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Immiscible Polymers (immiscible + polymer)

Distribution by Scientific Domains
Polymers and Materials Science100%

Terms modified by Immiscible Polymers

  • immiscible polymer blend
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    Selected Abstracts

    Immiscible polymers in double spin-coated electroluminescent devices containing phenyl-substituted tris(8-hydroxyquinoline)aluminum derivatives soluble in a host polymer

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2003
    E. Shoji
    Abstract Three new phenyl-substituted tris(8-hydroxyquinoline)aluminum (AlQ3) derivatives have been synthesized: tris(5-phenyl-8-quinolinolate-N1,O8)aluminum, tris(5,7-diphenyl-8-quinolinolate-N1,O8)aluminum, and tris[5,7-bis(p -fluorophenyl)-8-quinolinolate-N1,O8]aluminum. These AlQ3 derivatives are easily soluble in common organic solvents and form solid-phase solutions in a poly(aryl ether ketone) host polymer (A435). These interesting properties allow the use of soluble AlQ3 derivatives in double spin-coated organic light-emitting devices of the type ITO/NPB-QP/A435 + 50 wt % soluble AlQ3 derivative/Mg, where NPB-QP is a hole-transporting polymer insoluble in toluene, the solvent for A435. Typical double spin-coated organic layer devices are characterized by an emission at 530,539 nm, a threshold voltage of 6,9 V, and a maximum luminance of 1800,4000 cd/m2 at 21,25 V. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3006,3016, 2003 [source]

    Generation of Compositional-Gradient Structures in Biodegradable, Immiscible, Polymer Blends by Intermolecular Hydrogen-Bonding Interactions,

    ADVANCED FUNCTIONAL MATERIALS, Issue 10 2005
    B. Hexig
    Abstract A biodegradable, immiscible poly(butylenes adipate- co -butylenes terephthalate) [P(BA- co -BT)]/poly(ethylene oxide) (PEO) polymer blend film with compositional gradient in the film-thickness direction has been successfully prepared in the presence of a low-molecular-weight compound 4,4,-thiodiphenal (TDP), which is used as a miscibility-enhancing agent. The miscibilities of the P(BA- co -BT)/PEO/TDP ternary blend films and the P(BA- co -BT)/PEO/TDP gradient film were investigated by differential scanning calorimetry (DSC). The compositional gradient structure of the P(BA- co -BT)/PEO/TDP (46/46/8 w/w/w) film has been confirmed by microscopic mapping measurement of Fourier-transform infrared spectra and dynamic mechanical thermal analysis. We have developed a new strategy for generating gradient-phase structures in immiscible polymer-blend systems by homogenization, i.e., adding a third agent that can enhance the miscibility of the two immiscible polymers through simultaneous formation of hydrogen bonds with two component polymers. [source]

    Ultra-Small-Angle X-Ray Scattering Study of PET/PC Nanolayers and Comparison to AFM Results

    MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13 2008
    Fernando Ania
    Abstract The forced assembly of two immiscible polymers, produced by layer-multiplying co-extrusion, is analyzed by means of USAXS. Comparison of scattering and AFM results sheds light on many details of the nanolayered structure in PET/PC films. The role played by the volume concentration and cold crystallization of PET on the experimental scattering is discussed. The appearance of at least two scattering maxima in all cases, corresponding to higher orders of the same repeating distance, accounts for the high regularity of the developed nanostructure. It is finally shown that long spacing values, derived from a localized area in AFM, are in a good agreement with the USAXS values averaged over much larger areas. [source]

    Monte Carlo Simulation of Polymer Reactions at Interfaces

    MACROMOLECULAR THEORY AND SIMULATIONS, Issue 4 2007
    Andreas John
    Abstract Adhesion of immiscible polymers during two-component injection moulding may be improved by transreactions of properly functionalised components. We performed MC simulations based on the three-dimensional coarse-grained bond fluctuation model (BFM) including a thermal interaction potential in with energy to characterise the behaviour of several selected types of chemical reactions, which are governed by activation energies of EA,=,0, 1, 3 and 5 kBT. The consumption of reactive monomers for all the reactions in the time interval below the Rouse time ,R exhibits a typical crossover from a kinetic-controlled to a diffusion-controlled behaviour and can be described by a bimolecular kinetic ansatz. [source]

    Extrusion of polyethylene/polypropylene blends with microfibrillar-phase morphology

    POLYMER COMPOSITES, Issue 8 2010
    Martina Polaskova
    Extrusion of immiscible polymers under special conditions can lead to creation of microfibrillar-phase morphology, ensuring significant increase of mechanical properties of polymer profiles. Polyethylene/polypropylene blend extrudates with microfibrillar-phase morphology (polypropylene microfibrils reinforcing polyethylene matrix phase) were prepared through continuous extrusion with semihyperbolic-converging die enabling elongation and orientation of microfibrils in flow direction. Structure of extruded profiles was examined using electron microscopy and wide-angle X-ray scattering. Tensile tests proved that extrudates with microfibrillar-phase morphology show significantly higher mechanical properties than the conventional extrudates. The presented concept offers possibility of replacing the existing expensive multi-component medical devices with fully polymeric tools. POLYM. COMPOS., 31:1427,1433, 2010. © 2009 Society of Plastics Engineers [source]

    Morphology development during blending of immiscible polymers in screw extruders

    POLYMER ENGINEERING & SCIENCE, Issue 6 2002
    Sandeep Tyagi
    The present work reports evolution of morphology from initial (presence of striation) to final (droplet formation) stages in a single-screw extruder. Morphology development during the blending process controls the final size of the dispersed phase, which in turn significantly affects the properties of the blends. The experiments were carried out using a 70/30 wt% polypropylene/ethylene vinyl acetate (PP/EVA) blend; samples were collected along the length of the screw, by screw pullout experiment, to analyze the size and size distribution of the dispersed phase present both as striated layers and subsequently as droplets. Average size of the dispersed phase and standard deviation were taken into account to monitor the morphology evolution along the length of the screw. Pre-breakup morphology development was studied by analyzing the sample collected from the feed zone of the extruder in terms of upper and lower layers along the cross section of screw channel. Examination of micrographs revealed the existence of pattern of ordered striations along the length of the melting zone containing striations from average size of 1000 ,m down to 50 ,m decreasing rapidly along the length of the screw. The breakup process was captured at the start of compression zone where step-up in the shear as well as elongational flow was applied due to decrease in the channel depth along the compression zone. The observed droplet size formed by the breakup of filaments is found to be in accordance with theory. The final droplet size is found to be governed by the emulsification process occurring as a result of stretching, breakup and coalescence in the metering section of the screw and is in the order of 2 ,m. [source]

    Morphology and thermal properties of a PC/PE blend with reactive compatibilization

    POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2007
    Bo Yin
    Abstract Reactive compatibilization of immiscible polymers is becoming increasingly important and hence a representative study of a polycarbonate/high density polyethylene (PC/HDPE) system is the focus of this paper. A grafted copolymer PC- graft -ethylene- co -acrylic acid (PC- graft -EAA) was generated as a compatibilizer in situ during processing operation by ester and acid reaction between PC and ethylene-acrylic acid (EAA) in the presence of the catalyst dibutyl tin oxide (DBTO). As the polyethylene (PE) matrix does not play any part during the synthesis of the copolymer and since PC and EAA are also immiscible, to simplify the system, the influence of this copolymer formation at the interface between PC and EAA on rheological properties, phase morphology, and crystallization behavior for EAA/PC binary blends was first studied. The equilibrium torque increased with the DBTO content increasing in EAA/PC blends on Haake torque rheometer, indicating the in situ formation of the graft copolymer. Scanning electron microscopy (SEM) studies of cryogenically fractured surfaces showed a significant change at the distribution and dispersion of the dispersed phase in the presence of DBTO, compared with the EAA/PC blend without the catalyst. Differential scanning calorimetry (DSC) studies suggested that the heat of fusion of the EAA phase in PC/EAA blends with or without DBTO reduced with the formation of the copolymer compared with pure EAA. Then morphological studies and crystallization behavior of the uncompatibilized and compatibilized blends of PC/PE were studied as functions of EAA phase concentration and DBTO content. Morphological observations in PC/PE blends also revealed that on increasing the EAA content or adding the catalyst DBTO, the number of microvoids was reduced and the interface was intensive as compared to the uncompatibilized PC/PE blends. Crystallization studies indicated that PE crystallized at its bulk crystallization temperature. The degree of crystallinity of PE phase in PC/PE/EAA blends was also reduced with the addition of EAA and DBTO compared to the uncompatibilized blends of PC/PE, indicating the decrease in the degree of crystallinity was more in the presence of PC- graft -EAA. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Electrically conductive sensors for liquids based on ternary immiscible polymer blends containing polyaniline

    POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10 2004
    H. Cooper
    Abstract Electrically conductive blends, containing two immiscible polymers (ethylene vinyl acetate, EVA-19, and copolyamide 6/6.9, CoPA) and polyaniline (PANI), were produced by melt processing. These blends showed a preferred localization of PANI in the CoPA phase, thus enhancing the formation of continuous conducting networks. Electrically conductive PANI-containing filaments produced by a capillary rheometer process at various shear rate levels were studied as sensing materials for a homologous series of alcohols (methanol, ethanol and 1-propanol). All filaments showed a decreasing resistance upon exposure to these solvents. Filaments exposed to methanol, liquid or vapor, exhibited the highest resistance decrease. This behavior was related to the highest polarity of methanol, compared with ethanol and 1-propanol. The filaments' rate of production significantly affects the relative resistance change upon exposure to the various alcohols and their reproducibility. Copyright © 2004 John Wiley & Sons, Ltd. [source]