF-co-TrFE) thin films in organic electronic devices during the last ten years revives the need for apprehending the function of these materials. In this work we investigate the structure of P(VDF-co-TrFE) films and correlate it to their ferroelectric properties. Our results show that ferroelectric performance is solely driven by the fraction of polymer that has been crystallized in the ferroelectric phases of PVDF. The relations between remnant polarization, coercive field and dipole switching rate of P(VDF-co-TrFE) with the ferroelectric crystallinity are demonstrated. The French Research Agency (ANR), the Aquitaine Region, Arkema and STMicroelectronics are kindly acknowledged for financial support.

  17. Investigation of nanoscale reinforcement into textile polymers

    Science.gov (United States)

    Khan, Mujibur Rahman

    Microscope), and mechanical tests. Phenomenal improvement in properties was found; modulus, strength, fracture strain, and elastic energy increased by 219%, 100%, 107%, and 88%, respectively before strain hardening. Once strain hardened the strength, modulus and elastic energy increased by almost one order of magnitude. Source of these improvements were traced to increase in crystallinity and rate of crystallization, formation of microdroplets as a minor phase, sliding between minor and major phases, coating of nanotubes with polymer and alignment of nanotubes.

  18. Inelastic neutron scattering from synthetic and biological polymers

    International Nuclear Information System (INIS)

    White, J.W.

    1976-01-01

    Neutron elastic and inelastic scattering measurements have provided many unique insights into structure, and by reviewing progress on synthetics, important differences likely to arise in biological systems are identified and a direction for studies of the latter is suggested. By neutron inelastic scattering it is possible to measure the frequency of thermally excited interatomic and intermolecular vibrations in crystals. With perfect organic and inorganic crystals the technique is now classical and has given great insight into the crystal forces responsible for the observed structures as well as the phase transitions they undergo. The study of polymer crystals immediately presents two problems of disorder: (1) Macroscopic disorder arises because the sample is a mixture of amorphous and crystalline fractions, and it may be acute enough to inhibit growth of a single crystal large enough for neutron studies. (2) Microscopic disorder in the packing of polymer chains in the ''crystalline'' regions is indicated by broadening of Bragg peaks. Both types of disorder problem arise in biological systems. The methods by which they were partially overcome to allow neutron measurements with synthetic polymers are described but first a classical example of the determination of interatomic forces by inelastic neutron scattering is given

  19. Time dependent mechanical modeling for polymers based on network theory

    Energy Technology Data Exchange (ETDEWEB)

    Billon, Noëlle [MINES ParisTech, PSL-Research University, CEMEF – Centre de mise en forme des matériaux, CNRS UMR 7635, CS 10207 rue Claude Daunesse 06904 Sophia Antipolis Cedex (France)

    2016-05-18

    Despite of a lot of attempts during recent years, complex mechanical behaviour of polymers remains incompletely modelled, making industrial design of structures under complex, cyclic and hard loadings not totally reliable. The non linear and dissipative viscoelastic, viscoplastic behaviour of those materials impose to take into account non linear and combined effects of mechanical and thermal phenomena. In this view, a visco-hyperelastic, viscoplastic model, based on network description of the material has recently been developed and designed in a complete thermodynamic frame in order to take into account those main thermo-mechanical couplings. Also, a way to account for coupled effects of strain-rate and temperature was suggested. First experimental validations conducted in the 1D limit on amorphous rubbery like PMMA in isothermal conditions led to pretty goods results. In this paper a more complete formalism is presented and validated in the case of a semi crystalline polymer, a PA66 and a PET (either amorphous or semi crystalline) are used. Protocol for identification of constitutive parameters is described. It is concluded that this new approach should be the route to accurately model thermo-mechanical behaviour of polymers using a reduced number of parameters of some physical meaning.

  20. Polymer-Assisted Hydrothermal Synthesis of Hierarchically Arranged Hydroxyapatite Nanoceramic

    Directory of Open Access Journals (Sweden)

    A. Joseph Nathanael

    2013-01-01

    Full Text Available Flower-like hydroxyapatite (HA nanostructures were synthesized by a polymer-assisted hydrothermal method. The thickness of the petals/plates decreased from 200 nm to 40 nm as the polymer concentration increased. The thickness also decreased as the hydrothermal treatment time increased from 6 to 12 hr. The HRTEM and SAED patterns suggest that the floral-like HA nanostructures are single crystalline in nature. Structural analysis based on XRD and Raman experiments implied that the produced nanostructure is a pure form of HA without any other impurities. The possible formation mechanism was discussed for the formation of flower-like HA nanostructures during polymer-assisted hydrothermal synthesis. Finally, in vitro cellular analysis revealed that the hierarchically arranged HA nanoceramic had improved cell viability relative to other structures. The cells were actively proliferated over these nanostructures due to lower cytotoxicity. Overall, the size and the crystallinity of the nanostructures played a role in improving the cell proliferation.

  1. Photoluminescence in conjugated polymers

    International Nuclear Information System (INIS)

    Furst, J.E.; Laugesen, R.; Dastoor, P.; McNeill, C.

    2002-01-01

    Full text: Conjugated polymers combine the electronic and optical properties of semiconductors with the processability of polymers. They contain a sequence of alternate single and double carbon bonds so that the overlap of unhybridised p z orbitals creates a delocalised ρ system which gives semiconducting properties with p-bonding (valence) and p* -antibonding (conduction) bands. Photoluminesence (PL) in conjugated polymers results from the radiative decay of singlet excitons confined to a single chain. The present work is the first in a series of studies in our laboratory that will characterize the optical properties of conjugated polymers. The experiment involves the illumination of thin films of conjugated polymer with UV light (I=360 nm) and observing the subsequent fluorescence using a custom-built, fluorescence spectrometer. Photoluminesence spectra provide basic information about the structure of the polymer film. A typical spectrum is shown in the accompanying figure. The position of the first peak is related to the polymer chain length and resolved multiple vibronic peaks are an indication of film structure and morphology. We will also present results related to the optical degradation of these materials when exposed to air and UV light

  2. Efectos del agregado de cachaza y de diferentes densidades de plantación en la capacidad productiva de un semillero saneado de la variedad de caña de azúcar (Saccharum spp. LCP85-384 Effects of filter cake incorporation and different planting densities on the productive capacity of a healthy LCP85-384 sugarcane variety (Saccharum spp. nursery

    Directory of Open Access Journals (Sweden)

    María I. Cuenya

    2007-06-01

    Full Text Available El alto valor agregado de la semilla saneada de caña de azúcar exige la implementación de diversos manejos culturales que potencien al máximo la productividad de los semilleros. Este trabajo evalúa diferentes alternativas de manejo en la plantación de semilla saneada por termoterapia de la variedad LCP85-384, combinando distintas densidades de yemas con el agregado o no de cachaza en la base del surco. Se implantó un ensayo en Parcelas Divididas con tres repeticiones. Las parcelas principales contemplaron el agregado o no de cachaza. Las subparcelas comprendieron las siguientes densidades de plantación por metro lineal de surco: tres, seis y nueve yemas uninodales; dos y tres trozos de tres yemas cada uno (2 x 3Y y 3 x 3Y, respectivamente y un tallo cortado al medio (8 a 10 yemas. En caña planta y soca 1 se evaluaron número de tallos/parcela, altura promedio de tallos, número de yemas/m lineal del tallo y número de yemas/parcela. Se efectuaron análisis de la varianza y pruebas de comparación de medias (DLS de Fisher. Se detectaron diferencias altamente significativas entre los subtratamientos con respecto al número total de tallos/parcela (caña planta y soca 1 y a la altura promedio de tallos (caña planta. Para ambas variables y en las dos edades de corte, los mayores valores se registraron para los subtratamientos que involucraron trozos de caña y los menores valores para aquellos originados de yemas individuales. Para el número total de yemas/parcela, producidas durante los dos años, se detectaron diferencias altamente significativas entre tratamientos principales y entre subtratamientos. Para esta última variable, de interés en un semillero con dos años de aprovechamiento, el subtratamiento de 3 x 3Y resultó la mejor alternativa de plantación, presentando diferencias significativas con el resto de las densidades ensayadas. La aplicación de cachaza en plantación resultó ventajosa cuando se consideró el

  3. Irradiation effects on polymer-model compounds

    International Nuclear Information System (INIS)

    Seguchi, Tadao; Hayakawa, Naohiro; Tamura, Naoyuki; Katsumura, Yosuke; Hayashi, Nariyuki; Tabata, Yoneho

    1991-01-01

    Irradiation effects on n-paraffins and squalane, used as models of polymers, were investigated by product analysis. Four n-paraffins, C 20 H 42 , C 21 H 44 , C 23 H 48 and C 24 H 50 , and squalane (C 30 H 62 ) were γ-irradiated under vacuum in liquid, crystalline and glassy states. The evolved gases were analyzed by gas chromatography and changes in molecular weight were analyzed by liquid chromatography and mass spectroscopy. G-values for crosslinking of n-paraffins were 1.2 for crystalline states (at 25 0 C) and 1.7 for liquid states (at 55 0 C), and showed no difference between odd and even carbon numbers. The G-value of liquid squalane was 1.7; it was 1.3 for the glassy state at low temperature (-77 0 C). Double bonds were common in the crosslinked products, especially after liquid-phase irradiation. The probability of chain scission was estimated as being negligible, though a small number of chain-scission products (which were products of scission at chain-ends or side chains) were observed by gas analysis. (author)

  4. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  5. SANS studies of polymers

    International Nuclear Information System (INIS)

    Wignall, G.D.

    1984-10-01

    Before small-angle neutron scattering (SANS), chain conformation studies were limited to light and small angle x-ray scattering techniques, usually in dilute solution. SANS from blends of normal and labeled molecules could give direct information on chain conformation in bulk polymers. Water-soluble polymers may be examined in H 2 O/D 2 O mixtures using contrast variation methods to provide further information on polymer structure. This paper reviews some of the information provided by this technique using examples of experiments performed at the National Center for Small-Angle Scattering Research (NCSASR)

  6. Development of Silicate Polymers

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

      The development of inorganic polymers is a new promising technology that may be used in many applications. The syntheses of inorganic polymers are normally carried out either by mixing an amorphous material for example silicium dioxide with a mineral base or dissolving metal oxids or metal...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

  7. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  8. A thermodynamic approach to model the caloric properties of semicrystalline polymers

    Science.gov (United States)

    Lion, Alexander; Johlitz, Michael

    2016-05-01

    It is well known that the crystallisation and melting behaviour of semicrystalline polymers depends in a pronounced manner on the temperature history. If the polymer is in the liquid state above the melting point, and the temperature is reduced to a level below the glass transition, the final degree of crystallinity, the amount of the rigid amorphous phase and the configurational state of the mobile amorphous phase strongly depend on the cooling rate. If the temperature is increased afterwards, the extents of cold crystallisation and melting are functions of the heating rate. Since crystalline and amorphous phases exhibit different densities, the specific volume depends also on the temperature history. In this article, a thermodynamically based phenomenological approach is developed which allows for the constitutive representation of these phenomena in the time domain. The degree of crystallinity and the configuration of the amorphous phase are represented by two internal state variables whose evolution equations are formulated under consideration of the second law of thermodynamics. The model for the specific Gibbs free energy takes the chemical potentials of the different phases and the mixture entropy into account. For simplification, it is assumed that the amount of the rigid amorphous phase is proportional to the degree of crystallinity. An essential outcome of the model is an equation in closed form for the equilibrium degree of crystallinity in dependence on pressure and temperature. Numerical simulations demonstrate that the process dependences of crystallisation and melting under consideration of the glass transition are represented.

  9. LIQUID CRYSTALLINE BEHAVIOR OF HYDROXYPROPYL CELLULOSE ESTERIFIED WITH 4-ALKOXYBENZOIC ACID.

    Directory of Open Access Journals (Sweden)

    Yehia Fahmy

    2010-07-01

    Full Text Available A series of 4- alkyoxybenzoyloxypropyl cellulose (ABPC-n samples was synthesized via the esterification of hydroxypropyl cellulose (HPC with 4-alkoxybenzoic acid bearing different numbers of carbon atoms. The molecular structure of the ABPC-n was confirmed by Fourier transform infrared (FT-IR spectroscopy and 1H NMR spectroscopy. The liquid crystalline (LC phases and transitions behaviors were investigated using differential scanning calorimetry (DSC, polarized light microscopy (PLM, and refractometry. It was found that the glass transition (Tg and clearing (Tc temperatures decrease with increase of the alkoxy chain length. It was observed that the derivatives with an odd number of carbon atoms are non-mesomorphic. This series of ABPC-n polymers exhibit characteristic features of cholesteric LC phases between their glass transition and isotropization temperatures.

  10. Synthesis, Characterization and Photoinduction of Optical Anisotropy in Liquid Crystalline Diblock Azo-Copolymers

    DEFF Research Database (Denmark)

    Forcén, P; Oriol, L; Sánchez, C

    2007-01-01

    Diblock copolymers with polymethyl methacrylate and side chain liquid crystalline WC) azopolymethacrylate blocks were synthesized by atom transfer radical polymerization (ATRP). The azobeazene content in these copolymers ranges from 52 to 7 wt %. For an azo conteat dowri to 20% they exhibit a LC...... anisotropy induced in these films by illumination with linearly polarized 488 nm light was studied and the resuits compared with those of the azo homopolymer and of a random copolymer with a similar composition. The formation of azo aggregates inside the azo blocks is strongly reduced in going from...... the homopolymer to the copolymers. Photoinduced azo orientation perpendicular to the 488 nm light polarization was found in aH the polymers. The orientational order parameter is very similar in the homopolymer and in the block copolymers with an azo content down to 20 wt %, while it is much lower in the random...

  11. The distribution of sorbed moisture within a partially crystalline cellulosic web of fibres (paper)

    International Nuclear Information System (INIS)

    Garvey, C.; Parker, I.H.; Simon, G.

    1999-01-01

    Full text: Paper is a hydrophilic web of partially crystalline cellulosic fibres. In conditions of changing humidity it will sorb/desorb moisture. It has been found by dielectric relaxation spectroscopy and two dimensional nuclear magnetic resonance spectroscopy that the sorption of water causes the activation of long range co-operative molecular motions by lowering the glass transition temperature into normal ambient range. Water therefore acts as a plasticiser. NMR also indicates that the water is not uniformly distributed within the paper matrix. Preliminary experiments have been performed using the AUSANS instrument to investigate the distribution of sorbed water with the eventual aim of understanding how sorbed water is mixed within the paper sheet. Samples of paper with varying polymer morphology have been selectively deuterated by allowing to equilibrate with known D 2 O humidities. The results are discussed within the context of the AUSANS instrument

  12. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    respective ground states decide the conformational statistics of the polymer. For semiflexible polymers, the relevant non-dimensional quantity is lp/L, where lp is the persistence length (which is proportional to the bending modulus k) and L is the contour length of the polymer. In the limit, lp/L ≪ 1, the polymer behaves as.

  13. Direct Coupling of Electron Beam Irradiation and Polymer Extrusion for a Continuous Polymer Modification in Molten State

    International Nuclear Information System (INIS)

    Stephan, M.

    2006-01-01

    The new approach of an e-beam initiating of chemical reactions in polymers in molten state results in some innovative results. High temperature, intensive macromolecular mobility and the absence of any crystallinity are some reasons for achieving unexpected structures, processing behaviour and properties changes in such treated thermoplastics and rubbers. Examples are a much more effective crosslinking of polyethylene and special rubbers, long chain branching of polypropylene or a partial crosslinking of polysulfone. Additionally, most of these modification effects are also achievable by a direct coupling of electron beam irradiation and conventional polymer extrusion processing for a continuous polymer modification in molten state. For realizing this unique processing technique a special MOBILE RADIATION FACILITY (MOBRAD1/T) was designed, constructed and manufactured in the IPF Dresden at which a lab-scale single screw extruder was adapted direct to an electron beam accelerator to realize a prompt irradiation of extruded polymer melt profiles before there solidification. Surprisingly, as a result of these short-time-melt reactions some effective and new polymer modification effects were found and will be presented

  14. Fourier transform infrared spectroscopic estimation of crystallinity in ...

    Indian Academy of Sciences (India)

    Wintec

    The crystallinity parameter is calculated by using a standard procedure which can be used to estimate the distribution of quartz in various rocks for mining purpose. The infrared ... The X-ray diffraction full ... crystallinity and trace mineral components of rocks (Partha- ... infrared techniques (Rice et al 1995). ... The absorption.

  15. Proceedings of the workshop on crystalline ion beams

    International Nuclear Information System (INIS)

    Hasse, R.W.; Hofmann, I.; Liesen, D.

    1989-04-01

    The workshop consisted of mainly invited and some contributed papers. More informal discussions took place in three working groups on the following topics: beam cooling techniques; diagnostics of crystalline beams; storage rings for crystalline beams. The present volume collects all papers as well as the summaries of the working groups. See hints under the relevant topics. (orig./HSI)

  16. Determination of cellulose I crystallinity by FT-Raman spectroscopy

    Science.gov (United States)

    Umesh P. Agarwal; Richard S. Reiner; Sally A. Ralph

    2009-01-01

    Two new methods based on FT-Raman spectroscopy, one simple, based on band intensity ratio, and the other, using a partial least-squares (PLS) regression model, are proposed to determine cellulose I crystallinity. In the simple method, crystallinity in semicrystalline cellulose I samples was determined based on univariate regression that was first developed using the...

  17. Quantitative aspects of crystalline lactose in milk products

    NARCIS (Netherlands)

    Roetman, K.

    1982-01-01

    The occurrence of crystalline lactose in milk products and its influence on their physical properties are briefly reviewed. The importance of the quantitive determination of crystalline lactose for scientific and industrial purposes is indicated, and a summary is given of our earlier work. This

  18. Multiscale Modeling of Thermal Conductivity of Polymer/Carbon Nanocomposites

    Science.gov (United States)

    Clancy, Thomas C.; Frankland, Sarah-Jane V.; Hinkley, Jeffrey A.; Gates, Thomas S.

    2010-01-01

    Molecular dynamics simulation was used to estimate the interfacial thermal (Kapitza) resistance between nanoparticles and amorphous and crystalline polymer matrices. Bulk thermal conductivities of the nanocomposites were then estimated using an established effective medium approach. To study functionalization, oligomeric ethylene-vinyl alcohol copolymers were chemically bonded to a single wall carbon nanotube. The results, in a poly(ethylene-vinyl acetate) matrix, are similar to those obtained previously for grafted linear hydrocarbon chains. To study the effect of noncovalent functionalization, two types of polyethylene matrices. -- aligned (extended-chain crystalline) vs. amorphous (random coils) were modeled. Both matrices produced the same interfacial thermal resistance values. Finally, functionalization of edges and faces of plate-like graphite nanoparticles was found to be only modestly effective in reducing the interfacial thermal resistance and improving the composite thermal conductivity

  19. Diffractometric method for determining the degree of crystallinity of materials

    Energy Technology Data Exchange (ETDEWEB)

    Chukhchin, D. G., E-mail: dimatsch@mail.ru; Malkov, A. V.; Tyshkunova, I. V.; Mayer, L. V.; Novozhilov, E. V. [Lomonosov Northen (Arctic) Federal University (Russian Federation)

    2016-05-15

    A new method for determining the degree of crystallinity of a material from X-ray diffraction data has been developed. The method is based on estimating the rate of change in function I = f(2θ) in the entire range of scattering angles. A calculation is performed using the ratio of the integral modulus of the first derivative of intensity with respect to angle 2θ to the integral area under the diffraction pattern curve. The method was tested on two substances with known amorphous and crystalline components. A linear relationship is revealed between the specified ratio of crystalline and amorphous parts and the calculated crystallinity index. The proposed method allows one to estimate impartially and compare the degree of crystallinity for samples of different nature.

  20. Electroactive polymers for sensing

    Science.gov (United States)

    2016-01-01

    Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer–metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units. PMID:27499846