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Containing Poly (containing + poly)
Selected AbstractsSolid-State Conversion of Processable 3,4-Ethylenedioxythiophene (EDOT) Containing Poly(arylsilane) Precursors to , -Conjugated Conducting Polymers,ADVANCED MATERIALS, Issue 6 2008Jayesh G. Bokria The thermal degradation products of poly(methyl meth acrylate) model compounds in an ambient atmosphere were mapped via high-resolution electrospray ionization quadrupole ion trap time of flight (Q-ToF) mass spectro metry. [source] Donor/Spacer/Acceptor Block Copolymer Containing Poly(2,7-carbazole) and Perylenetetracarboxydiimide SubunitsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13 2010Changduk Yang Abstract A straightforward synthesis of a conjugated rod/spacer/rod-type block copolymer containing PCz electron-donor and PDI electron-acceptor blocks is described. Two chromophores are covalently connected through sebacate units as saturated spacer. The resulting donor/spacer/acceptor-type block copolymer (PCz-S-PDI) can be applied to limit charge recombination between donor/acceptor interfaces and to control the scale length of nanostructure formation. PCz-S-PDI was used to produce a solar cell with the power conversion efficiency of 0.004%. [source] Novel Polymer Electrolyte Membrane, Based on Pyridine Containing Poly(ether sulfone), for Application in High-Temperature Fuel CellsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 21 2005Elefterios K. Pefkianakis Abstract Summary: Novel poly(aryl ether sulfone) copolymers containing 2,5-biphenylpyridine and tetramethyl biphenyl moieties were synthesized by polycondensation of 4-fluorophenyl sulfone with 2,5-(4,,4, dihydroxy biphenyl)pyridine and tetramethyl biphenyl diol. Copolymers with different molecular weights and different monomer compositions were obtained. These copolymers exhibit excellent film-forming properties, mechanical integrity, and high modulus up to 250,°C, high glass transition temperatures (above 280,°C) as well as high thermal stability up to 400,°C. In addition to the above properties required for PEMFC application, this novel material shows high oxidative stability and acid doping ability, enabling proton conductivity in the range of 10,2 S,·,cm,1 above 130,°C. Synthesis of copolymers with high acid uptake and ionic conductivity. [source] Elongational Rheology of Polymer/Clay Dispersions: Determination of Orientational Extent in Elongational Flow Processes,MACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2008Eduard A. Stefanescu Abstract The purpose of the present contribution is to provide an efficient method that would help to quantify the orientational levels occurring in polymer/clay dispersions subjected to elongational flow. The extent of internal orientation developed in salt containing montmorillonite/poly(ethylene oxide) gels is investigated, combining shear and elongational rheology methods. Entropic changes indicate that the strength of the transient network present in each gel affects the orientational ability of clay particles and polymer chains. We found that an increased Hencky strain of the hyperbolic die leads to a higher variation of the calculated entropy of the material. [source] The Influence of UV Irradiation on Ketonic Defect Emission in Fluorene-Based Copolymers,ADVANCED FUNCTIONAL MATERIALS, Issue 17 2008Horst Scheiber Abstract The influence of UV irradiation in inert atmosphere on the emission spectrum of fluorenone containing poly[9,9-bis(2-ethyl)hexylfluorene] (PF2/6) has been investigated by means of optical absorption, photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy. It is shown that a substantial reduction of green emission arising from ketonic defect sites can be achieved by irradiation of thin films with UV light. This is found to be accompanied by partial cross-linking of the films. FTIR measurements show no reduction of the C=O stretching mode upon irradiation, and, moreover, the degree of cross-linking does not scale with the relative fluorenone content (0.1, 0.5, and 5%). Therefore, the reduced emission intensity in the green spectral region is rather associated with the occurrence of interruptions in the polymer backbone, which reduce the effective conjugation length and subsequently inhibit the energy transfer onto the ketonic defect sites. The found results enabled us to build organic light emitting devices (OLEDs) that can be structured by selective illumination of the emitting layer with an intense UV light source. This method allows for the fabrication of rather efficient (2000,cd,m,2 at 7,V) two-color OLEDs. [source] Release behavior of freeze-dried alginate beads containing poly(N -isopropylacrylamide) copolymersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Jae-Hyung Choi Abstract Beads composed of alginate, poly(N -isopropylacrylamide) (PNIPAM), the copolymers of N -isopropylacrylamide and methacrylic acid (P(NIPAM- co -MAA)), and the copolymers of N -isopropylacrylamide, methacrylic acid, and octadecyl acrylate (P(NIPAM- co -MAA- co -ODA)), were prepared by dropping the polymer solutions into CaCl2 solution. The beads were freeze-dried and the release of blue dextran entrapped in the beads was observed in distilled water with time and pH. The degree of release was in the order of alginate bead < alginate/PNIPAM bead , alginate/P(NIPAM- co -MAA) bead < alginate/P(NIPAM- co -MAA- co -ODA) bead. On the other hand, swelling ratios reached steady state within 20 min, and the values were 200,800 depending on the bead composition. The degree of swelling showed the same order as that of release. Among the beads, only alginate/P(NIPAM- co -MAA- co -ODA) bead exhibited pH-dependent release. At acidic condition, inter- and intraelectrostatic repulsion is weak and P(NIPAM- co -MAA- co -ODA) could readily be assembled into an aggregate due to the prevailing hydrophobic interaction of ODA. Thus, it could block the pore of bead matrix, leading to a suppressed release. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] PLGA nanospheres for the ocular delivery of flurbiprofen: Drug release and interactionsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2008E. Vega Abstract Poly(D,L -lactide- co -glycolide) nanospheres incorporating flurbiprofen were prepared by the solvent displacement technique for purposes of assessing (i) drug,polymer physicochemical interactions, (ii) flurbiprofen release from the polymer matrix and (iii) eye permeation of the drug formulated in the colloidal system. The resulting nanospheres were on average 200,300 nm in size and bore a negative charge (,-potential around ,25 mV). They were shown by atomic force microscopy and transmission electron microscopy to be spherical and regular in shape. Thermal methods, infrared spectroscopy and X-ray diffraction showed that the drug was dispersed inside the particles. These tests evidenced an eutectic mixture meaning more widespread dispersion of the drug in the polymer system. Entrapped flurbiprofen was released in vitro from the polymer system by dissolution and diffusion in high drug loaded nanospheres, whereas those with a lesser load showed only diffusion. The ex vivo corneal permeation study showed that flurbiprofen-loaded nanospheres enhanced drug penetration by about twofold over commercial eye drops containing poly(vinyl alcohol) and by about fourfold over flurbiprofen in pH 7.4 phosphate buffer. The corneal hydration level of each cornea was determined to evaluate potential corneal damage. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:5306,5317, 2008 [source] Synthesis of networked polymers with lithium counter cations from a difunctional epoxide containing poly(ethylene glycol) and an epoxide monomer carrying a lithium sulfonate salt moietyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2010Kozo Matsumoto Abstract Poly(ethylene glycol)-based networked polymers that had lithium sulfonate salt structures on the network were prepared by heating a mixture of poly(ethylene glycol) diglycidyl ether (PEGGE), poly(ethylene glycol) bis(3-aminopropyl) terminated (PEGBA), and an ionic epoxy monomer, lithium 3-glycidyloxypropanesulfonate (LiGPS). Flexible self-standing networked polymer films showed high thermal stability, low crystallinity, low glass transition temperature, and good mechanical strength. The materials were ion conductive at room temperature even under a dry condition, although the ionic conductivity was rather low (10,6 to 10,5 S/m). The ionic conductivity increased with the increase in temperature to above 1 × 10,4 S/m at 90 °C. The film samples became swollen by immersing in propylene carbonate (PC) or PC solution of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The samples swollen in PC showed higher ionic conductivity (ca.1 × 10,3 S/m at room temperature), and the samples swollen in LiTFSI/PC showed much higher ionic conductivity (nearly 1 S/m at room temperature). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3113,3118, 2010 [source] Preparation of monodisperse nanoparticles containing poly(propylene imine)(NH2)32 -polystyreneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2009Hu Liu Abstract Polypropylenimine dendrimer (DAB-Am-32, generation 4.0) was converted into a macroinitiator DAB-Am-32-Cl via reaction with 2-chloropropionyl chloride. Monodisperse nanoparticles containing poly(propylene imine)(NH2)32 -polystyrene were prepared by emulsion atom transfer radical polymerization (ATRP) of styrene (St), using the DAB-Am-32-Cl/CuCl/bpy as initiating system. The structure of macroinitiator was characterized by FTIR spectrum, 1H NMR, and 13C NMR. The structure of poly(propylene imine)(NH2)32 -polystyrene was characterized by FT-IR spectrum and 1H NMR; the molecular weight and molecular weight distribution of poly(propylene imine)(NH2)32 -polystyrene were characterized by gel permeation chromatograph (GPC). The morphology, size and size distribution of the nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The effects of monomer/macroinitiator ratio and surfactant concentration on the size and size distribution of the nanoparticles were investigated. It was found that the diameters of the nanoparticles were smaller than 100 nm (30,80 nm) and monodisperse; moreover, the particle size could be controlled by monomer/macroinitiator ratios and surfactant concentration. With the increasing of the ratio of St/DAB-Am-32-Cl, the number-average diameter (Dn), weight-average diameter (Dw) were both increased gradually. With enhancing the surfactant concentration, the measured Dh of the nanoparticles decreased, while the polydispersity increased. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2892,2904, 2009 [source] Synthesis and characterization of phthalazinone containing poly(arylene ether)s via a novel N,C coupling reactionJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2003S. J. Wang Abstract High-molecular-weight poly(phthalazinone)s with very high glass-transition temperatures (Tg's) were synthesized via a novel N,C coupling reaction. New bisphthalazinone monomers (7a,e) were synthesized from 2-(4-chlorobenzoyl) phthalic acid in two steps. Poly(phthalazinone)s, having inherent viscosities in the range of 0.34,0.91 dL/g, were prepared by the reaction of the bis(phthalazinone) monomers with an activated aryl halide in a dipolar aprotic solvent in the presence of potassium carbonate. The poly(phthalazinone)s exhibited Tg's greater than 230 °C. polymer 8b synthesized from diphenyl biphenol and bis(4-flurophenyl) sulfone demonstrated the highest Tg of 297 °C. Thermal stabilities of the poly(phthalazinone)s were determined by thermogravimetric analysis. All the poly(phthalazinone)s showed a similar pattern of decomposition with no weight loss below 450 °C in nitrogen. The temperatures of 5% weight loss were observed to be about 500 °C. The poly(phthalazinone)s containing 4,4,-isopropylidenediphenol and 4,4,-(hexafluoroisopropylidene) diphenol and diphenyl ether linkage were soluble in chlorinated solvents such as chloroform. Other poly-(phthalazinone)s were soluble in dipolar aprotic solvents such as N,N,-dimethylacetamide. The soluble poly(phthalazinone)s can be cast as flexible films from solution. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2481,2490, 2003 [source] Crystallization and Ring-Banded Spherulite Morphology of Poly(ethylene oxide)- block -Poly(, -caprolactone) Diblock CopolymerMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2004Shichun Jiang Abstract Summary: The crystallization behavior of crystalline-crystalline diblock copolymer containing poly(ethylene oxide) (PEO) and poly(, -caprolactone) (PCL), in which the weight fraction of PCL is 0.815, has been studied via differential scanning calorimeter (DSC), wide-angle X-ray diffraction (WAXD), and polarized optical microscopy (POM). DSC and WAXD indicated that both PEO and PCL blocks crystallize in the block copolymer. POM revealed a ring-banded spherulite morphology for the PEO- b -PCL diblock copolymer. DSC heating curve for the PEO- b -PCL block copolymer. [source] Properties of recycled material containing poly(vinyl chloride), polypropylene, and calcium carbonate nanofillerPOLYMER ENGINEERING & SCIENCE, Issue 3 2008Branka Andri Even at low content, polypropylene significantly worsens mechanical properties of the recycled PVC composite, i.e. tensile strength at break and elongation at break. But, if small quantities of surface modified nanofiller calcium carbonate is added, an applicable composite that contains 10,30% of waste material can be made. It was determined that nanosized calcium carbonate lowers melting point of polypropylene, perhaps by changing its crystalline form and has no influence on thermooxidative degradation of poly(vinyl chloride). Addition of nanofiller slightly lowers the surface free energy of the composites what is more prone when the low content of polypropylene is present. The recovery of tensile strength and elongation at break occurs and those properties reach the highest value at about 6% of CaCO3. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] A lithium ionomer of poly(ethylene-co-methacrylic acid) copolymer as compatibilizer for blends of poly(ethylene terephthalate) and high density polyethylenePOLYMER ENGINEERING & SCIENCE, Issue 11 2002A. Retolaza Blends of 75/25 poly(ethylene terephthalate) (PET)/high density polyethylene (HDPE) containing poly(ethylene-co-methacrylic acid) partially neutralized with lithium (PEMA-Li) were obtained by direct injection molding in an attempt (i) to ameliorate the poor performance of the binary blend and (ii) to find the best compatibilizer content. The presence of PEMA-Li caused a nucleation effect on PET, and a decrease in the crystalline content of HDPE. The compatibilizing effect of PEMA-Li was due to the combined effects of interaction at the interface and chemical reactions. The ternary blends showed a complex morphology, with two dispersed HDPE and PEMA-Li phases that contained a small internal dispersed phase, probably of PET. The compatibilizing effect of PEMA-Li was clearly shown by means of an impressive increase in the ductility and to a minor extent in the impact strength. The highest property improvement (ductility increase 1450%) appeared upon the addition of 45% PEMA-Li with respect to the HDPE phase, but taking into account the recycling interest, the ternary blend with the addition of roughly 22.5% PEMA-Li appears to be the most attractive. [source] Effects of poly(ethylene- co -propylene) elastomer on mechanical properties and combustion behaviour of flame retarded polyethylene/magnesium hydroxide compositesPOLYMER INTERNATIONAL, Issue 7 2002Zhengzhou Wang Abstract Magnesium hydroxide-based halogen-free flame retarded linear low density polyethylene composites containing poly(ethylene- co -propylene) elastomer were prepared in the melt process and subsequently vulcanized thermally. Influences of the elastomer on the mechanical properties, combustion characteristics and crystallization behaviour of polyethylene/magnesium hydroxide composites have been investigated. The results from the mechanical tests show that the incorporation of a suitable amount of elastomer into polyethylene/magnesium hydroxide composites after vulcanization can increase both the tensile strength and elongation greatly, compared with those of the composites without the elastomer. It has been found that the properties such as limiting oxygen index, UL-94 rating, the time to ignition and the rate of heat release of polyethylene/magnesium hydroxide/elastomer composites are all improved in comparison with polyethylene/magnesium hydroxide composites at the same retardant level. Scanning electron microscopy studies show that the incorporation of the elastomer into polyethylene/magnesium hydroxide composites improves the compatibility between the filler and the polymer substrate. The degrees of crystallinity of polyethylene/magnesium hydroxide/elastomer composites decrease with increasing the elastomer content. © 2002 Society of Chemical Industry [source] Networks for recognition of biomolecules: molecular imprinting and micropatterning poly(ethylene glycol)- Containing films,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10-12 2002Mark E. Byrne Abstract Engineering the molecular design of biomaterials by controlling recognition and specificity is the first step in coordinating and duplicating complex biological and physiological processes. Studies of protein binding domains reveal molecular architectures with specific chemical moieties that provide a framework for selective recognition of target biomolecules in aqueous environment. By matching functionality and positioning of chemical residues, we have been successful in designing biomimetic polymer networks that specifically bind biomolecules in aqueous environments. Our work addresses the preparation, behavior, and dynamics of the three-dimensional structure of biomimetic polymers for selective recognition via non-covalent complexation. In particular, the synthesis and characterization of recognitive gels for the macromolecular recognition of D -glucose is highlighted. Novel copolymer networks containing poly(ethylene glycol) (PEG) and functional monomers such as acrylic acid, 2-hydroxyethyl methacrylate, and acrylamide were synthesized in dimethyl sulfoxide (polar, aprotic solvent) and water (polar, protic solvent) via UV-free radical polymerization. Polymers were characterized by single and competitive equilibrium and kinetic binding studies, single and competitive fluorescent and confocal microscopy studies, dynamic network swelling studies, and ATR-FTIR. Results qualitatively and quantitatively demonstrate effective glucose-binding polymers in aqueous solvent. Owing to the presence of template, the imprinting process resulted in a more macroporous structure as exhibited by dynamic swelling experiments and confocal microscopy. Polymerization kinetic studies suggest that the template molecule has more than a dilution effect on the polymerization, and the effect of the template is related strongly to the rate of propagation. In addition, PEG containing networks were micropatterned to fabricate microstructures, which would be the basis for micro-diagnostic and tissue engineering devices. Utilizing photolithography techniques, polymer micropatterns of a variety of shapes and dimensions have been created on polymer and silicon substrates using UV free-radical polymerizations with strict spatial control. Micropatterns were characterized using optical microscopy, SEM, and profilometry. The processes and analytical techniques presented are applicable to other stimuli-sensitive and recognitive networks for biomolecules, in which hydrogen bonding, hydrophobic, or ionic contributions will direct recognition. Further developments are expected to have direct impact on applications such as analyte controlled and modulated drug and protein delivery, drug and biological elimination, drug targeting, tissue engineering, and micro- or nano-devices. This work is supported by NSF Grant DGE-99-72770. 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